Original quantitative research – Assessing the impact of the COVID-19 pandemic on the mental health–related hospitalization rate of youth in Canada: an interrupted time series analysis

Abstract

Introduction: This study evaluated the effect of the COVID-19 pandemic on temporal trends in mental health and addiction–related inpatient hospitalization rates among youth (aged 10–17 years) in Canadian provinces and territories (excluding Quebec) from 1 April 2018 to 5 March 2022.

Methods: We conducted an interrupted time series analysis across three periods: T0 (pre-pandemic: 1 April 2018 to 15 March 2020); T1 (early pandemic: 15 March 2020 to 5 July 2020); and T2 (later pandemic: 6 July 2020 to 5 March 2022).

Results: Pre-pandemic mental health and addiction–related hospitalization rates had significant regional variability, with weekly rates from 6.27 to 85.59 events per 100 000 persons in Manitoba and the territories combined, respectively. During T1, the national (excluding Quebec) weekly hospitalization rate decreased from a pre-pandemic level of 12.82 (95% CI: 12.14 to 13.50) to 5.11 (95% CI: 3.80 to 6.41) events per 100 000 persons. There was no statistically significant change in the mental health and addiction–related hospitalization rate across provinces and territories in T2 compared to T0. However, there was a significant increase in the rate of self-harm–related hospitalizations among females Canada-wide and in most provinces during this period.

Conclusion: Although several Canadian studies have reported increases in mental health and addiction–related outpatient and emergency department visits among youth during the COVID-19 pandemic, this did not correspond to an increase in the inpatient hospital burden, with the notable exception of self-harm among young females.

Keywords: mental health, self-harm, substance use–related disorders, youth, adolescents, time series, COVID-19, Canada

Introduction

Social isolation as a result of lockdowns and other societal changes during the COVID-19 pandemic led to a significant increase in mental health disorders such as anxiety, depression and post-traumatic stress disorder, resulting in higher outpatient and emergency department mental health–related visits for youths (<18 years).^{Footnote 1Footnote 2Footnote 3Footnote 4Footnote 5Footnote 6} Loneliness, anxiety and depression have been on the rise in this population, especially among young females.^{Footnote 7Footnote 8Footnote 9} In 2020, females aged 15 to 17 years were twice as likely to be hospitalized for mental health–related disorders than their male counterparts.^{Footnote 10}

Studies focusing on changes in mental health–related emergency department visits and health service utilization among Canadian youths have been conducted in British Columbia, Ontario and Montréal (Quebec).^{Footnote 2Footnote 6Footnote 11Footnote 12Footnote 13Footnote 14Footnote 15} However, there is a lack of research on national and provincial/territorial trends in mental health–related inpatient hospitalizations. With different provincial and territorial public health responses to the pandemic, there may be differences in magnitudes, trends and associations in regional mental health–related hospitalization rates.

Our aim was to assess inpatient hospitalization rates for mental health and addiction diagnoses among Canadian youth across three distinct periods: pre-pandemic (T0), early pandemic (T1) and later pandemic (T2). Focusing on Canadian provinces and territories, excluding Quebec, we provide a detailed analysis, stratified by sex, for youth aged 10 to 17 years. It is important to note that our analysis is specific to inpatient hospitalizations and does not encompass the entire spectrum of youth mental health–related events, such as outpatient and emergency department visits.

Methods

We conducted a retrospective cohort study using routinely collected administrative health data of hospital admissions between 1 April 2018 and 5 March 2022. This allowed us to capture mental health–related inpatient hospitalizations for approximately 2 years before and 2 years after the start of the COVID-19 pandemic (set as 15 March 2020). Our analysis included individuals aged 10 to 17 years with a valid Medicare health card number at the time of hospitalization.

Data were obtained from the Canadian Institute for Health Information's Discharge Abstract Database (DAD) housed at the Public Health Agency of Canada. The Discharge Abstract Database is a comprehensive national (excluding Quebec) database that has been capturing hospital discharge abstracts for acute, chronic and rehabilitative care since 1988.^{Footnote 16} The use of these administrative data is authorized under section 44 of Ontario's Personal Health Information Protection Act, which does not require review by a research ethics board.^{Footnote 17}

Outcomes

The primary outcome was an inpatient hospitalization for a diagnosis related to mental health and addiction, including any diagnosis of deliberate self-harm or substance use-related disorder. The secondary outcomes were: (1) inpatient hospitalization with a diagnosis of deliberate self-harm; and (2) inpatient hospitalization with a diagnosis of substance use disorder (including poisoning codes).^{Footnote 18} The code algorithms used were based on Canadian Institute for Health Information (CIHI) definitions.^{Footnote 18Footnote 19Footnote 20} Unless otherwise stated, the primary and secondary outcomes were summarized as number of weekly events per 100 000 persons. An event constitutes one episode of care, which refers to all continuous inpatient hospitalizations (including transfers within or between facilities) as defined by the Canadian Institute for Health Information (CIHI). Transfers were considered one episode of care if they occurred less than 7 hours after discharge, regardless of whether there was a transfer code, or less than 12 hours after discharge if at least one of the visits had a transfer code.^{Footnote 21} Two or more separate events from the same individual are counted as multiple events rather than a single event. We estimated annual population counts of youth aged 10 to 17 years using Statistics Canada's annual population estimates, broken down by sex and region.^{Footnote 22} The same estimated population was used for the entire calendar year; this assumed a constant annual population growth, which appeared to be supported by the data. Age was calculated on the date of admission and province was determined based on the issuing health card.

Statistical analysis

We conducted an interrupted time-series analysis to assess the impact of the pandemic on trends and rates of mental health-related hospitalizations before and after 15 March 2020. We used segmented linear regression analysis on the weekly hospitalization rates in all of Canada (except Quebec), as well as each region (i.e. province/territory) spanning 104 weeks (2 years) before the pandemic.

We expected trends during the early weeks of the pandemic to differ from those during the overall pandemic as individuals and institutions adjusted to changes in service delivery and diagnosis of mental health-related events. Hence, we examined two interruptions: (1) early pandemic period spanning 16 weeks, and (2) the rest of the pandemic period spanning 89 weeks. We refer to the pre-pandemic period as T0 (1 April 2018 to 14 March 2020), the early pandemic period as T1 (15 March 2020 to 5 July 2020) and the later pandemic period as T2 (6 July 2020 to 5 March 2022). We chose 5 July 2020 as the end of T1 as some American studies had shown that hospitalization rates returned to expected rates between late June and mid July.^{Footnote 23} Furthermore, this was also the first period where most provinces and territories relaxed some public health measures.^{Footnote 24}

We combined data from the territories (Yukon, Northwest Territories and Nunavut) and the Atlantic provinces (New Brunswick, Prince Edward Island, Nova Scotia, and Newfoundland and Labrador) due to a small number of events for some analyses. To ensure that patterns within different youth age groups were assessed, we also stratified the Canada-wide results by age: 10 to 14 years and 15 to 17 years.

The model included coefficients for T0 (102 weeks), T1 (16 weeks) and T2 (89 weeks). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).^{Footnote 25} We confirmed that model assumptions of homoscedasticity, linearity and normality (assessed graphically) were met for all models. We tested for autocorrelation using the Durbin–Watson statistic and used the Cook D statistic to ensure there were no influential data points.^{Footnote 25} All analyses were conducted using SAS version 9.4 (SAS Institute Inc., Cary, NC, US) with a modified version of an interrupted time-series SAS macro.^{Footnote 26}

For each study group, we presented the baseline hospitalization rate per 100 000 as well as the trend (stable, statistically significantly increasing, statistically significantly decreasing) during three periods (T0, T1 and T2).

Results

There were 73 907 mental health and addiction–related hospitalizations of youth across Canada (except Quebec) during our study period (209 weeks). The mean age was 14.8 years and the median was 15 years (IQR = 2). Females had higher overall mental health and addiction–related hospitalization rates than males across all provinces in an approximately 2:1 ratio (Table 1).

Changes in mental health and addiction–related inpatient hospitalization

The pre-pandemic (T0) provincial/territorial baseline rates for mental health and addiction–related hospitalizations ranged from 6.27 (in Manitoba) to 85.59 (in the territories) weekly events per 100 000 persons. These rates were stable for all provinces and territories during this period (Figures 1a and 1b). In general, hospitalization rates for females were higher than for males. Adjusted for seasonality, the national hospitalization rate during T0 was 12.82 (95% CI: 12.14 to 13.50) weekly events per 100 000 persons (Table 2).

During T1, the average weekly hospitalization rate dropped from 12.82 (95% CI: 12.14 to 13.50) by 7.71 (95% CI: 6.41 to 9.02) events per 100 000 persons, compared to the baseline period. The level change in hospitalization rate dropped to 5.11 (95% CI: 3.80 to 6.41), equating to a 60% (95% CI: 50% to 70%) percentage decrease compared to T0. We also observed a statistically significant increasing trend in the weekly rates per 100 000 persons as the early pandemic progressed. This rate increase was also statistically significant among males in British Columbia, Ontario and Manitoba and females in British Columbia, Ontario, Alberta, Saskatchewan and Manitoba, from highest to lowest rate of increase per sex (Figures 1a and 1b; graphical data not shown for Saskatchewan and Manitoba).

During T2, the national weekly hospitalization rate was similar to T0 for the entire cohort and for males. The female national hospitalization rate increased from 18.20 (95% CI: 17.17 to 19.22) events per 100 000 persons in T0 to 20.29 (95% CI: 18.41 to 22.17) events per 100 000 persons, equating to an 11% (95% CI: 1% to 21.8%) increase (Figures 1a and 1b). There was no statistically significant change in the trend for hospitalization rate during T2 for either males or females at the national or provincial/territorial levels. There were also no notable differences in the national trend for youth aged 10 to 14 years and 15 to 17 years compared to the trend for youth overall.

Figure 1a : Descriptive text

Weekly hospitalization rate (per 100 000) with mental health and addiction diagnosis of female youth (10–17 years) in Canada (except Quebec) and British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	18.16586387	5	22.81946452	2.524633882	13.21758146	23.11414628
2018-05-01	18.45095247	4	18.30344462	2.524633882	13.50267007	23.39923488
2018-06-01	15.60656396	4	15.84596383	2.524633882	10.65828155	20.55484637
2018-07-01	12.02328685	5	14.85658844	2.524633882	7.075004443	16.97156926
2018-08-01	12.04313265	4	11.87250462	2.524633882	7.094850247	16.99141506
2018-09-01	15.12381239	5	18.52685197	2.524633882	10.17552998	20.07209479
2018-10-01	18.20220578	4	18.57472497	2.524633882	13.25392338	23.15048819
2018-11-01	18.27469476	4	19.149201	2.524633882	13.32641235	23.22297716
2018-12-01	10.86119197	6	18.22365438	2.524633882	5.912909565	15.80947438
2019-01-01	16.82444121	4	17.89077509	2.524633882	11.8761588	21.77272362
2019-02-01	17.07864802	4	16.4129782	2.524633882	12.13036561	22.02693043
2019-03-01	17.50770397	5	20.21751912	2.524633882	12.55942156	22.45598638
2019-04-01	17.62687491	4	16.27148701	2.524633882	12.6785925	22.57515732
2019-05-01	17.9170008	4	17.48202276	2.524633882	12.96871839	22.8652832
2019-06-01	15.067575	5	17.46630151	2.524633882	10.1192926	20.01585741
2019-07-01	11.48429789	4	11.08347666	2.524633882	6.536015485	16.4325803
2019-08-01	11.50918098	4	11.19352536	2.524633882	6.560898568	16.45746338
2019-09-01	14.58986071	5	18.39385488	2.524633882	9.6415783	19.53814312
2019-10-01	17.66825411	4	17.04182794	2.524633882	12.7199717	22.61653651
2019-11-01	17.74074308	4	18.09515125	2.524633882	12.79246067	22.68902549
2019-12-01	10.32724029	6	16.43590903	2.524633882	5.378957887	15.2755227
2020-01-01	16.29048953	4	17.30974328	2.524633882	11.34220712	21.23877194
2020-02-01	16.54469634	4	16.45666453	2.524633882	11.59641393	21.49297875
2020-03-01	11.06260403	5	14.53335972	2.524633882	6.11432162	16.01088644
2020-04-01	9.085139623	4	9.352845157	2.524633882	4.136857215	14.03342203
2020-05-01	11.74125273	5	13.75783359	2.524633882	6.792970318	16.68953513
2020-06-01	11.26285143	4	11.92759192	2.524633882	6.314569025	16.21113384
2020-07-01	13.08741443	4	12.96679693	2.524633882	8.13913202	18.03569684
2020-08-01	13.19523605	5	16.31706983	2.524633882	8.246953641	18.14351846
2020-09-01	16.3638916	4	15.78971206	2.524633882	11.41560919	21.31217401
2020-10-01	19.525523	4	18.65915875	2.524633882	14.57724059	24.47380541
2020-11-01	19.68095051	5	22.36617366	2.524633882	14.7326681	24.62923292
2020-12-01	12.36519864	5	14.15623431	2.524633882	7.416916228	17.31348104
2021-01-01	18.42619878	5	23.9705024	2.524633882	13.47791637	23.37448119
2021-02-01	18.76334413	4	19.9445686	2.524633882	13.81506172	23.71162654
2021-03-01	19.27563809	4	20.23764424	2.524633882	14.32735568	24.22392049
2021-04-01	19.47804703	4	20.45359471	2.524633882	14.52976462	24.42632944
2021-05-01	19.85111145	5	26.31510752	2.524633882	14.90282905	24.79939386
2021-06-01	17.08966148	4	17.55368837	2.524633882	12.14137907	22.03794389
2021-07-01	13.58962237	4	14.28358122	2.524633882	8.641339966	18.53790478
2021-08-01	13.697444	5	17.78506388	2.524633882	8.749161587	18.6457264
2021-09-01	16.86609954	4	17.66166361	2.524633882	11.91781714	21.81438195
2021-10-01	20.03246876	5	26.16085719	2.524633882	15.08418635	24.98075117
2021-11-01	20.18789627	4	21.19399633	2.524633882	15.23961386	25.13617868
2021-12-01	12.86740658	5	14.50760721	2.524633882	7.919124175	17.81568899
2022-01-01	18.92840673	5	20.63716686	2.524633882	13.98012432	23.87668913
2022-02-01	19.26555207	4	18.83802923	2.524633882	14.31726967	24.21383448

