Original quantitative research – The impact of recreational cannabis legalization on pediatric emergency department visits in British Columbia, Canada
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Date published: April 2026
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Melody Xiao, BA, MScAuthor reference footnote 1; Aygun Ibrahimova, MPH, BScAuthor reference footnote 1; Atousa Zargaran, BScAuthor reference footnote 1Author reference footnote 2; Phoebe Cheng, BScAuthor reference footnote 1; Mojgan Karbakhsh, MD, MPHAuthor reference footnote 1; Fahra Rajabali, MScAuthor reference footnote 1; Kate Turcotte, MScAuthor reference footnote 1; Kirvy Quiambao, BA, MPHAuthor reference footnote 3; Shelina Babul, PhDAuthor reference footnote 1Author reference footnote 2Author reference footnote 4Author reference footnote 5
https://doi.org/10.24095/hpcdp.46.4.04
This article has been peer reviewed.
Recommended Attribution
Research article by Xiao M et al. in the HPCDP Journal licensed under a Creative Commons Attribution 4.0 International License
Author references
Correspondence
Melody Xiao, F508, 4480 Oak St., Vancouver, BC V6H 3V4; Tel: 778-319-2418; Email: Melody.Xiao@bcchr.ca
Suggested citation
Xiao M, Ibrahimova A, Zargaran A, Cheng P, Karbakhsh M, Rajabali F, Turcotte K, Quiambao K, Babul S. The impact of recreational cannabis legalization on pediatric emergency department visits in British Columbia, Canada. Health Promot Chronic Dis Prev Can. 2026;46(4):167-76. https://doi.org/10.24095/hpcdp.46.4.04
Abstract
Introduction: Canadian youth report some of the highest rates of cannabis use globally, raising concerns about child and youth poisonings from unintentional exposures and recreational use following legalization. This study examines and compares trends in cannabis poisonings among children and youth aged 16 years or younger treated in the emergency department (ED) of a Canadian pediatric hospital before and after the legalization of non-medical cannabis.
Methods: Cannabis-related ED visits at BC Children’s Hospital (BCCH) (2016–2021) were identified from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP) database using injury codes and keyword searches. Key variables included age, sex, intent, method of cannabis use, poisoning intent, season, peer use, and mode of ED arrival. Chi-square tests were used to assess associations between characteristics, and interrupted time series analysis evaluated legalization impact.
Results: There were 304 pediatric-related cannabis poisoning ED visits to BCCH between 2016 and 2021, increasing 55.5% from pre-legalization (n = 119) to post-legalization (n = 185). Unintentional poisonings rose from 4% to 12%, mainly involving the ingestion of edibles among children with a median age of 3 years. Ninety percent of cases involved intentional use, with co-consumption with other substances more common than cannabis use only. Interrupted time series analysis showed an upward trend in poisonings from 2016 to 2018, an immediate 48% increase in ED visits following legalization, followed by a decline.
Conclusion: Findings highlight the need for strengthened substance use prevention efforts, education programs, and continued surveillance to reduce harm among children and youth from intentional use and unintentional cannabis exposures, particularly involving edibles.
Keywords: child, adolescent, cannabis, edibles, poisoning, risk, legislation
Highlights
- ED visits at BC Children’s Hospital related to unintentional cannabis consumption primarily affected children with a median age of 3 years, increasing from 4% pre-cannabis legalization to 12% post-legalization.
- ED visits at BC Children’s Hospital related to poisoning from intentional cannabis use mostly involved individuals with an average age of 15 years, with co-consumption with other substances more common than cannabis-only both pre- and post-cannabis legislation.
- After legalization, youth co-consumption poisonings seen at BC Children’s Hospital ED were more common among females, and youth cannabis-only poisonings increased on weekends.
- ED visits at BC Children’s Hospital for cannabis poisoning rose from 2016 to 2018, spiked 48% at legalization, and declined in the post-cannabis legalization period.