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	25.29076	5	31.02994	5.041185	15.41003	35.17148
2018-05-01	25.8111	4	23.59301	5.041185	15.93038	35.69182
2018-06-01	22.3904	4	20.51566	5.041185	12.50968	32.27112
2018-07-01	15.08061	5	19.74632	5.041185	5.199886	24.96133
2018-08-01	14.65718	4	16.92542	5.041185	4.776463	24.53791
2018-09-01	18.82116	5	27.31147	5.041185	8.940438	28.70188
2018-10-01	22.80945	4	24.23412	5.041185	12.92872	32.69017
2018-11-01	25.05552	4	25.13168	5.041185	15.1748	34.93624
2018-12-01	14.02405	6	24.46558	5.041185	4.143329	23.90477
2019-01-01	23.30931	4	23.64739	5.041185	13.42859	33.19003
2019-02-01	22.48023	4	20.46898	5.041185	12.59951	32.36095
2019-03-01	23.31373	5	26.95294	5.041185	13.43301	33.19445
2019-04-01	26.76018	4	23.01171	5.041185	16.87945	36.6409
2019-05-01	27.26679	4	24.28308	5.041185	17.38607	37.14751
2019-06-01	23.85982	5	28.98713	5.041185	13.9791	33.74054
2019-07-01	16.55003	4	15.51066	5.041185	6.669306	26.43075
2019-08-01	16.11287	4	17.67198	5.041185	6.23215	25.99359
2019-09-01	20.27685	5	24.91876	5.041185	10.39612	30.15757
2019-10-01	24.26513	4	23.64739	5.041185	14.38441	34.14585
2019-11-01	26.51121	4	28.35145	5.041185	16.63049	36.39193
2019-12-01	15.47974	6	26.29142	5.041185	5.599016	25.36046
2020-01-01	24.765	4	26.35548	5.041185	14.88427	34.64572
2020-02-01	23.93592	4	21.81578	5.041185	14.0552	33.81664
2020-03-01	15.32719	5	19.67203	5.041185	5.446471	25.20792
2020-04-01	14.87638	4	15.38454	5.041185	4.995659	24.7571
2020-05-01	18.4793	5	21.81578	5.041185	8.598573	28.36002
2020-06-01	18.1549	4	18.78931	5.041185	8.274177	28.03562
2020-07-01	19.49873	4	17.65439	5.041185	9.618006	29.37945
2020-08-01	19.18387	5	23.20291	5.041185	9.303151	29.0646
2020-09-01	23.45642	4	21.43747	5.041185	13.57569	33.33714
2020-10-01	27.52748	4	25.22055	5.041185	17.64675	37.4082
2020-11-01	29.89585	5	32.66062	5.041185	20.01513	39.77657
2020-12-01	18.98501	5	22.57314	5.041185	9.104292	28.86574
2021-01-01	28.3909	5	36.33189	5.041185	18.51018	38.27163
2021-02-01	27.68413	4	34.06115	5.041185	17.80341	37.56485
2021-03-01	28.6004	4	30.27658	5.041185	18.71968	38.48112
2021-04-01	32.12962	4	35.95343	5.041185	22.2489	42.01034
2021-05-01	32.75853	5	47.4333	5.041185	22.87781	42.63925
2021-06-01	29.46013	4	31.5381	5.041185	19.57941	39.34085
2021-07-01	22.23311	4	24.22126	5.041185	12.35239	32.11383
2021-08-01	21.91826	5	24.34741	5.041185	12.03754	31.79898
2021-09-01	26.1908	4	24.85202	5.041185	16.31008	36.07152
2021-10-01	30.28766	5	39.35955	5.041185	20.40693	40.16838
2021-11-01	32.65603	4	35.44883	5.041185	22.77531	42.53675
2021-12-01	21.7194	5	21.80606	5.041185	11.83868	31.60012
2022-01-01	31.12529	5	36.13478	5.041185	21.24457	41.00601
2022-02-01	30.41851	4	28.17288	5.041185	20.53779	40.29923

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	17.99589	5	23.14722	3.724103	10.69665	25.29514
2018-05-01	17.50012	4	18.14242	3.724103	10.20087	24.79936
2018-06-01	13.86401	4	14.13857	3.724103	6.564773	21.16326
2018-07-01	11.40997	5	14.01345	3.724103	4.110732	18.70921
2018-08-01	11.74014	4	12.51201	3.724103	4.440901	19.03938
2018-09-01	16.20873	5	19.01826	3.724103	8.909489	23.50797
2018-10-01	19.25458	4	18.51778	3.724103	11.95534	26.55382
2018-11-01	18.52659	4	21.64578	3.724103	11.22735	25.82583
2018-12-01	10.2351	6	16.72683	3.724103	2.935855	17.53434
2019-01-01	18.30444	4	19.49574	3.724103	11.0052	25.60369
2019-02-01	18.03646	4	16.44953	3.724103	10.73722	25.3357
2019-03-01	18.58555	5	21.68901	3.724103	11.28631	25.88479
2019-04-01	17.63572	4	16.32768	3.724103	10.33648	24.93496
2019-05-01	17.14331	4	13.03778	3.724103	9.844065	24.44255
2019-06-01	13.50384	5	16.69323	3.724103	6.204598	20.80308
2019-07-01	11.0498	4	9.626023	3.724103	3.750556	18.34904
2019-08-01	11.38333	4	10.35711	3.724103	4.084092	18.68257
2019-09-01	15.85192	5	21.56717	3.724103	8.55268	23.15116
2019-10-01	18.89777	4	17.42432	3.724103	11.59853	26.19701
2019-11-01	18.16978	4	17.30247	3.724103	10.87054	25.46902
2019-12-01	9.878288	6	17.01772	3.724103	2.579046	17.17753
2020-01-01	17.94764	4	18.31301	3.724103	10.64839	25.24688
2020-02-01	17.67965	4	20.4535	3.724103	10.38041	24.97889
2020-03-01	12.55237	5	17.00494	3.724103	5.253126	19.85161
2020-04-01	10.74856	4	9.751086	3.724103	3.449322	18.04781
2020-05-01	14.02028	5	17.95627	3.724103	6.721038	21.31952
2020-06-01	14.14831	4	14.03205	3.724103	6.849063	21.44755
2020-07-01	13.91748	4	14.74554	3.724103	6.618234	21.21672
2020-08-01	14.36976	5	16.05362	3.724103	7.070514	21.669
2020-09-01	18.96046	4	17.83735	3.724103	11.66121	26.2597
2020-10-01	22.11821	4	22.47506	3.724103	14.81897	29.41745
2020-11-01	21.50897	5	22.23723	3.724103	14.20973	28.80821
2020-12-01	13.35315	5	15.4497	3.724103	6.053913	20.6524
2021-01-01	21.55818	5	30.27885	3.724103	14.25894	28.85742
2021-02-01	21.40894	4	21.24214	3.724103	14.1097	28.70818
2021-03-01	22.06994	4	22.29838	3.724103	14.7707	29.36918
2021-04-01	21.23202	4	22.88518	3.724103	13.93278	28.53126
2021-05-01	20.85835	5	29.10525	3.724103	13.55911	28.15759
2021-06-01	17.34099	4	17.36926	3.724103	10.04175	24.64024
2021-07-01	14.99886	4	15.84358	3.724103	7.69962	22.2981
2021-08-01	15.45114	5	21.47686	3.724103	8.1519	22.75038
2021-09-01	20.04184	4	20.65534	3.724103	12.7426	27.34108
2021-10-01	23.2098	5	30.86565	3.724103	15.91056	30.50904
2021-11-01	22.60056	4	24.99765	3.724103	15.30131	29.8998
2021-12-01	14.43454	5	15.71044	3.724103	7.135299	21.73378
2022-01-01	22.63957	5	23.41166	3.724103	15.34033	29.93881
2022-02-01	22.49033	4	21.47021	3.724103	15.19108	29.78957

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	22.82703	5	29.1662	3.680151	15.61394	30.04013
2018-05-01	23.01765	4	22.42	3.680151	15.80456	30.23075
2018-06-01	19.68671	4	21.41009	3.680151	12.47361	26.8998
2018-07-01	15.27654	5	18.98631	3.680151	8.063447	22.48964
2018-08-01	14.79173	4	14.21953	3.680151	7.578639	22.00483
2018-09-01	18.73153	5	22.58159	3.680151	11.51843	25.94462
2018-10-01	23.52574	4	22.98555	3.680151	16.31264	30.73884
2018-11-01	23.54368	4	24.80339	3.680151	16.33058	30.75677
2018-12-01	13.5798	6	22.68314	3.680151	6.366704	20.79289
2019-01-01	21.39222	4	22.74335	3.680151	14.17913	28.60532
2019-02-01	22.06697	4	21.70045	3.680151	14.85387	29.28006
2019-03-01	22.09473	5	24.74894	3.680151	14.88163	29.30783
2019-04-01	21.97672	4	21.179	3.680151	14.76363	29.18982
2019-05-01	22.17529	4	22.58291	3.680151	14.9622	29.38839
2019-06-01	18.8364	5	19.97564	3.680151	11.6233	26.04949
2019-07-01	14.42623	4	14.36	3.680151	7.213139	21.63933
2019-08-01	13.94937	4	12.6352	3.680151	6.736277	21.16247
2019-09-01	17.88916	5	22.58291	3.680151	10.67607	25.10226
2019-10-01	22.68338	4	21.179	3.680151	15.47028	29.89647
2019-11-01	22.70132	4	22.94391	3.680151	15.48822	29.91441
2019-12-01	12.73744	6	19.9251	3.680151	5.524343	19.95053
2020-01-01	20.54986	4	22.78462	3.680151	13.33677	27.76296
2020-02-01	21.22461	4	21.1087	3.680151	14.01151	28.4377
2020-03-01	13.80495	5	19.19335	3.680151	6.59185	21.01804
2020-04-01	11.05695	4	11.49207	3.680151	3.843852	18.27004
2020-05-01	14.24965	5	16.36024	3.680151	7.036557	21.46275
2020-06-01	13.91285	4	15.04344	3.680151	6.699753	21.12594
2020-07-01	17.14982	4	17.07849	3.680151	9.936721	24.36291
2020-08-01	16.74658	5	21.82695	3.680151	9.533486	23.95968
2020-09-01	20.76795	4	19.7919	3.680151	13.55485	27.98104
2020-10-01	25.64262	4	24.85958	3.680151	18.42952	32.85571
2020-11-01	25.73418	5	30.28639	3.680151	18.52108	32.94727
2020-12-01	15.86094	5	18.35762	3.680151	8.647841	23.07403
2021-01-01	23.764	5	30.19159	3.680151	16.5509	30.97709
2021-02-01	24.51237	4	24.75311	3.680151	17.29927	31.72546
2021-03-01	24.62059	4	25.55289	3.680151	17.40749	31.83368
2021-04-01	24.58304	4	24.31323	3.680151	17.36994	31.79613
2021-05-01	24.85523	5	32.71089	3.680151	17.64213	32.06832
2021-06-01	21.59791	4	22.31379	3.680151	14.38481	28.811
2021-07-01	17.2682	4	17.51512	3.680151	10.0551	24.48129
2021-08-01	16.86496	5	22.07385	3.680151	9.651868	24.07806
2021-09-01	20.88633	4	22.47374	3.680151	13.67323	28.09942
2021-10-01	25.76211	5	35.03025	3.680151	18.54902	32.97521
2021-11-01	25.85368	4	26.2327	3.680151	18.64058	33.06677
2021-12-01	15.97932	5	18.31032	3.680151	8.766224	23.19241
2022-01-01	23.88238	5	25.78048	3.680151	16.66928	31.09547
2022-02-01	24.63075	4	24.87244	3.680151	17.41766	31.84385

Notes: All models included coefficients for the pre-pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Figure 1b : Descriptive text

Weekly hospitalization rate (per 100 000) with mental health and addiction diagnosis of male youth (10–17 years) in Canada (except Quebec) and in British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	7.641988088	5	9.620424391	1.000589507	5.680832654	9.603143521
2018-05-01	7.530964051	4	7.825225581	1.000589507	5.569808617	9.492119484
2018-06-01	7.118047285	4	7.226825978	1.000589507	5.156891852	9.079202719
2018-07-01	5.603525764	5	6.505677738	1.000589507	3.642370331	7.564681198
2018-08-01	5.646171134	4	5.262847793	1.000589507	3.6850157	7.607326567
2018-09-01	7.279293165	5	8.837901833	1.000589507	5.318137731	9.240448599
2018-10-01	7.51282953	4	8.116753593	1.000589507	5.551674097	9.473984964
2018-11-01	8.023624829	4	8.500343082	1.000589507	6.062469395	9.984780263
2018-12-01	5.256860992	6	7.518625392	1.000589507	3.295705558	7.218016425
2019-01-01	7.228530818	4	7.794135541	1.000589507	5.267375384	9.189686251
2019-02-01	7.364881171	4	7.173631547	1.000589507	5.403725738	9.326036605
2019-03-01	7.462573445	5	9.231888699	1.000589507	5.501418011	9.423728879
2019-04-01	7.446670267	4	7.158497303	1.000589507	5.485514834	9.407825701
2019-05-01	7.337471631	4	7.491450666	1.000589507	5.376316197	9.298627064
2019-06-01	6.922729465	5	8.278431342	1.000589507	4.961574031	8.883884898
2019-07-01	5.408207944	4	5.251582588	1.000589507	3.44705251	7.369363377
2019-08-01	5.452678714	4	5.009434688	1.000589507	3.49152328	7.413834147
2019-09-01	7.085800745	5	9.337828406	1.000589507	5.124645311	9.046956178
2019-10-01	7.31933711	4	6.976886378	1.000589507	5.358181676	9.280492543
2019-11-01	7.830132409	4	7.824404029	1.000589507	5.868976975	9.791287842
2019-12-01	5.063368572	6	7.737894313	1.000589507	3.102213138	7.024524005
2020-01-01	7.035038397	4	7.722522161	1.000589507	5.073882964	8.996193831
2020-02-01	7.171388751	4	6.975663151	1.000589507	5.210233318	9.132544185
2020-03-01	4.757006453	5	5.885248997	1.000589507	2.79585102	6.718161887
2020-04-01	3.860104049	4	4.062913013	1.000589507	1.898948616	5.821259483
2020-05-01	4.769573496	5	5.735877195	1.000589507	2.808418063	6.73072893
2020-06-01	5.375324815	4	5.481945132	1.000589507	3.414169381	7.336480248
2020-07-01	4.514119916	4	4.794834843	1.000589507	2.552964482	6.475275349
2020-08-01	4.56291295	5	6.542484925	1.000589507	2.601757516	6.524068383
2020-09-01	6.202182645	4	5.885248997	1.000589507	4.241027211	8.163338078
2020-10-01	6.443009001	4	5.646254114	1.000589507	4.481853567	8.404164434
2020-11-01	6.958126564	5	8.230386287	1.000589507	4.99697113	8.919281997
2020-12-01	4.198193464	5	5.076864337	1.000589507	2.237038031	6.159348898
2021-01-01	6.176694028	5	7.426282266	1.000589507	4.215538595	8.137849462
2021-02-01	6.317366646	4	6.639096346	1.000589507	4.356211212	8.278522079
2021-03-01	6.42234891	4	6.579686088	1.000589507	4.461193477	8.383504344
2021-04-01	6.413735723	4	6.431160443	1.000589507	4.452580289	8.374891156
2021-05-01	6.30885935	5	7.663923299	1.000589507	4.347703917	8.270014784
2021-06-01	5.900264849	4	6.059846329	1.000589507	3.939109415	7.861420282
2021-07-01	4.393033318	4	4.767673215	1.000589507	2.431877885	6.354188752
2021-08-01	4.441826352	5	5.540006571	1.000589507	2.480670919	6.402981786
2021-09-01	6.081096047	4	6.178666846	1.000589507	4.119940614	8.042251481
2021-10-01	6.320780077	5	8.436256655	1.000589507	4.359624643	8.28193551
2021-11-01	6.83589764	4	6.832179685	1.000589507	4.874742206	8.797053073
2021-12-01	4.077106867	5	5.49108572	1.000589507	2.115951433	6.038262301
2022-01-01	6.055607431	5	6.611006073	1.000589507	4.094451997	8.016762864
2022-02-01	6.196280049	4	6.261525576	1.000589507	4.235124615	8.157435482

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	10.78959	5	13.21882	2.483882	5.921184	15.658
2018-05-01	9.858466	4	10.62447	2.483882	4.990058	14.72687
2018-06-01	9.793699	4	10.99509	2.483882	4.925291	14.66211
2018-07-01	7.933366	5	9.759689	2.483882	3.064958	12.80177
2018-08-01	7.239744	4	9.389068	2.483882	2.371336	12.10815
2018-09-01	10.25242	5	11.61279	2.483882	5.384016	15.12083
2018-10-01	9.917261	4	11.24217	2.483882	5.048852	14.78567
2018-11-01	11.1588	4	11.61279	2.483882	6.290395	16.02721
2018-12-01	7.848572	6	10.36579	2.483882	2.980164	12.71698
2019-01-01	10.80447	4	9.805892	2.483882	5.936064	15.67288
2019-02-01	11.43799	4	10.54133	2.483882	6.569584	16.3064
2019-03-01	11.04266	5	12.01222	2.483882	6.174253	15.91107
2019-04-01	11.79514	4	9.560745	2.483882	6.926735	16.66355
2019-05-01	10.85462	4	10.78648	2.483882	5.986211	15.72303
2019-06-01	10.79925	5	13.36053	2.483882	5.930842	15.66766
2019-07-01	8.938917	4	10.29619	2.483882	4.070509	13.80733
2019-08-01	8.235898	4	7.476993	2.483882	3.36749	13.10431
2019-09-01	11.24858	5	15.19913	2.483882	6.380169	16.11699
2019-10-01	10.91341	4	9.805892	2.483882	6.045006	15.78182
2019-11-01	12.15496	4	11.76707	2.483882	7.286549	17.02336
2019-12-01	8.844725	6	13.83743	2.483882	3.976317	13.71313
2020-01-01	11.80063	4	13.36976	2.483882	6.932218	16.66903
2020-02-01	12.43415	4	11.7897	2.483882	7.565737	17.30255
2020-03-01	8.639705	5	12.15433	2.483882	3.771297	13.50811
2020-04-01	7.988351	4	8.386488	2.483882	3.119943	12.85676
2020-05-01	8.165815	5	9.723465	2.483882	3.297407	13.03422
2020-06-01	9.219035	4	9.480378	2.483882	4.350627	14.08744
2020-07-01	8.161816	4	6.320252	2.483882	3.293408	13.03022
2020-08-01	7.360437	5	9.723465	2.483882	2.492029	12.22885
2020-09-01	10.26536	4	10.9389	2.483882	5.396951	15.13377
2020-10-01	9.825013	4	9.480378	2.483882	4.956605	14.69342
2020-11-01	10.9682	5	13.49131	2.483882	6.099788	15.8366
2020-12-01	7.538234	5	9.967499	2.483882	2.669826	12.40664
2021-01-01	10.3744	5	13.03892	2.483882	5.505995	15.24281
2021-02-01	10.90956	4	11.57661	2.483882	6.041154	15.77797
2021-03-01	10.40905	4	10.84546	2.483882	5.540641	15.27746
2021-04-01	11.05635	4	13.16078	2.483882	6.187941	15.92476
2021-05-01	10.01747	5	12.30777	2.483882	5.149057	14.88587
2021-06-01	9.854338	4	8.530136	2.483882	4.98593	14.72275
2021-07-01	7.888823	4	8.530136	2.483882	3.020415	12.75723
2021-08-01	7.087444	5	6.945968	2.483882	2.219036	11.95585
2021-09-01	9.992365	4	9.383149	2.483882	5.123957	14.86077
2021-10-01	9.549444	5	12.06405	2.483882	4.681036	14.41785
2021-11-01	10.69263	4	10.84546	2.483882	5.824219	15.56103
2021-12-01	7.26524	5	9.373571	2.483882	2.396832	12.13365
2022-01-01	10.10141	5	11.98529	2.483882	5.233001	14.96982
2022-02-01	10.63657	4	11.51062	2.483882	5.768161	15.50498

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	9.070368	5	13.31746	2.088674	4.976566	13.16417
2018-05-01	9.234462	4	9.838127	2.088674	5.14066	13.32826
2018-06-01	8.518208	4	7.438584	2.088674	4.424406	12.61201
2018-07-01	6.706642	5	8.158447	2.088674	2.612841	10.80044
2018-08-01	7.627485	4	7.438584	2.088674	3.533683	11.72129
2018-09-01	9.631904	5	11.0379	2.088674	5.538102	13.72571
2018-10-01	9.133504	4	9.598173	2.088674	5.039702	13.22731
2018-11-01	9.277757	4	8.518378	2.088674	5.183955	13.37156
2018-12-01	6.09988	6	10.16539	2.088674	2.006078	10.19368
2019-01-01	9.298096	4	9.360579	2.088674	5.204294	13.3919
2019-02-01	9.295899	4	9.243572	2.088674	5.202097	13.3897
2019-03-01	8.671931	5	10.99868	2.088674	4.578129	12.76573
2019-04-01	8.906093	4	8.073499	2.088674	4.812291	12.9999
2019-05-01	9.071722	4	7.488463	2.088674	4.97792	13.16552
2019-06-01	8.353933	5	9.594593	2.088674	4.260131	12.44774
2019-07-01	6.542368	4	6.78642	2.088674	2.448566	10.63617
2019-08-01	7.464745	4	7.60547	2.088674	3.370943	11.55855
2019-09-01	9.469164	5	11.93474	2.088674	5.375362	13.56297
2019-10-01	8.970764	4	8.89255	2.088674	4.876962	13.06457
2019-11-01	9.115017	4	10.29664	2.088674	5.021215	13.20882
2019-12-01	5.937141	6	8.178707	2.088674	1.843339	10.03094
2020-01-01	9.135357	4	10.49328	2.088674	5.041555	13.22916
2020-02-01	9.133159	4	9.238644	2.088674	5.039357	13.22696
2020-03-01	6.358222	5	8.326186	2.088674	2.26442	10.45202
2020-04-01	5.461037	4	5.13258	2.088674	1.367235	9.554839
2020-05-01	6.014228	5	7.29967	2.088674	1.920426	10.10803
2020-06-01	5.685537	4	5.816924	2.088674	1.591735	9.779339
2020-07-01	6.140862	4	6.045039	2.088674	2.04706	10.23466
2020-08-01	6.986552	5	9.124587	2.088674	2.89275	11.08035
2020-09-01	8.91582	4	10.60733	2.088674	4.822018	13.00962
2020-10-01	8.352154	4	7.755899	2.088674	4.258352	12.44596
2020-11-01	8.41972	5	10.72139	2.088674	4.325918	12.51352
2020-12-01	5.158342	5	5.353999	2.088674	1.06454	9.252144
2021-01-01	8.273056	5	9.327813	2.088674	4.179254	12.36686
2021-02-01	8.194172	4	7.754447	2.088674	4.10037	12.28797
2021-03-01	7.504938	4	6.967764	2.088674	3.411136	11.59874
2021-04-01	7.673834	4	6.855381	2.088674	3.580032	11.76764
2021-05-01	7.762776	5	10.90118	2.088674	3.668974	11.85658
2021-06-01	6.969836	4	8.765897	2.088674	2.876034	11.06364
2021-07-01	5.093004	4	5.169631	2.088674	0.999202	9.186806
2021-08-01	5.938695	5	7.080147	2.088674	1.844893	10.0325
2021-09-01	7.867962	4	7.080147	2.088674	3.77416	11.96176
2021-10-01	7.294411	5	9.327813	2.088674	3.200609	11.38821
2021-11-01	7.361978	4	6.742997	2.088674	3.268176	11.45578
2021-12-01	4.110485	5	5.94347	2.088674	0.016683	8.204287
2022-01-01	7.225199	5	8.624605	2.088674	3.131397	11.319
2022-02-01	7.146315	4	7.532883	2.088674	3.052513	11.24012

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	9.281951	5	11.52791	1.441156	6.457286	12.10662
2018-05-01	9.023497	4	9.354297	1.441156	6.198832	11.84816
2018-06-01	8.201021	4	8.849709	1.441156	5.376356	11.02569
2018-07-01	6.486048	5	7.219499	1.441156	3.661383	9.310713
2018-08-01	6.352759	4	5.16233	1.441156	3.528094	9.177424
2018-09-01	8.356916	5	10.47992	1.441156	5.532251	11.18158
2018-10-01	9.163463	4	9.315483	1.441156	6.338798	11.98813
2018-11-01	9.833849	4	10.40229	1.441156	7.009184	12.65851
2018-12-01	6.29827	6	8.917968	1.441156	3.473605	9.122935
2019-01-01	8.447628	4	9.756	1.441156	5.622963	11.27229
2019-02-01	8.802244	4	8.444917	1.441156	5.977579	11.62691
2019-03-01	8.603678	5	10.83572	1.441156	5.779013	11.42834
2019-04-01	8.783012	4	9.177581	1.441156	5.958347	11.60768
2019-05-01	8.52922	4	9.640316	1.441156	5.704555	11.35389
2019-06-01	7.702082	5	8.714846	1.441156	4.877417	10.52675
2019-07-01	5.987108	4	5.437138	1.441156	3.162443	8.811773
2019-08-01	5.858482	4	5.012964	1.441156	3.033817	8.683147
2019-09-01	7.86264	5	10.21873	1.441156	5.037975	10.6873
2019-10-01	8.669186	4	8.791968	1.441156	5.844521	11.49385
2019-11-01	9.339573	4	9.331826	1.441156	6.514908	12.16424
2019-12-01	5.803993	6	8.59444	1.441156	2.979328	8.628658
2020-01-01	7.953351	4	8.55866	1.441156	5.128686	10.77802
2020-02-01	8.307968	4	8.443521	1.441156	5.483303	11.13263
2020-03-01	5.043309	5	5.795326	1.441156	2.218644	7.867974
2020-04-01	4.279623	4	4.605557	1.441156	1.454958	7.104288
2020-05-01	5.436795	5	6.332641	1.441156	2.61213	8.26146
2020-06-01	6.025282	4	6.255882	1.441156	3.200618	8.849947
2020-07-01	4.865441	4	5.756946	1.441156	2.040776	7.690106
2020-08-01	4.781433	5	7.445651	1.441156	1.956768	7.606098
2020-09-01	6.834872	4	5.526668	1.441156	4.010207	9.659537
2020-10-01	7.689887	4	6.601298	1.441156	4.865222	10.51455
2020-11-01	8.404892	5	10.01709	1.441156	5.580227	11.22956
2020-12-01	4.924069	5	6.064602	1.441156	2.099404	7.748734
2021-01-01	7.128185	5	8.458636	1.441156	4.30352	9.95285
2021-02-01	7.52742	4	7.958808	1.441156	4.702755	10.35208
2021-03-01	7.377322	4	7.805015	1.441156	4.552657	10.20199
2021-04-01	7.605124	4	6.959151	1.441156	4.780459	10.42979
2021-05-01	7.395951	5	8.266395	1.441156	4.571286	10.22062
2021-06-01	6.618094	4	6.651564	1.441156	3.793429	9.442759
2021-07-01	4.951589	4	5.498114	1.441156	2.126924	7.776254
2021-08-01	4.867581	5	6.651564	1.441156	2.042916	7.692246
2021-09-01	6.92102	4	7.805015	1.441156	4.096355	9.745685
2021-10-01	7.776848	5	10.53485	1.441156	4.952183	10.60151
2021-11-01	8.491853	4	8.420188	1.441156	5.667188	11.31652
2021-12-01	5.010218	5	6.994244	1.441156	2.185553	7.834883
2022-01-01	7.214333	5	7.55583	1.441156	4.389668	10.039
2022-02-01	7.613568	4	7.403954	1.441156	4.788903	10.43823

Notes: All models included coefficients for the pre-pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Changes in self-harm–related inpatient hospitalizations

The self-harm–related hospitalization rate during T0 was higher for females than for males for all provinces; the national rate for the entire cohort was 1.90 (95% CI: 1.76 to 2.04) weekly events per 100 000 persons, and rates remained stable during this time (Table 2). During T1, the rates also remained stable for the entire cohort. There was a statistically significant increasing trend in the national rate of hospitalizations of females during T2, as well as for British Columbia, Ontario, Alberta and the Atlantic provinces, from highest to lowest rate of increase (Figures 2a and 2b; graphical data not shown for Atlantic provinces); we observed no statistically significant change in trend for males. At the national level, the level rate for females increased from 3.18 (95% CI: 2.92 to 3.44) in T0 to 3.79 (95% CI: 3.42 to 4.16) events per 100 000 persons in T2, equating to a 19% (95% CI: 7% to 31%) increase. We also found a statistically significant increasing trend in rates for females aged 10 to 14 years and 15 to 17 years. However, the level change was only statistically significant for females aged 10 to 14 years; the rate increased from 1.85 (95% CI: 1.66 to 2.03) in T0 to 2.46 (95% CI: 2.16 to 2.76) events per 100 000 persons in T2, equating to a 32% (95% CI: 16% to 49%) increase.