Introduction
Canadian youth have some of the highest cannabis use rates worldwide, with 43% of youth aged 16 to 19 years reporting using cannabis at least once in the past 12 months as of 2023.Footnote 1Footnote 2 The enactment of Bill C-45 (The Cannabis Act) on 17 October 2018, legalized and regulated the production, distribution, sale and possession of cannabis in Canada.Footnote 3 While legalization was intended only for adults 18 years of age and older, it raised concern for increased intentional use as a result of increased access among adolescents and inadvertent exposure among young children, including unintentional poisonings.Footnote 4 Unintentional cases usually involve young children inadvertently ingesting cannabis products, especially edibles, whereas intentional cases are more common in adolescents and linked to recreational use, overconsumption, polysubstance use, or self-harm. Despite the high prevalence of cannabis use among Canadian youth prior to legalization, concerns remain that health risks may be escalating, as reflected by increases in emergency department (ED) visits and changes in presentation patterns.Footnote 5Footnote 6 These increases may result from increased social acceptability and shifts in perceptions, access, and consumption patterns among youth following cannabis legalization.Footnote 7Footnote 8Footnote 9
In several US states with legalized recreational cannabis, intentional exposures among youth have risen (ages 12–24 years), reflected in increased ED visits, hospitalizations and poison control calls.Footnote 10Footnote 11Footnote 12Footnote 13 In Massachusetts, over half of intentional exposure calls among adolescents aged 15 to 19 years involved polysubstance use, most often alcohol.Footnote 10 Similar patterns appear in Canada, where adolescent cannabis-related ED visits and poison control centre calls increased following legalization, with most cases involving recreational use, many involving edibles, and self-harm exposures often involving multiple substances (ages 11–18).Footnote 14Footnote 15Footnote 16Footnote 17 In the Canadian provinces of Alberta and Ontario, ED cases rose after recreational cannabis legalization, with a 20% increase in youth poisonings, particularly among adolescents aged 12 to 17 years.Footnote 14 There are also notable changes in consumption patterns among youth in British Columbia (BC). The 2023 BC Adolescent Health Survey by the McCreary Centre Society showed a shift in cannabis consumption patterns, where compared to 2018, youth aged 12 to 18 were less likely to have smoked cannabis and more likely to have consumed it in edible form during their most recent use.Footnote 16
Cannabis poses particular risks for children, who are susceptible to severe intoxication and long-term impacts on brain development.Footnote 18 US studies show rising pediatric poisonings after cannabis legalization (ages 0–12 years), mostly from young children unintentionally ingesting edibles.Footnote 19Footnote 20Footnote 21Footnote 22Footnote 23Footnote 24 Specifically in California, cannabis exposures rose sharply after legalization in 2016 and retail sales in 2018, with the largest increase in poison control calls among children under the age of 13 years and especially under the age of 6 years, driven by ingestion of cannabis gummies and candies.Footnote 25 Similar patterns have emerged in Canada, where edibles, including food and drink products infused with cannabis, were legalized in 2019.Footnote 26 Since then, unintentional pediatric exposures (ages 0–12 years), particularly from edibles, have risen, contributing to higher ED visits, hospitalizations and poison control calls across several provinces.Footnote 5Footnote 15Footnote 27Footnote 28Footnote 29 Data from the British Columbia Drug and Poison Information Centre (BC DPIC), which managed nearly 4000 cannabis-related calls between 2013 and 2021, show steady increases in calls even before legalization, with the highest rates in calls for unintentional edible exposures among children under the age of 5.Footnote 15 Another Canadian study found that among children aged 0 to 9 years, cannabis poisoning hospitalizations increased after dried cannabis flower legalization in 2018 and doubled after edibles legalization, where hospitalizations rose more in provinces permitting edibles (Ontario, Alberta, BC) compared to Quebec, a jurisdiction that prohibited edibles at that time.Footnote 30 As of 2025, all Canadian provinces and territories allow edible cannabis sales, with variations in rollout timelines; however, Quebec currently restricts products that may appeal to minors, such as sweets, chocolates and desserts, permitting only select edibles such as dried fruits and nuts.Footnote 31
There was also a notable rise in substance use among children and youth in the USA and Canada during the COVID-19 pandemic, coinciding with increased poisoning-related ED visits compared to pre-pandemic levels, with cannabis accounting for a growing proportion of poisonings. Relative increases were observed among young children (ages 6 months to 5 years) and adolescents (aged 11–18 years), with elevated proportions persisting into young adulthood (up to 24 years).Footnote 13Footnote 17Footnote 32 One US study suggested that the increase in unintentional exposures among children aged 6 months to 5 years was likely linked to more time at home and greater availability of cannabis products in households.Footnote 32 As for youth aged 11 to 24, the increased ED visits, particularly for recreational use and intentional self-harm, may be attributed to pandemic-related stressors and disruptions to routines.Footnote 13Footnote 17
Understanding the impact of legislative changes on cannabis poisonings can guide prevention policies, given young children’s susceptibility to unintentional exposures and adolescents’ risk of intentional, often polysubstance, use, which may harm their health.Footnote 33Footnote 34 A 2020 study examined cannabis poisonings in children and youth 16 years of age and younger seen at BC Children's Hospital (BCCH) before recreational cannabis legalization to establish a baseline.35 The purpose of this study is to examine trends and patterns in cannabis poisonings among children and youth under 16 years of age, seen at BCCH following the 2018 legalization of cannabis for non-medical purposes in Canada, and includes factors such as co-consumption, routes of exposure, and product types. Analyzing these changes can identify emerging risks, evaluate the effectiveness of existing safeguards like packaging and product labelling requirements, and inform development of targeted education for caregivers and communities.
Ethics approval was obtained from The University of British Columbia (UBC), Children’s and Women’s Health Centre of British Columbia (CW), Research Ethics Board; certificate number H23-00948.
Methods
Data collection and extraction
Data on cannabis poisoning-related ED visits at BCCH from 1 January 2016 to 31 December 2021 were extracted from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP) database. CHIRPP is an ED surveillance system that records injury cases, including poisonings, through the completion of forms collected at registration by patients or their caregivers. Cannabis-related poisoning cases were identified using CHIRPP codes “50NI” (poisoning or toxic effect) and “900BP” (body part not required), along with a keyword search in the injury descriptions for terms such as “cannabis,” “hash,” “CBD,” “marijuana,” “weed,” “THC,” “bong,” or “edible.” To ensure completeness, injury descriptions were reviewed to capture any missed cases.
Description of variables
Key variables extracted included age, sex, intent of cannabis consumption, intent of poisoning, patient disposition, time of cannabis use, season, method of cannabis use, peer substance use, treatment-seeking individual, and mode of ED arrival.
Cannabis use was classified as unintentional (e.g. young children inadvertently ingesting edibles) or intentional (deliberate use for psychoactive effects). The intent of poisoning was classified as intentional (including but is not exclusive to self-harm or harm by others) or unintentional. Time of poisoning was categorized by time of day—morning (12:00 a.m.–11:59 a.m.), afternoon (12:00 p.m.–5:59 p.m.), and evening (6:00 p.m.–11:59 p.m.)—and by day of the week, grouped into weekdays (Monday to Friday) and weekends (Saturday and Sunday). Seasons were defined as spring (March–May), summer (June–August), autumn (September–November), and winter (December–February). Method of cannabis use included inhalation (e.g. joint, bong, vaporizer), ingestion (e.g. brownies, gummies), or both. Peer substance use indicated whether substances were used with peers. The treatment-seeking individual was the person who brought the patient to the ED—categorized as a bystander (not involved and unrelated), family or friend, or the patient themself. Mode of ED arrival included emergency health services (e.g. ambulance or police), family, or other (e.g. self-admittance, social worker, or friend).
Data analyses
Chi-square tests were used to assess whether the distribution of cannabis-only and co-consumption poisoning cases differed across categorical variables such as sex and timing. An interrupted time series (ITS) analysis using segmented Poisson regression evaluated the immediate and long-term impact of cannabis legalization on cannabis poisoning-related ED visits. Due to the low number of monthly cases, data were aggregated quarterly, resulting in only 24 data points available for analysis. Given the small number of observations, the study was underpowered to detect modest effect, and significance was assessed at the 10% level to reduce the risk of false negatives.
The post-legalization period was defined as starting on 1 January 2019 to account for the gradual rollout and limited initial supply from licensed cannabis producers.Footnote 36 The study period was divided into pre-legalization (Q1 2016–Q4 2018) and post-legalization (Q1 2019–Q4 2021). The outcome variable was the number of cannabis poisoning cases, and the exposure variable was cannabis legalization, marked in Q1 2019. To capture the multiplicative effect of quarterly changes, the ITS model coefficient was exponentiated to produce a rate ratio. All the data analyses were conducted using R, version 4.2.3.Footnote 37
Results
During the 3-year pre-legalization period (January 2016–December 2018), there were 119 ED visits for pediatric cannabis poisoning at BCCH.Footnote 35 After legalization (January 2019–December 2021), this rose to 185 cases, representing a 55.5% increase. In both periods, over 85% of cases involved intentional cannabis use, with few resulting from unintentional consumption.
Unintentional cannabis consumption
After cannabis legalization, 12% of cannabis-related poisonings at BCCH involved unintentional consumption, compared to 4% pre-legalization.Footnote 35 In both periods, the median age was 3 years, with most cases involving the ingestion of edibles like cookies, gummies or chocolate. Most patients were treated and discharged from the ED, with few requiring admissions.
Before legalization, 80% of ED visits related to unintentional cannabis consumption involved males, with 73% on weekends.Footnote 35 After legalization, 59% involved females, with most on weekdays. In the post-legalization period, 90% of cases occurred after edibles were legalized in late 2019.