Figure 2a : Descriptive text

Weekly hospitalization rate (per 100 000) with self-harm diagnosis of female youth (10–17 years) in Canada (except Quebec) and in British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	3.168468385	5	4.244739555	0.59105031	2.010009778	4.326926993
2018-05-01	3.218115635	4	2.856422482	0.59105031	2.059657027	4.376574243
2018-06-01	2.767478122	4	2.728761142	0.59105031	1.609019514	3.92593673
2018-07-01	1.973889828	5	2.48939613	0.59105031	0.81543122	3.132348436
2018-08-01	2.05262324	4	2.122369777	0.59105031	0.894164632	3.211081848
2018-09-01	2.676315737	5	3.335152507	0.59105031	1.51785713	3.834774345
2018-10-01	2.950685295	4	3.111745162	0.59105031	1.792226687	4.109143903
2018-11-01	3.012643737	4	2.87238015	0.59105031	1.85418513	4.171102345
2018-12-01	1.819053809	6	3.42309652	0.59105031	0.660595201	2.977512416
2019-01-01	2.856137929	4	3.081363724	0.59105031	1.697679321	4.014596536
2019-02-01	3.0752546	4	2.908430045	0.59105031	1.916795992	4.233713208
2019-03-01	2.91293192	5	3.191412428	0.59105031	1.754473312	4.071390528
2019-04-01	2.973184201	4	2.546841445	0.59105031	1.814725594	4.131642809
2019-05-01	3.024656537	4	2.892708802	0.59105031	1.866197929	4.183115145
2019-06-01	2.572193938	5	2.876987558	0.59105031	1.41373533	3.730652546
2019-07-01	1.778605644	4	1.776500514	0.59105031	0.620147036	2.937064252
2019-08-01	1.859164142	4	1.902270462	0.59105031	0.700705534	3.017622749
2019-09-01	2.482856639	5	3.191412428	0.59105031	1.324398031	3.641315247
2019-10-01	2.757226197	4	2.782660097	0.59105031	1.598767589	3.915684805
2019-11-01	2.819184639	4	2.924151289	0.59105031	1.660726032	3.977643247
2019-12-01	1.62559471	6	2.54304847	0.59105031	0.467136103	2.784053318
2020-01-01	2.66267883	4	3.009041394	0.59105031	1.504220223	3.821137438
2020-02-01	2.881795502	4	3.009041394	0.59105031	1.723336894	4.04025411
2020-03-01	2.135857324	5	2.419641533	0.59105031	0.977398716	3.294315932
2020-04-01	1.930315264	4	2.10943108	0.59105031	0.771856656	3.088773872
2020-05-01	2.138468787	5	2.326578397	0.59105031	0.980010179	3.296927395
2020-06-01	1.844512462	4	2.031878467	0.59105031	0.686053854	3.00297107
2020-07-01	2.237130822	4	2.419641533	0.59105031	1.078672214	3.39558943
2020-08-01	2.380867871	5	2.590257282	0.59105031	1.222409264	3.539326479
2020-09-01	3.069564007	4	2.962509826	0.59105031	1.911105399	4.228022615
2020-10-01	3.403539662	4	3.288230802	0.59105031	2.245081054	4.56199827
2020-11-01	3.528676657	5	4.048246411	0.59105031	2.370218049	4.687135265
2020-12-01	2.407312992	5	2.542614358	0.59105031	1.248854385	3.5657716
2021-01-01	3.516623377	5	4.565809981	0.59105031	2.358164769	4.675081985
2021-02-01	3.798918601	4	3.809983329	0.59105031	2.640459993	4.957377208
2021-03-01	3.696202018	4	4.39613461	0.59105031	2.53774341	4.854660626
2021-04-01	3.816060397	4	3.779133261	0.59105031	2.657601789	4.974519004
2021-05-01	3.930711284	5	5.753537577	0.59105031	2.772252677	5.089169892
2021-06-01	3.543252324	4	3.73285816	0.59105031	2.384793716	4.701710931
2021-07-01	2.809270127	4	2.606830699	0.59105031	1.650811519	3.967728735
2021-08-01	2.953007177	5	3.964233666	0.59105031	1.794548569	4.111465785
2021-09-01	3.641703312	4	3.671158025	0.59105031	2.483244705	4.80016192
2021-10-01	3.981076508	5	4.905160723	0.59105031	2.8226179	5.139535116
2021-11-01	4.106213503	4	4.504109846	0.59105031	2.947754895	5.264672111
2021-12-01	2.979452298	5	3.391670037	0.59105031	1.82099369	4.137910906
2022-01-01	4.088762682	5	4.369334228	0.59105031	2.930304075	5.24722129
2022-02-01	4.371057906	4	4.399571835	0.59105031	3.212599298	5.529516514

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	5.747712	5	6.795813	1.778309	2.262225	9.233198
2018-05-01	5.629448	4	4.103132	1.778309	2.143961	9.114934
2018-06-01	3.930312	4	4.487801	1.778309	0.444826	7.415798
2018-07-01	2.820543	5	3.462018	1.778309	-0.66494	6.306029
2018-08-01	3.128639	4	4.359578	1.778309	-0.35685	6.614126
2018-09-01	4.242223	5	5.000692	1.778309	0.756737	7.72771
2018-10-01	4.356629	4	4.616024	1.778309	0.871142	7.842115
2018-11-01	5.277367	4	4.744247	1.778309	1.791881	8.762853
2018-12-01	2.950355	6	5.379929	1.778309	-0.53513	6.435841
2019-01-01	5.211861	4	5.594007	1.778309	1.726374	8.697347
2019-02-01	4.949569	4	5.085461	1.778309	1.464083	8.435055
2019-03-01	5.827687	5	6.992509	1.778309	2.3422	9.313173
2019-04-01	5.864318	4	5.594007	1.778309	2.378832	9.349804
2019-05-01	5.744964	4	4.576915	1.778309	2.259478	9.23045
2019-06-01	4.046918	5	4.704052	1.778309	0.561432	7.532405
2019-07-01	2.937149	4	3.686959	1.778309	-0.54834	6.422636
2019-08-01	3.244156	4	4.068369	1.778309	-0.24133	6.729642
2019-09-01	4.35774	5	6.102553	1.778309	0.872254	7.843226
2019-10-01	4.472145	4	4.195505	1.778309	0.986659	7.957631
2019-11-01	5.392884	4	5.975417	1.778309	1.907397	8.87837
2019-12-01	3.065872	6	4.57278	1.778309	-0.41961	6.551358
2020-01-01	5.327377	4	5.92683	1.778309	1.841891	8.812864
2020-02-01	5.065085	4	4.035289	1.778309	1.579599	8.550572
2020-03-01	4.093696	5	4.413597	1.778309	0.60821	7.579182
2020-04-01	3.472399	4	3.909186	1.778309	-0.01309	6.957885
2020-05-01	4.093518	5	4.287494	1.778309	0.608032	7.579004
2020-06-01	3.134855	4	3.530878	1.778309	-0.35063	6.620342
2020-07-01	3.865187	4	3.278672	1.778309	0.379701	7.350673
2020-08-01	4.293623	5	4.665802	1.778309	0.808136	7.779109
2020-09-01	5.527546	4	5.422419	1.778309	2.04206	9.013032
2020-10-01	5.74783	4	5.044111	1.778309	2.262344	9.233316
2020-11-01	6.789998	5	7.313961	1.778309	3.304511	10.27548
2020-12-01	4.596696	5	6.179135	1.778309	1.11121	8.082183
2021-01-01	6.991912	5	9.839887	1.778309	3.506426	10.4774
2021-02-01	6.85105	4	7.064535	1.778309	3.365563	10.33654
2021-03-01	7.835046	4	8.830668	1.778309	4.34956	11.32053
2021-04-01	7.977556	4	8.199906	1.778309	4.49207	11.46304
2021-05-01	7.979632	5	13.49831	1.778309	4.494145	11.46512
2021-06-01	6.401925	4	5.803011	1.778309	2.916439	9.887412
2021-07-01	5.398035	4	5.298401	1.778309	1.912549	8.883521
2021-08-01	5.826471	5	5.929163	1.778309	2.340985	9.311957
2021-09-01	7.060394	4	6.81223	1.778309	3.574908	10.54588
2021-10-01	7.295139	5	9.839887	1.778309	3.809653	10.78063
2021-11-01	8.337307	4	9.46143	1.778309	4.85182	11.82279
2021-12-01	6.129544	5	6.300297	1.778309	2.644058	9.615031
2022-01-01	8.524761	5	8.574354	1.778309	5.039274	12.01025
2022-02-01	8.383898	4	9.064317	1.778309	4.898412	11.86938

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	3.411014	5	5.004805	1.418484	0.630784	6.191243
2018-05-01	3.448591	4	3.002883	1.418484	0.668362	6.22882
2018-06-01	3.36224	4	2.627522	1.418484	0.582011	6.14247
2018-07-01	3.058547	5	3.878724	1.418484	0.278317	5.838776
2018-08-01	2.792532	4	2.627522	1.418484	0.012302	5.572761
2018-09-01	3.639686	5	5.004805	1.418484	0.859457	6.419915
2018-10-01	3.338141	4	2.877763	1.418484	0.557912	6.11837
2018-11-01	3.743782	4	3.878724	1.418484	0.963553	6.524011
2018-12-01	2.161665	6	3.111644	1.418484	-0.61856	4.941894
2019-01-01	3.561937	4	4.020997	1.418484	0.781708	6.342167
2019-02-01	3.135276	4	3.7773	1.418484	0.355047	5.915505
2019-03-01	3.613686	5	5.483178	1.418484	0.833456	6.393915
2019-04-01	3.135397	4	2.558816	1.418484	0.355168	5.915626
2019-05-01	3.17555	4	2.558816	1.418484	0.395321	5.955779
2019-06-01	3.086624	5	3.899149	1.418484	0.306394	5.866853
2019-07-01	2.78293	4	2.436968	1.418484	0.002701	5.563159
2019-08-01	2.519491	4	2.193271	1.418484	-0.26074	5.29972
2019-09-01	3.366645	5	4.020997	1.418484	0.586416	6.146874
2019-10-01	3.0651	4	2.924361	1.418484	0.284871	5.845329
2019-11-01	3.470741	4	2.924361	1.418484	0.690512	6.25097
2019-12-01	1.888624	6	3.15926	1.418484	-0.89161	4.668853
2020-01-01	3.288896	4	4.162049	1.418484	0.508667	6.069126
2020-02-01	2.862235	4	3.56747	1.418484	0.082006	5.642465
2020-03-01	2.597995	5	2.378314	1.418484	-0.18223	5.378224
2020-04-01	1.887222	4	2.497229	1.418484	-0.89301	4.667451
2020-05-01	2.262448	5	1.902651	1.418484	-0.51778	5.042678
2020-06-01	2.511171	4	2.972892	1.418484	-0.26906	5.2914
2020-07-01	2.658564	4	3.686386	1.418484	-0.12167	5.438793
2020-08-01	2.501727	5	2.378314	1.418484	-0.2785	5.281956
2020-09-01	3.458059	4	2.497229	1.418484	0.67783	6.238288
2020-10-01	3.256137	4	3.924217	1.418484	0.475908	6.036366
2020-11-01	3.76838	5	4.162049	1.418484	0.988151	6.54861
2020-12-01	2.307572	5	2.735061	1.418484	-0.47266	5.087801
2021-01-01	3.829153	5	5.281194	1.418484	1.048924	6.609383
2021-02-01	3.509094	4	2.229838	1.418484	0.728865	6.289324
2021-03-01	4.087127	4	3.990236	1.418484	1.306898	6.867356
2021-04-01	3.708461	4	2.933997	1.418484	0.928232	6.48869
2021-05-01	3.855217	5	6.806873	1.418484	1.074987	6.635446
2021-06-01	3.875468	4	4.107596	1.418484	1.095239	6.655697
2021-07-01	3.671397	4	2.933997	1.418484	0.891168	6.451626
2021-08-01	3.51456	5	5.633274	1.418484	0.734331	6.294789
2021-09-01	4.470892	4	5.163834	1.418484	1.690663	7.251122
2021-10-01	4.278526	5	5.281194	1.418484	1.498296	7.058755
2021-11-01	4.790769	4	5.750634	1.418484	2.01054	7.570998
2021-12-01	3.320405	5	4.104439	1.418484	0.540176	6.100634
2022-01-01	4.841987	5	4.225519	1.418484	2.061758	7.622216
2022-02-01	4.521928	4	4.453926	1.418484	1.741699	7.302157

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	2.979033	5	4.241622	0.817353	1.377022	4.581045
2018-05-01	2.972961	4	2.787352	0.817353	1.370949	4.574972
2018-06-01	2.737214	4	3.02973	0.817353	1.135202	4.339225
2018-07-01	1.717902	5	2.060216	0.817353	0.11589	3.319914
2018-08-01	1.683751	4	1.979424	0.817353	0.08174	3.285763
2018-09-01	2.296865	5	2.746955	0.817353	0.694853	3.898877
2018-10-01	3.087381	4	3.231712	0.817353	1.485369	4.689393
2018-11-01	3.042874	4	3.110523	0.817353	1.440862	4.644886
2018-12-01	1.677048	6	3.268408	0.817353	0.075037	3.27906
2019-01-01	2.733029	4	2.687486	0.817353	1.131017	4.335041
2019-02-01	3.207961	4	2.527039	0.817353	1.60595	4.809973
2019-03-01	2.718688	5	2.366592	0.817353	1.116676	4.3207
2019-04-01	2.873048	4	2.647375	0.817353	1.271036	4.47506
2019-05-01	2.867966	4	2.446816	0.817353	1.265954	4.469978
2019-06-01	2.631228	5	2.607263	0.817353	1.029217	4.23324
2019-07-01	1.611917	4	1.764916	0.817353	0.009905	3.213929
2019-08-01	1.578757	4	1.243464	0.817353	-0.02326	3.180768
2019-09-01	2.19187	5	3.00838	0.817353	0.589859	3.793882
2019-10-01	2.982386	4	2.807821	0.817353	1.380375	4.584398
2019-11-01	2.937879	4	3.369386	0.817353	1.335867	4.539891
2019-12-01	1.572054	6	2.725928	0.817353	-0.02996	3.174066
2020-01-01	2.628034	4	2.952823	0.817353	1.026023	4.230046
2020-02-01	3.102967	4	3.471563	0.817353	1.500955	4.704979
2020-03-01	2.122348	5	2.553793	0.817353	0.520337	3.72436
2020-04-01	2.098612	4	2.154763	0.817353	0.4966	3.700623
2020-05-01	2.28471	5	2.91292	0.817353	0.682698	3.886722
2020-06-01	2.240144	4	2.234569	0.817353	0.638132	3.842156
2020-07-01	2.428908	4	2.593696	0.817353	0.826896	4.030919
2020-08-01	2.444509	5	2.793211	0.817353	0.842497	4.046521
2020-09-01	3.107375	4	3.192242	0.817353	1.505363	4.709386
2020-10-01	3.943105	4	3.83069	0.817353	2.341093	5.545117
2020-11-01	3.947359	5	4.469138	0.817353	2.345348	5.549371
2020-12-01	2.636814	5	2.514577	0.817353	1.034802	4.238826
2021-01-01	3.748075	5	4.638709	0.817353	2.146063	5.350086
2021-02-01	4.271768	4	4.638709	0.817353	2.669757	5.87378
2021-03-01	3.82771	4	4.95862	0.817353	2.225698	5.429721
2021-04-01	4.027284	4	3.678976	0.817353	2.425272	5.629296
2021-05-01	4.070963	5	5.63843	0.817353	2.468952	5.672975
2021-06-01	3.883978	4	4.278809	0.817353	2.281966	5.48599
2021-07-01	2.909881	4	2.679254	0.817353	1.307869	4.511893
2021-08-01	2.925482	5	3.958898	0.817353	1.32347	4.527494
2021-09-01	3.588348	4	3.359065	0.817353	1.986336	5.19036
2021-10-01	4.428616	5	5.678419	0.817353	2.826604	6.030628
2021-11-01	4.43287	4	4.398775	0.817353	2.830858	6.034882
2021-12-01	3.117787	5	3.557992	0.817353	1.515775	4.719799
2022-01-01	4.229048	5	5.053448	0.817353	2.627036	5.83106
2022-02-01	4.752742	4	4.698128	0.817353	3.15073	6.354753

Notes: All models included coefficients for the pre-COVID-19 pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Figure 2b : Descriptive text

Weekly hospitalization rates (per 100 000) with self-harm diagnosis of male youth (10–17 years) in Canada (except Quebec) and in British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	0.66946108	5	0.675117501	0.185762774	0.305366042	1.033556117
2018-05-01	0.666223883	4	0.797866138	0.185762774	0.302128845	1.030318921
2018-06-01	0.623534797	4	0.583056024	0.185762774	0.259439759	0.987629834
2018-07-01	0.468092076	5	0.460307387	0.185762774	0.103997038	0.832187114
2018-08-01	0.403173571	4	0.398933069	0.185762774	0.039078533	0.767268608
2018-09-01	0.535091754	5	0.690461081	0.185762774	0.170996717	0.899186792
2018-10-01	0.57661074	4	0.659773922	0.185762774	0.212515702	0.940705777
2018-11-01	0.642174867	4	0.70580466	0.185762774	0.278079829	1.006269904
2018-12-01	0.415129542	6	0.597143588	0.185762774	0.051034504	0.77922458
2019-01-01	0.48012542	4	0.68104097	0.185762774	0.116030382	0.844220458
2019-02-01	0.637084724	4	0.741577945	0.185762774	0.272989687	1.001179762
2019-03-01	0.526942268	5	0.665906726	0.185762774	0.162847231	0.891037306
2019-04-01	0.616134739	4	0.620503995	0.185762774	0.252039701	0.980229777
2019-05-01	0.613395919	4	0.605369751	0.185762774	0.249300882	0.977490957
2019-06-01	0.570208456	5	0.469161557	0.185762774	0.206113418	0.934303494
2019-07-01	0.414765736	4	0.484295801	0.185762774	0.050670698	0.778860773
2019-08-01	0.350345607	4	0.257282144	0.185762774	-0.013749431	0.714440645
2019-09-01	0.482263791	5	0.529698532	0.185762774	0.118168753	0.846358829
2019-10-01	0.523782776	4	0.438893069	0.185762774	0.159687738	0.887877814
2019-11-01	0.589346903	4	0.590235507	0.185762774	0.225251865	0.953441941
2019-12-01	0.362301578	6	0.665315535	0.185762774	-0.001793459	0.726396616
2020-01-01	0.427297456	4	0.433178226	0.185762774	0.063202418	0.791392494
2020-02-01	0.584256761	4	0.597487208	0.185762774	0.220161723	0.948351799
2020-03-01	0.315546997	5	0.448115406	0.185762774	-0.048548041	0.679642035
2020-04-01	0.328850087	4	0.343555144	0.185762774	-0.03524495	0.692945125
2020-05-01	0.363955666	5	0.373429505	0.185762774	-0.000139372	0.728050704
2020-06-01	0.359110978	4	0.403303865	0.185762774	-0.00498406	0.723206016
2020-07-01	0.42815164	4	0.582550028	0.185762774	0.064056602	0.792246678
2020-08-01	0.367525412	5	0.582550028	0.185762774	0.003430374	0.73162045
2020-09-01	0.503735873	4	0.388366685	0.185762774	0.139640835	0.867830911
2020-10-01	0.549568593	4	0.463052586	0.185762774	0.185473555	0.913663631
2020-11-01	0.61892662	5	0.687110289	0.185762774	0.254831582	0.983021658
2020-12-01	0.396650493	5	0.298658988	0.185762774	0.032555455	0.76074553
2021-01-01	0.466415567	5	0.504987194	0.185762774	0.102320529	0.830510605
2021-02-01	0.627168772	4	0.668365404	0.185762774	0.263073734	0.99126381
2021-03-01	0.521340051	4	0.460429501	0.185762774	0.157245013	0.885435089
2021-04-01	0.614846256	4	0.757480791	0.185762774	0.250751218	0.978941294
2021-05-01	0.615901337	5	0.727775662	0.185762774	0.251806299	0.979996375
2021-06-01	0.577006151	4	0.816891049	0.185762774	0.212911113	0.941101189
2021-07-01	0.425877165	4	0.32675642	0.185762774	0.061782127	0.789972203
2021-08-01	0.365250937	5	0.430724371	0.185762774	0.001155899	0.729345974
2021-09-01	0.501461398	4	0.668365404	0.185762774	0.13736636	0.865556436
2021-10-01	0.54727266	5	0.772333356	0.185762774	0.183177622	0.911367698
2021-11-01	0.616630687	4	0.638660275	0.185762774	0.25253565	0.980725725
2021-12-01	0.394376017	5	0.593811704	0.185762774	0.030280979	0.758471055
2022-01-01	0.464141092	5	0.451412309	0.185762774	0.100046054	0.82823613
2022-02-01	0.624894297	4	0.465973996	0.185762774	0.260799259	0.988989335

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	1.235675	5	1.235404	0.650505	-0.03932	2.510666
2018-05-01	1.322835	4	1.853106	0.650505	0.047845	2.597826
2018-06-01	0.943952	4	0.617702	0.650505	-0.33104	2.218943
2018-07-01	0.989815	5	0.494161	0.650505	-0.28518	2.264805
2018-08-01	0.917589	4	0.864783	0.650505	-0.3574	2.19258
2018-09-01	1.030757	5	1.729565	0.650505	-0.24423	2.305747
2018-10-01	1.105759	4	1.606025	0.650505	-0.16923	2.38075
2018-11-01	1.0437	4	0.988323	0.650505	-0.23129	2.31869
2018-12-01	0.717794	6	0.617702	0.650505	-0.5572	1.992784
2019-01-01	0.84305	4	1.225737	0.650505	-0.43194	2.11804
2019-02-01	1.44756	4	1.961178	0.650505	0.172569	2.72255
2019-03-01	0.807269	5	1.225737	0.650505	-0.46772	2.082259
2019-04-01	1.118741	4	0.735442	0.650505	-0.15625	2.393731
2019-05-01	1.206994	4	1.470884	0.650505	-0.068	2.481984
2019-06-01	0.827018	5	0.490295	0.650505	-0.44797	2.102009
2019-07-01	0.87288	4	1.593458	0.650505	-0.40211	2.147871
2019-08-01	0.801748	4	0.858016	0.650505	-0.47324	2.076738
2019-09-01	0.914916	5	0.612868	0.650505	-0.36007	2.189906
2019-10-01	0.989918	4	0.735442	0.650505	-0.28507	2.264908
2019-11-01	0.927859	4	0.735442	0.650505	-0.34713	2.202849
2019-12-01	0.601953	6	1.103163	0.650505	-0.67304	1.876943
2020-01-01	0.727208	4	0.607717	0.650505	-0.54778	2.002199
2020-02-01	1.331718	4	1.215433	0.650505	0.056728	2.606709
2020-03-01	0.484508	5	0.972346	0.650505	-0.79048	1.759498
2020-04-01	0.70372	4	0.850803	0.650505	-0.57127	1.97871
2020-05-01	0.84962	5	0.486173	0.650505	-0.42537	2.12461
2020-06-01	0.528383	4	0.850803	0.650505	-0.74661	1.803374
2020-07-01	0.698988	4	0.607717	0.650505	-0.576	1.973978
2020-08-01	0.65036	5	1.09389	0.650505	-0.62463	1.92535
2020-09-01	0.787125	4	0.72926	0.650505	-0.48787	2.062115
2020-10-01	0.884195	4	0.607717	0.650505	-0.3908	2.159186
2020-11-01	0.844641	5	1.336976	0.650505	-0.43035	2.119631
2020-12-01	0.544954	5	0.36463	0.650505	-0.73004	1.819945
2021-01-01	0.696429	5	0.731154	0.650505	-0.57856	1.97142
2021-02-01	1.323444	4	1.462309	0.650505	0.048454	2.598434
2021-03-01	0.705221	4	0.121859	0.650505	-0.56977	1.980212
2021-04-01	1.038762	4	1.584168	0.650505	-0.23623	2.313752
2021-05-01	1.14952	5	1.218591	0.650505	-0.12547	2.42451
2021-06-01	0.793141	4	1.34045	0.650505	-0.48185	2.068132
2021-07-01	0.861072	4	0.974873	0.650505	-0.41392	2.136062
2021-08-01	0.812444	5	0.731154	0.650505	-0.46255	2.087435
2021-09-01	0.949209	4	1.096732	0.650505	-0.32578	2.2242
2021-10-01	1.047809	5	1.34045	0.650505	-0.22718	2.322799
2021-11-01	1.008254	4	0.974873	0.650505	-0.26674	2.283245
2021-12-01	0.707039	5	1.459116	0.650505	-0.56795	1.982029
2022-01-01	0.858514	5	0.94933	0.650505	-0.41648	2.133504
2022-02-01	1.485528	4	0.94933	0.650505	0.210538	2.760519

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	0.56925	5	0.599886	0.511622	-0.43353	1.572029
2018-05-01	1.110019	4	1.079794	0.511622	0.10724	2.112799
2018-06-01	0.804138	4	0.959817	0.511622	-0.19864	1.806918
2018-07-01	0.641146	5	0.959817	0.511622	-0.36163	1.643925
2018-08-01	0.558471	4	0.719863	0.511622	-0.44431	1.561251
2018-09-01	0.788287	5	0.83984	0.511622	-0.21449	1.791066
2018-10-01	0.702944	4	0.599886	0.511622	-0.29984	1.705724
2018-11-01	0.945788	4	0.719863	0.511622	-0.05699	1.948567
2018-12-01	0.601512	6	1.319749	0.511622	-0.40127	1.604292
2019-01-01	0.735983	4	0.468029	0.511622	-0.2668	1.738763
2019-02-01	0.42766	4	0.585036	0.511622	-0.57512	1.43044
2019-03-01	0.796587	5	1.053065	0.511622	-0.20619	1.799366
2019-04-01	0.529026	4	0.585036	0.511622	-0.47375	1.531806
2019-05-01	1.070172	4	0.936058	0.511622	0.067392	2.072951
2019-06-01	0.763915	5	0.702043	0.511622	-0.23886	1.766694
2019-07-01	0.600922	4	0.702043	0.511622	-0.40186	1.603702
2019-08-01	0.518624	4	0.234014	0.511622	-0.48416	1.521403
2019-09-01	0.748439	5	0.936058	0.511622	-0.25434	1.751219
2019-10-01	0.663097	4	0.468029	0.511622	-0.33968	1.665876
2019-11-01	0.90594	4	1.170072	0.511622	-0.09684	1.90872
2019-12-01	0.561665	6	0.702043	0.511622	-0.44111	1.564444
2020-01-01	0.696136	4	1.140573	0.511622	-0.30664	1.698915
2020-02-01	0.387813	4	0.342172	0.511622	-0.61497	1.390593
2020-03-01	0.442056	5	0.456229	0.511622	-0.56072	1.444836
2020-04-01	0.03381	4	0.228115	0.511622	-0.96897	1.036589
2020-05-01	0.663426	5	0.684344	0.511622	-0.33935	1.666206
2020-06-01	0.446016	4	0.456229	0.511622	-0.55676	1.448795
2020-07-01	0.634534	4	0.570287	0.511622	-0.36825	1.637313
2020-08-01	0.546572	5	0.912459	0.511622	-0.45621	1.549352
2020-09-01	0.7711	4	0.798401	0.511622	-0.23168	1.773879
2020-10-01	0.681433	4	1.140573	0.511622	-0.32135	1.684212
2020-11-01	0.918613	5	1.026516	0.511622	-0.08417	1.921392
2020-12-01	0.568462	5	0.342172	0.511622	-0.43432	1.571241
2021-01-01	0.697058	5	0.6743	0.511622	-0.30572	1.699837
2021-02-01	0.383071	4	0.224767	0.511622	-0.61971	1.385851
2021-03-01	0.747674	4	0.786683	0.511622	-0.25511	1.750453
2021-04-01	0.475789	4	0.33715	0.511622	-0.52699	1.478568
2021-05-01	1.011271	5	1.573366	0.511622	0.008491	2.01405
2021-06-01	0.699726	4	0.786683	0.511622	-0.30305	1.702505
2021-07-01	0.532409	4	0.33715	0.511622	-0.47037	1.535189
2021-08-01	0.444447	5	0.449533	0.511622	-0.55833	1.447227
2021-09-01	0.668975	4	0.786683	0.511622	-0.3338	1.671755
2021-10-01	0.578345	5	0.561916	0.511622	-0.42443	1.581124
2021-11-01	0.815524	4	0.899066	0.511622	-0.18726	1.818304
2021-12-01	0.466337	5	0.6743	0.511622	-0.53644	1.469117
2022-01-01	0.594933	5	0.764205	0.511622	-0.40785	1.597713
2022-02-01	0.280947	4	0.327517	0.511622	-0.72183	1.283726