Intentional cannabis consumption
Intentional cannabis use was classified as cannabis-only or co-consumption with alcohol, illicit drugs, or medications. It accounted for 96% of cases pre-legalization and 88% post-legalization. Among 114 pre-legalization cases, 29% involved cannabis only and 71% co-consumption.Footnote 35 Post-legalization, 34% of the 163 patients used cannabis only, and 66% reported co-consumption.
The demographic comparison of intentional cannabis poisoning at BCCH before and after legalization is presented in Table 1. The median patient age was 15 years (IQR:14–16 years) for both periods. Pre-legalization, cannabis-only and co-consumption cases were evenly distributed by sex (p = 0.29).Footnote 35 Post-legalization, male cases were more likely to be cannabis-only use, while co-consumption was more common among females (p = 0.01). For co-consumption specifically, males were more likely to co-consume before legalization, while females were more likely to co-consume afterward (p < 0.01). Over 85% of cannabis poisonings were due to recreational use rather than self-harm or assault. Nearly 90% of patients were treated or observed in the ED and discharged during both periods.
| Descriptive | Substance used | |||||
|---|---|---|---|---|---|---|
| Pre-legalization January 2016–December 2018 (n = 114) |
Post-legalization January 2019–December 2021 (n = 163) |
|||||
| Cannabis co-consumption | Chi-square χ2, p, df |
Cannabis co-consumption | Chi-square χ2, p, df |
|||
| No n (%) |
Yes n (%) |
No n (%) |
Yes n (%) |
|||
| Median age in years (IQR) | 15 (14–15) | 15 (14–16) | N/A | 15 (14–15) | 15 (14–16) | N/A |
| Sex | ||||||
| Male | 16 (49%) | 48 (59%) | χ2 = 1.11, p = 0.29, df = 1 | 33 (60%) | 39 (36%) | χ2 = 7.49, p = 0.01, df = 1 |
| Female | 17 (52%) | 33 (41%) | χ2 = 1.11, p = 0.29, df = 1 | 22 (40%) | 69 (64%) | χ2 = 7.49, p = 0.01, df = 1 |
| Intent of poisoning | ||||||
| Unintentional | 45 (98%) | 59 (87%) | Footnote b | 53 (96%) | 87 (81%) | Footnote b |
| Intentional self-harm | Footnote a | 6 (9%) | Footnote b | Footnote a | 12 (11%) | Footnote b |
| Other intents | Footnote a | Footnote a | Footnote b | Footnote a | 8 (7%) | Footnote b |
| Patient disposition | ||||||
| No treatment (advice only, diagnostic testing, referred to GP) | 7 (21%) | 19 (24%) | Footnote b | 16 (29%) | 21 (19%) | Footnote b |
| Treated, follow-up may or may not be required | 7 (21%) | 27 (33%) | Footnote b | 17 (36%) | 35 (32%) | Footnote b |
| Observation, follow-up may or may not be required | 16 (49%) | 26 (32%) | Footnote b | 12 (22%) | 31 (29%) | Footnote b |
| Admittance into hospital for treatment | Footnote a | 8 (10%) | Footnote b | 5 (11%) | 13 (12%) | Footnote b |
| Other treatments | Footnote a | Footnote a | Footnote b | Footnote a | 8 (7%) | Footnote b |
During the pre-legalization period, cannabis-only and co-consumption poisoning differed significantly in timing (Table 2).Footnote 35 Nearly half of cannabis-only cases occurred in the afternoon, with the rest occurring in the evening (p < 0.01).Footnote 35 Co-consumption cases occurred mostly in the evening (58%), followed by morning (24%) and afternoon (16%) (p = 0.01).Footnote 35 Post-legalization, time of day was unknown for 33% of cannabis-only cases and 58% of co-consumption cases. Poisonings were more common on weekdays pre-legalization (p = 0.01)Footnote 35 with a rise in weekend cannabis-only poisonings observed post-legalization. Seasonality was associated with poisoning type pre-legalization (p = 0.05), with fewer cannabis-only cases in spring (15%) and fewer co-consumption cases in winter (12%).Footnote 35 No seasonal association was found post-legalization.