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	0.671782	5	0.543403	0.293066	0.097372	1.246192
2018-05-01	0.553461	4	0.77629	0.293066	-0.02095	1.127871
2018-06-01	0.623387	4	0.621032	0.293066	0.048978	1.197797
2018-07-01	0.387626	5	0.42696	0.293066	-0.18678	0.962036
2018-08-01	0.269936	4	0.310516	0.293066	-0.30447	0.844346
2018-09-01	0.449231	5	0.543403	0.293066	-0.12518	1.023641
2018-10-01	0.429739	4	0.349331	0.293066	-0.14467	1.004148
2018-11-01	0.575057	4	0.737476	0.293066	0.000648	1.149467
2018-12-01	0.354742	6	0.503829	0.293066	-0.21967	0.929152
2019-01-01	0.426831	4	0.771225	0.293066	-0.14758	1.001241
2019-02-01	0.643222	4	0.539858	0.293066	0.068813	1.217632
2019-03-01	0.518819	5	0.539858	0.293066	-0.05559	1.093228
2019-04-01	0.652653	4	0.848348	0.293066	0.078243	1.227063
2019-05-01	0.534511	4	0.578419	0.293066	-0.0399	1.108921
2019-06-01	0.604259	5	0.462735	0.293066	0.029849	1.178668
2019-07-01	0.368497	4	0.30849	0.293066	-0.20591	0.942907
2019-08-01	0.250986	4	0.192806	0.293066	-0.32342	0.825396
2019-09-01	0.430281	5	0.61698	0.293066	-0.14413	1.004691
2019-10-01	0.410789	4	0.385613	0.293066	-0.16362	0.985198
2019-11-01	0.556107	4	0.539858	0.293066	-0.0183	1.130517
2019-12-01	0.335792	6	0.462735	0.293066	-0.23862	0.910202
2020-01-01	0.407881	4	0.307037	0.293066	-0.16653	0.982291
2020-02-01	0.624272	4	0.844352	0.293066	0.049863	1.198682
2020-03-01	0.378245	5	0.460556	0.293066	-0.19616	0.952655
2020-04-01	0.419746	4	0.498935	0.293066	-0.15466	0.994156
2020-05-01	0.286958	5	0.191898	0.293066	-0.28745	0.861368
2020-06-01	0.342239	4	0.422176	0.293066	-0.23217	0.916649
2020-07-01	0.443207	4	0.690834	0.293066	-0.1312	1.017617
2020-08-01	0.329918	5	0.460556	0.293066	-0.24449	0.904327
2020-09-01	0.513613	4	0.307037	0.293066	-0.0608	1.088023
2020-10-01	0.498211	4	0.422176	0.293066	-0.0762	1.07262
2020-11-01	0.647751	5	0.690834	0.293066	0.073341	1.22216
2020-12-01	0.432325	5	0.422176	0.293066	-0.14209	1.006734
2021-01-01	0.509303	5	0.615174	0.293066	-0.06511	1.083713
2021-02-01	0.729916	4	0.730519	0.293066	0.155506	1.304325
2021-03-01	0.609602	4	0.730519	0.293066	0.035192	1.184012
2021-04-01	0.747527	4	0.768967	0.293066	0.173117	1.321936
2021-05-01	0.633606	5	0.69207	0.293066	0.059196	1.208016
2021-06-01	0.707754	4	0.92276	0.293066	0.133344	1.282163
2021-07-01	0.476082	4	0.346035	0.293066	-0.09833	1.050492
2021-08-01	0.362793	5	0.422932	0.293066	-0.21162	0.937202
2021-09-01	0.546488	4	0.69207	0.293066	-0.02792	1.120898
2021-10-01	0.531396	5	0.845864	0.293066	-0.04301	1.105806
2021-11-01	0.680936	4	0.653622	0.293066	0.106526	1.255346
2021-12-01	0.4652	5	0.768967	0.293066	-0.10921	1.03961
2022-01-01	0.542178	5	0.455628	0.293066	-0.03223	1.116588
2022-02-01	0.762791	4	0.645473	0.293066	0.188381	1.3372

Notes: All models included coefficients for the pre-COVID-19 pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Changes in substance use disorder–related inpatient hospitalizations

The substance disorder–related hospitalization rate during T0 was higher for females than males across all regions. At T0, the national substance disorder–related hospitalization rate was 2.69 (95% CI: 2.45 to 2.94) events per 100 000 persons (Table 2). During T1, the substance disorder–related hospitalization rate decreased to 1.41 (95% CI: 1.04 to 1.79) events per 100 000 persons, equating to a 50% decrease (95% CI: 39% to 66%). There was a statistically significant decrease in the national trend for substance disorder–related hospitalizations during T1 for both sexes and among females. There were no significant level changes or trends in the rates of hospitalizations with substance disorder among both males and females across all regions during T2 (Figures 3a and 3b). We observed similar results for youth aged 10 to 14 years and those aged 15 to 17 years.

Figure 3a : Descriptive text

Weekly hospitalization rate (per 100 000) with substance use disorder diagnosis of female youth (10–17 years) in Canada (except Quebec) and in British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	3.43221716	5	4.14899355	0.558981508	2.336613404	4.527820916
2018-05-01	3.667531187	4	3.478771515	0.558981508	2.57192743	4.763134943
2018-06-01	3.368330538	4	3.111745162	0.558981508	2.272726782	4.463934294
2018-07-01	2.935763207	5	3.781967197	0.558981508	1.840159451	4.031366963
2018-08-01	3.046155344	4	3.00004149	0.558981508	1.950551588	4.1417591
2018-09-01	3.177628974	5	4.005374542	0.558981508	2.082025218	4.27323273
2018-10-01	3.530504263	4	3.989416875	0.558981508	2.434900507	4.626108019
2018-11-01	3.686474847	4	4.08516288	0.558981508	2.590871091	4.782078603
2018-12-01	2.404302246	6	3.901353697	0.558981508	1.30869849	3.499906002
2019-01-01	3.423379546	4	3.474394811	0.558981508	2.32777579	4.518983302
2019-02-01	3.471288881	4	3.332903619	0.558981508	2.375685125	4.566892637
2019-03-01	3.457454439	5	4.354784446	0.558981508	2.361850683	4.553058195
2019-04-01	3.208081867	4	2.719775123	0.558981508	2.112478111	4.303685623
2019-05-01	3.445490615	4	3.06564248	0.558981508	2.349886859	4.541094371
2019-06-01	3.144195244	5	4.024638333	0.558981508	2.048591488	4.239799
2019-07-01	2.711627913	4	2.326744036	0.558981508	1.616024157	3.807231669
2019-08-01	2.824114773	4	2.861266315	0.558981508	1.728511017	3.919718529
2019-09-01	2.955588403	5	3.820262167	0.558981508	1.859984647	4.051192159
2019-10-01	3.308463692	4	3.474394811	0.558981508	2.212859935	4.404067448
2019-11-01	3.464434275	4	3.930310872	0.558981508	2.368830519	4.560038032
2019-12-01	2.182261674	6	3.218429777	0.558981508	1.086657918	3.277865431
2020-01-01	3.201338975	4	3.365783415	0.558981508	2.105735219	4.296942731
2020-02-01	3.24924831	4	3.16414662	0.558981508	2.153644554	4.344852066
2020-03-01	2.342824443	5	2.481683624	0.558981508	1.247220687	3.438428199
2020-04-01	1.886782612	4	2.093920558	0.558981508	0.791178856	2.982386368
2020-05-01	2.62145567	5	3.381293937	0.558981508	1.525851914	3.717059426
2020-06-01	2.819519331	4	2.683320418	0.558981508	1.723915575	3.915123087
2020-07-01	2.592435479	4	2.698830941	0.558981508	1.496831723	3.688039235
2020-08-01	2.728433981	5	3.458846551	0.558981508	1.632830225	3.824037737
2020-09-01	2.885513975	4	2.729851986	0.558981508	1.789910219	3.981117731
2020-10-01	3.263245199	4	2.791894077	0.558981508	2.167641443	4.358848955
2020-11-01	3.442727425	5	3.738035958	0.558981508	2.347123669	4.538331181
2020-12-01	2.18900634	5	2.480828735	0.558981508	1.093402584	3.284610096
2021-01-01	3.236535156	5	4.195609172	0.558981508	2.1409314	4.332138912
2021-02-01	3.307956133	4	3.532332722	0.558981508	2.212352377	4.40355989
2021-03-01	3.318977627	4	3.73285816	0.558981508	2.223373871	4.414581383
2021-04-01	3.094460989	4	3.516907688	0.558981508	1.998857233	4.190064745
2021-05-01	3.35538138	5	4.658360183	0.558981508	2.259777624	4.450985136
2021-06-01	3.079692373	4	3.378082384	0.558981508	1.984088617	4.175296129
2021-07-01	2.671980977	4	2.838206204	0.558981508	1.576377221	3.767584733
2021-08-01	2.807979479	5	3.470632587	0.558981508	1.712375723	3.903583235
2021-09-01	2.965059473	4	2.961606474	0.558981508	1.869455717	4.060663229
2021-10-01	3.343541127	5	4.025933801	0.558981508	2.247937371	4.439144883
2021-11-01	3.523023353	4	3.223832047	0.558981508	2.427419597	4.618627109
2021-12-01	2.268551838	5	2.851181397	0.558981508	1.172948082	3.364155595
2022-01-01	3.316080655	5	3.77970089	0.558981508	2.220476899	4.411684411
2022-02-01	3.387501632	4	3.386611997	0.558981508	2.291897876	4.483105388

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	6.850991	5	7.56515	1.961112	3.007211	10.69477
2018-05-01	6.503196	4	6.154698	1.961112	2.659416	10.34698
2018-06-01	5.865668	4	4.616024	1.961112	2.021889	9.709448
2018-07-01	4.830712	5	6.026475	1.961112	0.986933	8.674492
2018-08-01	4.786595	4	5.385361	1.961112	0.942816	8.630375
2018-09-01	4.975511	5	7.180481	1.961112	1.131731	8.81929
2018-10-01	5.779088	4	6.282921	1.961112	1.935309	9.622868
2018-11-01	7.087467	4	8.334487	1.961112	3.243688	10.93125
2018-12-01	4.053442	6	7.170704	1.961112	0.209663	7.897222
2019-01-01	6.106031	4	6.102553	1.961112	2.262252	9.949811
2019-02-01	6.08108	4	5.84828	1.961112	2.237301	9.924859
2019-03-01	6.585361	5	8.009601	1.961112	2.741581	10.42914
2019-04-01	7.070624	4	6.22969	1.961112	3.226845	10.9144
2019-05-01	6.720777	4	5.339734	1.961112	2.876997	10.56456
2019-06-01	6.085302	5	7.882465	1.961112	2.241522	9.929081
2019-07-01	5.050346	4	4.831188	1.961112	1.206567	8.894125
2019-08-01	5.004176	4	5.212598	1.961112	1.160397	8.847956
2019-09-01	5.193092	5	6.483963	1.961112	1.349312	9.036871
2019-10-01	5.996669	4	7.628192	1.961112	2.15289	9.840449
2019-11-01	7.305048	4	8.391011	1.961112	3.461269	11.14883
2019-12-01	4.271023	6	5.207429	1.961112	0.427244	8.114803
2020-01-01	6.323612	4	7.187858	1.961112	2.479833	10.16739
2020-02-01	6.298661	4	5.422419	1.961112	2.454882	10.14244
2020-03-01	4.89403	5	5.044111	1.961112	1.05025	8.737809
2020-04-01	4.715115	4	4.791905	1.961112	0.871336	8.558894
2020-05-01	5.149586	5	6.935652	1.961112	1.305807	8.993366
2020-06-01	5.296378	4	4.918008	1.961112	1.452598	9.140157
2020-07-01	4.746675	4	4.665802	1.961112	0.902896	8.590454
2020-08-01	4.768709	5	6.305138	1.961112	0.92493	8.612489
2020-09-01	5.023776	4	4.161391	1.961112	1.179996	8.867555
2020-10-01	5.884102	4	3.65698	1.961112	2.040323	9.727881
2020-11-01	7.260684	5	6.305138	1.961112	3.416905	11.10446
2020-12-01	4.300161	5	5.674724	1.961112	0.456381	8.14394
2021-01-01	6.426251	5	9.713735	1.961112	2.582472	10.27003
2021-02-01	6.469504	4	7.695297	1.961112	2.625724	10.31328
2021-03-01	7.030533	4	8.326059	1.961112	3.186753	10.87431
2021-04-01	7.572545	4	9.335278	1.961112	3.728765	11.41632
2021-05-01	7.290901	5	10.3445	1.961112	3.447122	11.13468
2021-06-01	6.721577	4	8.073754	1.961112	2.877798	10.56536
2021-07-01	5.74337	4	6.055315	1.961112	1.89959	9.587149
2021-08-01	5.765404	5	6.055315	1.961112	1.921624	9.609183
2021-09-01	6.02047	4	5.929163	1.961112	2.176691	9.86425
2021-10-01	6.890199	5	8.704516	1.961112	3.04642	10.73398
2021-11-01	8.266782	4	8.704516	1.961112	4.423002	12.11056
2021-12-01	5.296855	5	6.430111	1.961112	1.453076	9.140635
2022-01-01	7.422946	5	6.736993	1.961112	3.579166	11.26672
2022-02-01	7.466198	4	7.349447	1.961112	3.622419	11.30998