| Descriptive | Substance used | |||||
|---|---|---|---|---|---|---|
| Pre-legalization January 2016–December 2018 (n = 114) |
Post-legalization January 2019–December 2021 (n = 163) |
|||||
| Cannabis co-consumption | Chi-square χ2, p, df |
Cannabis co-consumption | Chi-square χ2, p, df |
|||
| No n (%) |
Yes n (%) |
No n (%) |
Yes n (%) |
|||
| Time of the day | ||||||
| Morning | Note de bas de page a | 19 (24%) | χ2 = 11.86, p < 0.01, df = 2Note de bas de page d | 7 (13%) | 12 (11%) | Note de bas de page b |
| Afternoon | 15 (46%) | 13 (16%) | χ2 = 11.86, p < 0.01, df = 2Note de bas de page d | 18 (33%) | 17 (16%) | Note de bas de page b |
| Evening | 14 (42%) | 47 (58%) | χ2 = 11.86, p < 0.01, df = 2Note de bas de page d | 12 (22%) | 16 (15%) | Note de bas de page b |
| Unknown | Note de bas de page a | Note de bas de page a | χ2 = 11.86, p < 0.01, df = 2Note de bas de page d | 18 (33%) | 63 (58%) | Note de bas de page b |
| Time of the week | ||||||
| Weekday | 30 (91%) | 56 (69%) | χ2 = 6.00, p = 0.01, df = 1Note de bas de page d | 39 (71%) | 70 (65%) | χ2 = 0.37, p = 0.54, df = 1 |
| Weekend | Note de bas de page a | 25 (31%) | χ2 = 6.00, p = 0.01, df = 1Note de bas de page d | 16 (29%) | 38 (35%) | χ2 = 0.37, p = 0.54, df = 1 |
| Season | ||||||
| Spring | 5 (15%) | 23 (28%) | χ2 = 7.76, p = 0.05, df = 3 | 9 (16%) | 17 (16%) | χ2 = 5.39, p = 0.15, df = 3 |
| Summer | 10 (30%) | 18 (22%) | χ2 = 7.76, p = 0.05, df = 3 | 20 (36%) | 26 (24%) | χ2 = 5.39, p = 0.15, df = 3 |
| Autumn | 8 (24%) | 30 (37%) | χ2 = 7.76, p = 0.05, df = 3 | 18 (33%) | 33 (31%) | χ2 = 5.39, p = 0.15, df = 3 |
| Winter | 10 (30%) | 10 (12%) | χ2 = 7.76, p = 0.05, df = 3 | 8 (15%) | 32 (30%) | χ2 = 5.39, p = 0.15, df = 3 |
| Year | ||||||
| 2016 | 8 (24%) | 27 (33%) | χ2 = 1.2, p = 0.55, df = 2 | Note de bas de page c | Note de bas de page c | Note de bas de page c |
| 2017 | 10 (30%) | 25 (31%) | χ2 = 1.2, p = 0.55, df = 2 | Note de bas de page c | Note de bas de page c | Note de bas de page c |
| 2018 | 15 (46%) | 29 (36%) | χ2 = 1.2, p = 0.55, df = 2 | Note de bas de page c | Note de bas de page c | Note de bas de page c |
| 2019 | Note de bas de page c | Note de bas de page c | Note de bas de page c | 23 (42%) | 49 (45%) | χ2 = 2.11, p = 0.35, df = 2 |
| 2020 | Note de bas de page c | Note de bas de page c | Note de bas de page c | 20 (36%) | 28 (26%) | χ2 = 2.11, p = 0.35, df = 2 |
| 2021 | Note de bas de page c | Note de bas de page c | Note de bas de page c | 12 (22%) | 31 (29%) | χ2 = 2.11, p = 0.35, df = 2 |
Inhalation alone was the most common method of cannabis consumption for both cannabis-only and co-consumption poisonings (Table 3). Over half of cannabis poisoning cases involved peer substance use for both cannabis-only and co-consumption for both periods. Pre-legalization, individuals who used only cannabis were most often brought in by family members, and those who co-consumed cannabis with other substances were more often brought in by both bystanders and family (p = 0.01). Post-legalization, family continued to be the main group helping individuals access treatment, for both cannabis-only use and co-use with alcohol. Emergency health services (EHS), including police and ambulance (ground or air), accounted for most ED arrivals for both cannabis-only and co-consumption poisonings during both the pre- and post-legalization periods.