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	4.160494	5	5.255045	1.254358	1.701953	6.619035
2018-05-01	3.800227	4	3.378243	1.254358	1.341686	6.258768
2018-06-01	3.622417	4	2.377282	1.254358	1.163876	6.080958
2018-07-01	3.572651	5	4.879684	1.254358	1.11411	6.031192
2018-08-01	3.543458	4	3.378243	1.254358	1.084917	6.001999
2018-09-01	4.417614	5	5.505285	1.254358	1.959073	6.876155
2018-10-01	3.740036	4	3.878724	1.254358	1.281495	6.198577
2018-11-01	4.412743	4	5.505285	1.254358	1.954202	6.871284
2018-12-01	2.815626	6	3.990757	1.254358	0.357085	5.274167
2019-01-01	3.989694	4	4.386542	1.254358	1.531153	6.448235
2019-02-01	3.841657	4	3.899149	1.254358	1.383116	6.300198
2019-03-01	4.421533	5	6.457965	1.254358	1.962992	6.880074
2019-04-01	3.907237	4	3.289907	1.254358	1.448696	6.365778
2019-05-01	3.549337	4	2.802513	1.254358	1.090796	6.007878
2019-06-01	3.36916	5	5.848723	1.254358	0.910619	5.827701
2019-07-01	3.319394	4	1.949574	1.254358	0.860853	5.777935
2019-08-01	3.292568	4	3.7773	1.254358	0.834027	5.751109
2019-09-01	4.166724	5	5.239481	1.254358	1.708183	6.625265
2019-10-01	3.489146	4	3.289907	1.254358	1.030605	5.947687
2019-11-01	4.161853	4	4.50839	1.254358	1.703312	6.620394
2019-12-01	2.564736	6	3.896216	1.254358	0.106195	5.023277
2020-01-01	3.738804	4	3.805302	1.254358	1.280263	6.197345
2020-02-01	3.590767	4	3.448555	1.254358	1.132226	6.049308
2020-03-01	3.12546	5	2.853976	1.254358	0.666919	5.584001
2020-04-01	2.502243	4	3.210723	1.254358	0.043702	4.960784
2020-05-01	2.897804	5	3.924217	1.254358	0.439263	5.356344
2020-06-01	3.473454	4	2.972892	1.254358	1.014914	5.931995
2020-07-01	2.81267	4	3.805302	1.254358	0.354129	5.271211
2020-08-01	2.868017	5	2.735061	1.254358	0.409476	5.326558
2020-09-01	3.826713	4	3.924217	1.254358	1.368173	6.285254
2020-10-01	3.22665	4	3.448555	1.254358	0.768109	5.685191
2020-11-01	3.98153	5	4.280964	1.254358	1.522989	6.440071
2020-12-01	2.478347	5	3.091808	1.254358	0.019806	4.936888
2021-01-01	3.746349	5	4.694395	1.254358	1.287808	6.20489
2021-02-01	3.680486	4	3.051357	1.254358	1.221945	6.139027
2021-03-01	4.337875	4	4.459675	1.254358	1.879334	6.796416
2021-04-01	3.901094	4	3.755516	1.254358	1.442553	6.359635
2021-05-01	3.625367	5	5.398554	1.254358	1.166826	6.083908
2021-06-01	3.529731	4	3.638156	1.254358	1.07119	5.988272
2021-07-01	3.557479	4	3.520796	1.254358	1.098938	6.01602
2021-08-01	3.612826	5	5.046475	1.254358	1.154285	6.071367
2021-09-01	4.571523	4	4.459675	1.254358	2.112982	7.030064
2021-10-01	3.978486	5	4.811755	1.254358	1.519945	6.437027
2021-11-01	4.733366	4	3.990236	1.254358	2.274825	7.191907
2021-12-01	3.223156	5	4.218642	1.254358	0.764615	5.681697
2022-01-01	4.491159	5	5.139145	1.254358	2.032618	6.9497
2022-02-01	4.425295	4	5.139145	1.254358	1.966754	6.883836

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	3.198139	5	4.362811	0.746244	1.735501	4.660778
2018-05-01	3.360591	4	3.110523	0.746244	1.897952	4.82323
2018-06-01	3.105285	4	3.272109	0.746244	1.642647	4.567924
2018-07-01	2.72862	5	3.756865	0.746244	1.265982	4.191259
2018-08-01	2.746396	4	3.191316	0.746244	1.283757	4.209034
2018-09-01	2.794675	5	3.474091	0.746244	1.332037	4.257314
2018-10-01	3.366638	4	3.272109	0.746244	1.904	4.829277
2018-11-01	3.465159	4	3.958847	0.746244	2.00252	4.927798
2018-12-01	2.016513	6	2.865013	0.746244	0.553874	3.479152
2019-01-01	3.359342	4	3.249051	0.746244	1.896703	4.82198
2019-02-01	3.433757	4	3.168827	0.746244	1.971119	4.896396
2019-03-01	2.877909	5	3.208939	0.746244	1.41527	4.340547
2019-04-01	2.852951	4	2.125922	0.746244	1.390313	4.31559
2019-05-01	3.018629	4	2.687486	0.746244	1.55599	4.481268
2019-06-01	2.760097	5	2.847933	0.746244	1.297459	4.222736
2019-07-01	2.383432	4	2.166034	0.746244	0.920794	3.846071
2019-08-01	2.404434	4	1.885252	0.746244	0.941795	3.867072
2019-09-01	2.452713	5	3.289162	0.746244	0.990075	3.915352
2019-10-01	3.024676	4	3.048492	0.746244	1.562038	4.487315
2019-11-01	3.123197	4	3.650168	0.746244	1.660558	4.585836
2019-12-01	1.674551	6	2.966807	0.746244	0.211912	3.13719
2020-01-01	3.01738	4	3.43166	0.746244	1.554741	4.480018
2020-02-01	3.091795	4	3.391757	0.746244	1.629157	4.554434
2020-03-01	1.785174	5	1.995151	0.746244	0.322535	3.247813
2020-04-01	1.6663	4	1.835539	0.746244	0.203662	3.128939
2020-05-01	2.351522	5	3.032629	0.746244	0.888884	3.814161
2020-06-01	2.615761	4	2.51389	0.746244	1.153122	4.0784
2020-07-01	2.779246	4	2.633599	0.746244	1.316607	4.241884
2020-08-01	2.812731	5	3.790787	0.746244	1.350092	4.275369
2020-09-01	2.87672	4	2.793211	0.746244	1.414082	4.339359
2020-10-01	3.465873	4	3.232145	0.746244	2.003235	4.928512
2020-11-01	3.576878	5	4.269623	0.746244	2.114239	5.039516
2020-12-01	2.145687	5	2.275073	0.746244	0.683048	3.608326
2021-01-01	3.505971	5	4.158842	0.746244	2.043332	4.96861
2021-02-01	3.592871	4	3.559009	0.746244	2.130232	5.055509
2021-03-01	3.054212	4	3.678976	0.746244	1.591574	4.516851
2021-04-01	3.046445	4	3.239098	0.746244	1.583806	4.509084
2021-05-01	3.224606	5	4.518742	0.746244	1.761968	4.687245
2021-06-01	2.981785	4	3.51902	0.746244	1.519146	4.444423
2021-07-01	2.62231	4	2.639265	0.746244	1.159671	4.084949
2021-08-01	2.655795	5	3.119132	0.746244	1.193156	4.118433
2021-09-01	2.719784	4	2.599276	0.746244	1.257146	4.182423
2021-10-01	3.307457	5	4.438764	0.746244	1.844819	4.770096
2021-11-01	3.418462	4	2.599276	0.746244	1.955823	4.8811
2021-12-01	1.988751	5	2.59775	0.746244	0.526113	3.45139
2022-01-01	3.349035	5	4.105927	0.746244	1.886397	4.811674
2022-02-01	3.435935	4	3.434766	0.746244	1.973296	4.898574

Notes: All models included coefficients for the pre-COVID-19 pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Figure 3b : Descriptive text

Weekly hospitalization rate (per 100 000) with substance use disorder diagnosis of male youth (10–17 years) in Canada (except Quebec) and in British Columbia, Alberta and Ontario, April 2018 to March 2022

Canada

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	1.964270379	5	2.14810114	0.362414103	1.253938737	2.674602021
2018-05-01	1.876225248	4	1.77985523	0.362414103	1.165893606	2.586556891
2018-06-01	1.851445803	4	1.810542389	0.362414103	1.141114161	2.561777446
2018-07-01	1.736305645	5	1.77985523	0.362414103	1.025974003	2.446637288
2018-08-01	1.655724462	4	1.749168071	0.362414103	0.945392819	2.366056104
2018-09-01	2.011902402	5	2.593064948	0.362414103	1.301570759	2.722234044
2018-10-01	1.957667132	4	2.424285572	0.362414103	1.247335489	2.667998774
2018-11-01	2.089874579	4	2.286193356	0.362414103	1.379542937	2.800206222
2018-12-01	1.429426366	6	2.051434275	0.362414103	0.719094723	2.139758008
2019-01-01	1.951186263	4	2.255002322	0.362414103	1.240854621	2.661517906
2019-02-01	2.020162041	4	2.118794128	0.362414103	1.309830399	2.730493684
2019-03-01	1.779616758	5	2.133928371	0.362414103	1.069285116	2.489948401
2019-04-01	1.889857807	4	1.785840765	0.362414103	1.179526165	2.60018945
2019-05-01	1.802508121	4	2.058257153	0.362414103	1.092176479	2.512839764
2019-06-01	1.777033231	5	2.149062615	0.362414103	1.066701589	2.487364874
2019-07-01	1.661893073	4	1.72530379	0.362414103	0.951561431	2.372224716
2019-08-01	1.582007335	4	1.573961352	0.362414103	0.871675692	2.292338977
2019-09-01	1.938185274	5	2.587955685	0.362414103	1.227853632	2.648516917
2019-10-01	1.883950004	4	1.619364083	0.362414103	1.173618362	2.594281647
2019-11-01	2.016157452	4	1.96745169	0.362414103	1.305825809	2.726489094
2019-12-01	1.355709238	6	2.009898468	0.362414103	0.645377596	2.066040881
2020-01-01	1.877469136	4	1.837273164	0.362414103	1.167137493	2.587800778
2020-02-01	1.946444914	4	1.747650083	0.362414103	1.236113272	2.656776556
2020-03-01	1.286166478	5	1.598278281	0.362414103	0.575834836	1.996498121
2020-04-01	1.39319657	4	1.628152641	0.362414103	0.682864928	2.103528213
2020-05-01	1.66079434	5	1.822335984	0.362414103	0.950462698	2.371125983
2020-06-01	1.990962352	4	2.076268047	0.362414103	1.280630709	2.701293994
2020-07-01	1.526721071	4	1.658027002	0.362414103	0.816389429	2.237052713
2020-08-01	1.436036116	5	1.956770606	0.362414103	0.725704474	2.146367759
2020-09-01	1.782110284	4	1.598278281	0.362414103	1.071778642	2.492441927
2020-10-01	1.719589329	4	1.374220578	0.362414103	1.009257686	2.429920971
2020-11-01	1.84099756	5	2.240577029	0.362414103	1.130665917	2.551329202
2020-12-01	1.169322934	5	1.50806289	0.362414103	0.458991291	1.879654576
2021-01-01	1.679856418	5	2.049653906	0.362414103	0.969524776	2.390188061
2021-02-01	1.73803298	4	1.752602615	0.362414103	1.027701338	2.448364623
2021-03-01	1.489202012	4	1.589224405	0.362414103	0.778870369	2.199533654
2021-04-01	1.591157375	4	1.767455179	0.362414103	0.880825732	2.301489017
2021-05-01	1.493008473	5	1.960538518	0.362414103	0.78267683	2.203340115
2021-06-01	1.457429811	4	1.485256453	0.362414103	0.747098169	2.167761454
2021-07-01	1.334003968	4	1.529814147	0.362414103	0.623672325	2.04433561
2021-08-01	1.243319013	5	1.307025679	0.362414103	0.53298737	1.953650655
2021-09-01	1.589393181	4	1.529814147	0.362414103	0.879061538	2.299724823
2021-10-01	1.52505414	5	2.049653906	0.362414103	0.814722497	2.235385782
2021-11-01	1.646462371	4	1.559519276	0.362414103	0.936130728	2.356794013
2021-12-01	0.97660583	5	1.290718729	0.362414103	0.266274188	1.686937473
2022-01-01	1.487139315	5	1.645470675	0.362414103	0.776807673	2.197470958
2022-02-01	1.545315877	4	1.630908987	0.362414103	0.834984235	2.25564752

British Columbia

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	3.461968	5	3.829751	1.272708	0.967459	5.956476
2018-05-01	3.159981	4	3.45913	1.272708	0.665472	5.654489
2018-06-01	3.089585	4	3.21205	1.272708	0.595077	5.584093
2018-07-01	2.77433	5	2.717888	1.272708	0.279822	5.268838
2018-08-01	2.919123	4	4.323913	1.272708	0.424614	5.413631
2018-09-01	3.602463	5	4.447453	1.272708	1.107955	6.096971
2018-10-01	3.360476	4	4.200373	1.272708	0.865967	5.854984
2018-11-01	3.054227	4	2.594348	1.272708	0.559719	5.548735
2018-12-01	2.185187	6	2.347267	1.272708	-0.30932	4.679696
2019-01-01	3.106235	4	3.554636	1.272708	0.611727	5.600743
2019-02-01	3.576712	4	3.67721	1.272708	1.082204	6.07122
2019-03-01	2.84664	5	3.064341	1.272708	0.352132	5.341148
2019-04-01	3.903014	4	3.432062	1.272708	1.408505	6.397522
2019-05-01	3.596905	4	3.799783	1.272708	1.102396	6.091413
2019-06-01	3.530631	5	4.535225	1.272708	1.036123	6.025139
2019-07-01	3.215376	4	4.044931	1.272708	0.720868	5.709884
2019-08-01	3.356047	4	2.574047	1.272708	0.861538	5.850555
2019-09-01	4.039387	5	5.393241	1.272708	1.544879	6.533895
2019-10-01	3.7974	4	2.69662	1.272708	1.302892	6.291908
2019-11-01	3.491151	4	3.432062	1.272708	0.996643	5.985659
2019-12-01	2.622112	6	4.532134	1.272708	0.127603	5.11662
2020-01-01	3.543159	4	3.646299	1.272708	1.048651	6.037668
2020-02-01	4.013636	4	3.767843	1.272708	1.519128	6.508144
2020-03-01	2.416145	5	3.281669	1.272708	-0.07836	4.910653
2020-04-01	3.129088	4	3.281669	1.272708	0.63458	5.623596
2020-05-01	3.129048	5	4.132472	1.272708	0.63454	5.623556
2020-06-01	3.364721	4	3.160126	1.272708	0.870213	5.859229
2020-07-01	2.963202	4	2.552409	1.272708	0.468694	5.45771
2020-08-01	3.049842	5	4.010929	1.272708	0.555333	5.54435
2020-09-01	3.675029	4	4.010929	1.272708	1.180521	6.169537
2020-10-01	3.377228	4	3.281669	1.272708	0.88272	5.871737
2020-11-01	3.016949	5	4.254016	1.272708	0.52244	5.511457
2020-12-01	2.083295	5	2.795812	1.272708	-0.41121	4.577803
2021-01-01	2.939729	5	3.046477	1.272708	0.44522	5.434237
2021-02-01	3.356174	4	3.168336	1.272708	0.861666	5.850682
2021-03-01	2.570289	4	2.802759	1.272708	0.07578	5.064797
2021-04-01	3.570849	4	4.386927	1.272708	1.076341	6.065357
2021-05-01	3.210709	5	3.290195	1.272708	0.716201	5.705217
2021-06-01	3.086283	4	3.046477	1.272708	0.591775	5.580791
2021-07-01	2.715215	4	3.046477	1.272708	0.220706	5.209723
2021-08-01	2.801854	5	2.6809	1.272708	0.307346	5.296362
2021-09-01	3.427041	4	2.802759	1.272708	0.932533	5.92155
2021-10-01	3.126901	5	4.265068	1.272708	0.632393	5.621409
2021-11-01	2.766622	4	2.802759	1.272708	0.272113	5.26113
2021-12-01	1.835308	5	2.433989	1.272708	-0.6592	4.329816
2022-01-01	2.691741	5	3.44132	1.272708	0.197233	5.186249
2022-02-01	3.108186	4	3.44132	1.272708	0.613678	5.602695