| Descriptive | Substance used | |||||
|---|---|---|---|---|---|---|
| Pre-legalization January 2016–December 2018 (n = 114) |
Post-legalization January 2019–December 2021 (n = 163) |
|||||
| Cannabis co-consumption | Chi-square χ2, p, df |
Cannabis co-consumption | Chi-square χ2, p, df |
|||
| No n (%) |
Yes n (%) |
No n (%) |
Yes n (%) |
|||
| Method of cannabis use | ||||||
| Inhalation | 20 (67%) | 59 (81%) | Footnote b | 27 (53%) | 56 (55%) | Footnote b |
| Ingestion | 10 (33%) | Footnote a | Footnote b | 14 (27%) | 14 (14%) | Footnote b |
| Multiple | Footnote a | Footnote a | Footnote b | Footnote a | Footnote a | Footnote b |
| Unknown | Footnote a | 10 (14%) | Footnote b | 6 (12%) | 30 (29%) | Footnote b |
| Peer substance use | ||||||
| No | 11 (33%) | 13 (16%) | χ2 = 2.93, p = 0.09, df = 1 | 8 (15%) | 9 (8%) | Footnote c |
| Yes | 18 (55%) | 49 (61%) | χ2 = 2.93, p = 0.09, df = 1 | 18 (33%) | 58 (54%) | Footnote c |
| Unknown | Footnote a | 19 (24%) | χ2 = 2.93, p = 0.09, df = 1 | 29 (53%) | 41 (38%) | Footnote c |
| Treatment-seeking individual | ||||||
| Bystander | Footnote a | 32 (40%) | χ2 = 9.14, p = 0.01, df = 2Note de bas de page d | 13 (24%) | 28 (26%) | Footnote c |
| Patient | 8 (24%) | 9 (11%) | χ2 = 9.14, p = 0.01, df = 2Note de bas de page d | 5 (9%) | 10 (9%) | Footnote c |
| Family | 15 (45%) | 28 (35%) | χ2 = 9.14, p = 0.01, df = 2Note de bas de page d | 16 (29%) | 43 (40%) | Footnote c |
| Unknown | 6 (18%) | 9 (15%) | χ2 = 9.14, p = 0.01, df = 2Note de bas de page d | 21 (38%) | 27 (25%) | Footnote c |
| Mode of ED arrival | ||||||
| EHS | 23 (70%) | 72 (89%) | Footnote b | 28 (51%) | 82 (76%) | Footnote b |
| Family | 7 (21%) | 5 (6%) | Footnote b | 9 (16%) | 10 (9%) | Footnote b |
| Other(s) | Footnote a | Footnote a | Footnote b | Footnote a | Footnote a | Footnote b |
| Unknown | Footnote a | Footnote a | Footnote b | 17 (31%) | 15 (14%) | Footnote b |
Impact of cannabis legalization
The observed and predicted trends in child cannabis poisoning cases are shown in Figure 1, highlighting the impact of the cannabis legislation, with the interrupted time series results provided in Table 4. From 2016 to 2021, there was a non-significant average increase per quarter of 4.6% in the number of BCCH ED cannabis poisoning cases. Cannabis legalization was associated with an immediate increase of 47.9% (90% confidence interval [CI]: 3.0%–113.1%) in cannabis poisoning cases. This increase was statistically significant at the 10% level (p = 0.076). Since the 2019 legalization, cannabis poisoning cases have declined by 7.1% per quarter (90% CI: −12.3%, −1.8%, p = 0.030), a decrease that is statistically significant at the 5% level.
Figure 1: Descriptive text
| Time period | Actual number of cannabis poisoning cases | Predicted number of cannabis poisoning cases |
|---|---|---|
| 2016 Q1 | 4 | 7.6 |
| 2016 Q2 | 6 | 8.0 |
| 2016 Q3 | 12 | 8.4 |
| 2016 Q4 | 14 | 8.8 |
| 2017 Q1 | 11 | 9.2 |
| 2017 Q2 | 4 | 9.6 |
| 2017 Q3 | 11 | 10.0 |
| 2017 Q4 | 10 | 10.5 |
| 2018 Q1 | 10 | 11.0 |
| 2018 Q2 | 15 | 11.5 |
| 2018 Q3 | 11 | 12.0 |
| 2018 Q4 | 11 | 12.5 |
| 2019 Q1 | 17 | 18.0 |
| 2019 Q2 | 13 | 17.5 |
| 2019 Q3 | 22 | 17.0 |
| 2019 Q4 | 22 | 16.5 |
| 2020 Q1 | 11 | 16.0 |
| 2020 Q2 | 14 | 15.6 |
| 2020 Q3 | 16 | 15.1 |
| 2020 Q4 | 16 | 14.7 |
| 2021 Q1 | 11 | 14.3 |
| 2021 Q2 | 21 | 13.8 |
| 2021 Q3 | 11 | 13.4 |
| 2021 Q4 | 11 | 13.1 |
Abbreviation: CHIRPP, Canadian Hospitals Injury Reporting and Prevention Program.
Note: The red dotted line represents the timing of cannabis legalization as defined in this study.
| Predictor | % change (from rate ratio) | 90% confidence interval | p value |
|---|---|---|---|
| Pre-legalization trend | 4.6% | 0.1%, 9.3% | 0.093Footnote * |
| Change at time of legalization | 47.9% | 3.0%, 113.1% | 0.076Footnote * |
| Trend since legalization | −7.1% | −12.3%, −1.8% | 0.030Footnote * |
Discussion
Our study showed that cannabis-related ED visits at BCCH rose yearly from 2016 to 2018, with an immediate 48% increase at legalization, after which the rate of increase declined. Data from the McCreary Centre Society showed that self-reported cannabis uses among youth aged 12 to 19 years fell from 25% in 2018 to 22% in 2023.Footnote 16 BC DPIC reported that although cannabis poisoning calls rose from 2013 through 2021, cannabis legalization did not have an immediate effect on the rate of cannabis poisoning cases, and that the rate of increase slowed post-legalization.Footnote 15
Building on these trends, unintentional cannabis poisonings remain a concern, particularly regarding young children. Our findings showed that during the post-legalization period, 90% of inadvertent cannabis consumption by young children occurred after the legalization of edibles in late 2019. This pattern extended beyond BC, as hospitalization data from Ontario and Alberta show a rise in unintentional cannabis poisonings among children aged 0 to 9 years with the increase in the commercial sale of cannabis edibles in 2019.Footnote 30 BC DPIC reported that children under the age of 5 years consistently had the highest rates of unintentional cannabis edible exposures from 2013 to 2021. While poison centre calls involving edibles continued to rise after legalization, the pace of increase was slower than during the pre-legalization period.Footnote 15 Despite this difference from our ED findings, the continued rise in pediatric exposures points to greater household availability of cannabis edibles post-legalization, increasing the risk of unintentional ingestion. Canada’s Cannabis Act requires all cannabis products to be sold in plain packaging and child-resistant containers, restricts promotions that could appeal to youth, mandates Health Warning Messages on packaging as well as display of the standardized cannabis symbol, and limits edible cannabis to a maximum of 10 mg THC per package to reduce the risk of unintentional overconsumption.Footnote 38 Nevertheless, overconsumption may still occur if multiple packages are opened and stored together, illicit products are used or if products are made at home. These findings highlight the need for stronger poisoning prevention strategies, including public education on safe storage and awareness to help families distinguish legal from illegal products, as well as continued efforts to shift consumers toward the legal market.
Nearly 90% of pediatric cannabis-related ED visits in BC involved intentional use, mainly among youth with an average age of 15 years, with inhalation being the most common mode of consumption both before and after legalization. This ongoing predominance likely reflects, in part, the legalization of inhaled cannabis extracts in late 2019. Age-based differentiation in routes of exposure aligns with previous research—that ingestion is more common in children under 10 years of age while inhalation tends to be more prevalent among older youth, highlighting age-specific differences in access and modes of consumption.Footnote 10Footnote 11Footnote 21 In Canada, intentional cannabis use among youth is frequently associated with the co-consumption of other substances, particularly alcohol.Footnote 35 This pattern is not unique to Canada, as European surveys of youth aged 15 to 20 years report most adolescent cannabis use occurs with alcohol, and US surveys indicate that about 20% of Grade 12 students use alcohol and cannabis simultaneously.Footnote 39Footnote 40 Teens who co-consume alcohol and cannabis tend to exhibit more problematic behavioural and substance use profiles; they smoke and drink more, and are more likely to experience social and behavioural challenges.Footnote 41
Sex-based patterns in intentional consumption shifted after legalization. Before legalization, cannabis-only and co-consumption poisonings were similarly distributed between males and females. Post-legalization, females were more likely to present with co-consumption and accounted for a larger proportion of ED admissions. This may reflect the overlap with the COVID-19 pandemic, during which some evidence suggests that adolescent girls were more likely to use cannabis as a coping mechanism.Footnote 13 Another possible factor is the increased social acceptability of cannabis following legalization, which may have particularly influenced female youth.Footnote 42 The narrowing gender gap in cannabis use appears to be shaped by changing social and gender norms, as well as increased accessibility and normalization.