Alberta

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	2.10787	5	2.879452	0.997114	0.153526	4.062214
2018-05-01	2.16899	4	2.159589	0.997114	0.214646	4.123334
2018-06-01	1.921476	4	1.919635	0.997114	-0.03287	3.875819
2018-07-01	1.886333	5	2.159589	0.997114	-0.06801	3.840676
2018-08-01	1.767417	4	1.439726	0.997114	-0.18693	3.721761
2018-09-01	2.138483	5	1.439726	0.997114	0.184139	4.092827
2018-10-01	2.158413	4	2.399543	0.997114	0.20407	4.112757
2018-11-01	2.280051	4	2.51952	0.997114	0.325707	4.234395
2018-12-01	1.673703	6	3.224534	0.997114	-0.28064	3.628047
2019-01-01	2.333164	4	3.042188	0.997114	0.37882	4.287508
2019-02-01	1.939931	4	2.457152	0.997114	-0.01441	3.894275
2019-03-01	2.293892	5	2.10613	0.997114	0.339549	4.248236
2019-04-01	2.203824	4	1.872116	0.997114	0.249481	4.158168
2019-05-01	2.264048	4	2.10613	0.997114	0.309704	4.218391
2019-06-01	2.01743	5	2.340145	0.997114	0.063086	3.971774
2019-07-01	1.982287	4	1.872116	0.997114	0.027943	3.936631
2019-08-01	1.862475	4	2.574159	0.997114	-0.09187	3.816819
2019-09-01	2.233541	5	3.744232	0.997114	0.279197	4.187884
2019-10-01	2.253471	4	1.638101	0.997114	0.299127	4.207815
2019-11-01	2.375109	4	3.042188	0.997114	0.420765	4.329453
2019-12-01	1.768761	6	2.223137	0.997114	-0.18558	3.723105
2020-01-01	2.428222	4	2.509261	0.997114	0.473878	4.382566
2020-02-01	2.034989	4	1.482745	0.997114	0.080645	3.989332
2020-03-01	1.952916	5	2.509261	0.997114	-0.00143	3.90726
2020-04-01	1.882564	4	2.167089	0.997114	-0.07178	3.836907
2020-05-01	2.342776	5	2.281147	0.997114	0.388432	4.29712
2020-06-01	2.495251	4	2.623319	0.997114	0.540908	4.449595
2020-07-01	2.090691	4	2.053032	0.997114	0.136347	4.045035
2020-08-01	1.9381	5	2.623319	0.997114	-0.01624	3.892444
2020-09-01	2.27549	4	2.395204	0.997114	0.321146	4.229834
2020-10-01	2.26459	4	2.167089	0.997114	0.310246	4.218934
2020-11-01	2.353449	5	2.623319	0.997114	0.399105	4.307793
2020-12-01	1.709684	5	1.596803	0.997114	-0.24466	3.664028
2021-01-01	2.331727	5	2.697199	0.997114	0.377384	4.286071
2021-02-01	1.905715	4	1.798133	0.997114	-0.04863	3.860059
2021-03-01	2.228846	4	2.921966	0.997114	0.274503	4.18319
2021-04-01	2.107948	4	1.910516	0.997114	0.153604	4.062291
2021-05-01	2.135392	5	3.483882	0.997114	0.181048	4.089736
2021-06-01	1.855099	4	1.910516	0.997114	-0.09924	3.809443
2021-07-01	1.789126	4	2.135283	0.997114	-0.16522	3.743469
2021-08-01	1.636535	5	1.460983	0.997114	-0.31781	3.590879
2021-09-01	1.973925	4	2.135283	0.997114	0.019581	3.928269
2021-10-01	1.96018	5	2.921966	0.997114	0.005836	3.914524
2021-11-01	2.049039	4	1.460983	0.997114	0.094695	4.003383
2021-12-01	1.408119	5	2.016477	0.997114	-0.54622	3.362463
2022-01-01	2.030162	5	1.9651	0.997114	0.075819	3.984506
2022-02-01	1.60415	4	1.746755	0.997114	-0.35019	3.558494

Ontario

Date	Predicted event rate	Number of weeks	Observed event rate (per 100 000)	Standard error of the mean	Lower 95% confidence interval	Upper 95% confidence interval
2018-04-01	1.904264	5	2.134798	0.508904	0.906812	2.901716
2018-05-01	1.763433	4	1.630209	0.508904	0.765981	2.760885
2018-06-01	1.784254	4	1.901911	0.508904	0.786802	2.781706
2018-07-01	1.580254	5	1.630209	0.508904	0.582802	2.577706
2018-08-01	1.48858	4	1.436137	0.508904	0.491128	2.486032
2018-09-01	1.742991	5	2.717016	0.508904	0.745539	2.740443
2018-10-01	1.947646	4	2.251242	0.508904	0.950194	2.945098
2018-11-01	2.154426	4	2.328871	0.508904	1.156974	3.151878
2018-12-01	1.463537	6	2.015316	0.508904	0.466085	2.460989
2019-01-01	1.993983	4	2.159431	0.508904	0.996531	2.991435
2019-02-01	2.274028	4	2.197992	0.508904	1.276576	3.27148
2019-03-01	1.589121	5	1.850941	0.508904	0.591669	2.586573
2019-04-01	1.780326	4	1.696696	0.508904	0.782874	2.777778
2019-05-01	1.640652	4	2.12087	0.508904	0.6432	2.638104
2019-06-01	1.660315	5	1.773818	0.508904	0.662863	2.657767
2019-07-01	1.456316	4	1.272522	0.508904	0.458863	2.453768
2019-08-01	1.3658	4	1.349644	0.508904	0.368348	2.363252
2019-09-01	1.62021	5	2.082308	0.508904	0.622758	2.617662
2019-10-01	1.824865	4	1.773818	0.508904	0.827413	2.822317
2019-11-01	2.031646	4	2.043747	0.508904	1.034194	3.029098
2019-12-01	1.340757	6	1.849488	0.508904	0.343305	2.338209
2020-01-01	1.871202	4	1.765464	0.508904	0.87375	2.868654
2020-02-01	2.151248	4	2.226019	0.508904	1.153796	3.1487
2020-03-01	1.112173	5	1.420047	0.508904	0.114721	2.109625
2020-04-01	1.368437	4	1.650325	0.508904	0.370985	2.365889
2020-05-01	1.614825	5	1.573565	0.508904	0.617373	2.612277
2020-06-01	2.021707	4	2.302779	0.508904	1.024255	3.019159
2020-07-01	1.514499	4	1.880602	0.508904	0.517047	2.511951
2020-08-01	1.40183	5	2.072501	0.508904	0.404378	2.399282
2020-09-01	1.635246	4	0.997871	0.508904	0.637794	2.632698
2020-10-01	1.822397	4	1.420047	0.508904	0.824945	2.819849
2020-11-01	2.007024	5	2.494677	0.508904	1.009572	3.004476
2020-12-01	1.292807	5	1.727427	0.508904	0.295355	2.290259
2021-01-01	1.799925	5	2.306901	0.508904	0.802473	2.797377
2021-02-01	2.057818	4	2.076211	0.508904	1.060366	3.05527
2021-03-01	1.355407	4	1.461037	0.508904	0.357955	2.352859
2021-04-01	1.529107	4	1.576382	0.508904	0.531655	2.52656
2021-05-01	1.367281	5	1.807072	0.508904	0.369829	2.364733
2021-06-01	1.365949	4	1.268795	0.508904	0.368496	2.363401
2021-07-01	1.144445	4	1.307244	0.508904	0.146993	2.141897
2021-08-01	1.031776	5	1.038105	0.508904	0.034324	2.029228
2021-09-01	1.265192	4	1.307244	0.508904	0.26774	2.262644
2021-10-01	1.448852	5	1.960866	0.508904	0.4514	2.446304
2021-11-01	1.633479	4	1.461037	0.508904	0.636027	2.630931
2021-12-01	0.922753	5	1.383661	0.508904	-0.0747	1.920205
2022-01-01	1.429871	5	1.670636	0.508904	0.432419	2.427323
2022-02-01	1.687764	4	1.670636	0.508904	0.690312	2.685216

Notes: All models included coefficients for the pre-COVID-19 pandemic period (102 weeks, 1 April 2018 to 14 March 2020, referred to as T0), the early pandemic period (the first 16 weeks, 15 March 2020 to 5 July 2020, referred to as T1) and the later pandemic period (89 weeks, 6 July 2020 to 5 March 2022, referred to as T2). All analyses considered autocorrelation with lag one and adjusted for seasonality by adding a covariate for each month (i.e. January to December).

All rates for Canada excluded Quebec. The population for the presented provinces represented 81% of the youth in the Canadian population (excluding Quebec). Graphs for the other Canadian jurisdictions are not shown for improved presentation.

In each graph, the dashed line is the predicted event rate, and the solid black line is the observed event rate (per 100 000). The shaded area shows the 95% confidence interval for the predicted values.

Discussion

We conducted a Canada-wide analysis to understand rate changes in mental health and addiction–related hospitalizations among youth during different phases of the COVID-19 pandemic. We found regional variations, with the territories showing the highest hospitalization rates before and during the pandemic;^{Footnote 16} this finding may be attributed to a complex interplay of factors, one of which could be limited outpatient resources in the territories, resulting in a greater reliance on inpatient hospitalizations. While there was no general increase in the mental health and addiction–related hospitalization rate, we observed a concerning rise in the self-harm–related hospitalization rate among females nationally and within most provinces.

Some Canadian studies have shown an increase in mental health–related outpatient and emergency department visits, especially among young females.^{Footnote 2Footnote 11Footnote 16Footnote 27Footnote 28Footnote 29} However, our study did not find a corresponding increase in the mental health and addiction–related inpatient hospitalization rate.^{Footnote 30} We also did not find significant changes in substance disorders, which is in line with past findings. Presentations to the emergency department for substance abuse by youth decreased during the pandemic, apart from opioid-related emergency department visits.^{Footnote 31Footnote 32} While there is evidence that there might have been an increase in the frequency of alcohol and cannabis use by youth during the pandemic, our results and past findings suggest this does not lead to an increase in visits to the hospitals and emergency departments.^{Footnote 33Footnote 34}

The rise in the rate of self-harm–related hospitalizations among female youth is alarming and calls for attention; evidence suggests it may have started before the pandemic.^{Footnote 35} This trend should guide policy makers and clinicians in allocating resources and shaping public health strategies to meet the mental health needs of this demographic. Our study also raises questions about whether the observed sex differences in hospitalization rates, particularly for self-harm and, to a lesser extent, substance disorders, could be related to systemic biases in clinical decision-making and/or gender differences in help-seeking behaviors.^{Footnote 29Footnote 36Footnote 37}

Our findings should not be interpreted to mean that mental health and addiction conditions have not increased among young people in Canada. The increase in self-reported mental health conditions and unmet needs of mental health care post-pandemic among youth continues to be corroborated by Statistics Canada and other large Canadian surveys.^{Footnote 5Footnote 38} Further, our findings may only pertain to the most severe mental health and addiction–related events, and non-hospitalized mental health and addiction events may have continued to increase. In other words, in the majority of the provinces, mental health and addiction events are not taking up inpatient hospitalizations.

Strengths and limitations

The strength of our study lies in its comprehensive coverage of included Canadian provinces and territories. However, our study also has several limitations. First, we used administrative data and diagnostic coding algorithms with high specificity but moderate to low sensitivity, potentially underestimating mental health and addiction–related hospitalization rates.^{Footnote 39} Second, the exclusion of Quebec limits the study's nationwide applicability. Third, the pandemic strained health care systems, altering hospital visit protocols and health care worker availability, which may have influenced our observed rates. Fourth, the observed trends, especially during the early pandemic period (T1), could be attributed to delayed health care–seeking behaviours for mental health and addiction–related issues due to individuals' reluctance to interact with the health care system during the pandemic, as observed in other health care contexts.^{Footnote 40Footnote 41Footnote 42} Fifth, underlying systemic biases in clinical decision-making may also affect hospital admission rates. For example, if health care providers are more inclined to admit females than males for mental health conditions, this could skew the observed sex-specific hospitalization rates.^{Footnote 10Footnote 43Footnote 44} Lastly, our findings might be influenced by unaccounted factors such as neighborhood-level socioeconomic status, racial/ethnic backgrounds and access to either the means or opportunity to self-harm or use substances.

Conclusion

While our study indicated no significant increase in overall mental health and addiction–related hospitalizations among Canadian youth during the pandemic, the rise in self-harm hospitalization rate among females warrants focused attention. These findings highlight the need for ongoing monitoring and research to better understand and address the mental health challenges faced by Canadian youth.

Acknowledgements

The authors would like to acknowledge the Canadian Institute for Health Information for collecting and providing the data used in this manuscript. The authors also thank Li Liu and Wendy Thompson for initial feedback on the proposal.

Conflicts of interest

The authors have no conflicts of interest.

Justin J. Lang is one of this journal's Associate Scientific Editors, but has recused himself from the review process for this article.

Authors' contributions and statement

• CD: Conceptualization, data curation, formal analysis, investigation, methodology, project administration, validation, visualization, writing original draft, writing review and editing
• AAA: conceptualization, data curation, formal analysis, investigation, funding acquisition, methodology, project administration, validation, visualization, supervision, writing – original draft, writing – review and editing
• EC: Conceptualization, data curation, methodology, project administration, writing – review and editing
• CO: Conceptualization, formal analysis, methodology, project administration, writing – review and editing
• NA: Conceptualization, investigation, project administration, writing – review and editing
• JJL: Conceptualization, investigation, project administration, writing – review and editing
• IC: Conceptualization, investigation, project administration, writing – review and editing
• MW: Conceptualization, project administration, writing – review and editing
• RE: Conceptualization, data curation, funding acquisition, investigation, resources, supervision, project administration, writing – review and editing

The content and views expressed in this article are those of the authors and do not necessarily reflect those of the Government of Canada.

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