According to the McCreary Centre Society, youth most often cite experimentation, fun and peer influence as reasons for cannabis use, though some report using it to manage stress or pain.Footnote 16 Strengthening family communication and school connectedness may help reduce risks, as a 2022 study found both factors had a direct protective effect against recent cannabis use among middle and high school students.Footnote 43 School connectedness includes feeling cared for and participating in school activities; and supportive family practices include regular family meals, family routines, and strong parent-child relationships.Footnote 44 A meta-analysis of youth cannabis prevention programs found that school-based prevention programs combining drug education with emotional and behavioural skill-building are more effective than those relying only on social influence (e.g. resisting peer pressure).Footnote 45 School-based programs that last longer tend to be more effective at reducing cannabis use among youth. These programs produce stronger outcomes by making students less likely to start or more likely to reduce cannabis use, as longer duration allows more opportunities to reinforce prevention messages.Footnote 45
Beyond school-based programs, strong regulations play a critical role in preventing youth cannabis use. In Canada and the USA, similar strict age limits apply, legalizing cannabis use for adults aged 18 years and older. Licensed retailers must verify the customer’s age for all purchases, often using scanners, making it difficult for underage individuals to purchase cannabis.Footnote 46 For online purchases, customers are required to confirm their age at the point of sale, and upon delivery, couriers must verify the recipient’s age by checking government-issued identification to ensure compliance with legal requirements.Footnote 47 Additionally, regulations limit the proximity of cannabis stores to sensitive areas; for instance, Ontario requires a minimum distance of 150 metres from schools, Alberta mandates 100 metres, and Edmonton has extended buffers to 200 metres from schools, parks and libraries.Footnote 48 Because of these strict regulations, youth face barriers to accessing cannabis through legal channels and often turn to illegal markets, where no such restrictions exist.Footnote 49 The McCreary Centre Society survey found that 10% of youth aged 12 to 18 years reported buying cannabis from a store, and 3% had bought it online.Footnote 16 While the survey did not specify whether it was from the illegal market, the findings highlight the ongoing need to strengthen efforts to limit youth access to cannabis.
Strengths and limitations
Few studies have examined the impact of cannabis legalization in BC. This paper builds upon our prior work, which analyzed the landscape of pediatric cannabis poisonings at BCCH before legalization.Footnote 35 By continuing surveillance and analyzing patient records following legalization, this study examines post-legalization records to show how policy changes affected pediatric cannabis-related ED visits.
The study period includes the COVID-19 pandemic, during which data collection practices were adapted to minimize virus transmission. To reduce contact, CHIRPP forms were not distributed to patients; incident details were abstracted from medical charts; staff contact with patients was limited, and discharges were expedited due to COVID-19 policies that restricted in-person interactions to reduce the risk of infection. Because of the overlap with the COVID-19 pandemic, it is not possible to disentangle the effects of cannabis legalization from pandemic-related shifts in health care use and youth-substance-use patterns. Although Canadian data showed a decline in youth substance-related ED visits during the early pandemic period, this may be attributed to changes in care-seeking behaviour, particularly if poisoning cases were milder and less likely to visit hospital.Footnote 50 Therefore, ED visit data may be undercounted. Another limitation pertains to the ascertainment of intent, as limited interaction with patients during the pandemic made it more difficult to assess whether the poisoning was intentional or unintentional. Ongoing surveillance of pediatric ED visits in the post-legalization and post-pandemic periods is essential for tracking trends and patterns in cannabis-related harms. This will allow the public to evaluate the effectiveness of current regulations, and inform timely, evidence-based policy and prevention strategies.
Conclusion
The number of pediatric-related cannabis ED visits seen at BCCH rose from 119 pre-legalization to 185 post-legalization; however, while visits were rising, the rate of increase declined following legalization. Most cannabis poisonings involved intentional inhalation, with a median age of 15 years, across both pre- and post-legalization periods. After legalization, females were more likely to present with co-consumption and accounted for a larger proportion of ED visits. This study highlights the characteristics of unintentional and intentional cannabis exposures among children and youth. These findings underscore the importance of ongoing surveillance, including the need to create positive social environments, promote school-based education programs, and increased enforcement to reduce youth access and minimize harm among children and youth. The post-legalization shifts in sex-based patterns, including rises in co-consumption among adolescent females, point to the need for gender-sensitive substance use prevention strategies. In addition, the rise in unintentional edible exposures among young children reinforces the need for strengthened poisoning prevention efforts, particularly targeting cannabis edibles.
Acknowledgements
The authors would like to thank the Public Health Agency of Canada, the BCCH CHIRPP team members for data collection, and the BC Injury Research and Prevention Unit for their support and guidance.
Conflicts of interest
The authors declare that they have no conflicts of interest.
Authors’ contributions and statement
AZ, SB, PC conceptualized the plan and objectives for this study. AZ led the data collection. MX conducted the analyses and interpretation of the results, and drafted the manuscript. AI conducted the literature review, drafted the manuscript and contributed to interpreting results. FR, KQ, MK helped with the analysis and interpretation of the results. KT provided support with the ethics application and interpretation. All authors contributed to the review and revision of the manuscript. All authors read and approved the final manuscript.
The content and views expressed in this article are those of the authors and do not necessarily reflect those of the Government of Canada.