Summary: A decade-long analysis of 35,000 Canadians has identified a significant and strengthening link between cannabis use and mental health challenges. The study found that as cannabis use rose between 2012 and 2022, so did the prevalence of generalized anxiety disorder, major depressive episodes, and suicidality.
Notably, the connection between these factors has grown stronger since legalization, with frequent users in 2022 being five times more likely to report mental health struggles than non-users. While the study does not prove causation, it highlights a critical public health trend, especially among youth, where suicidality increased by 44% during the study period.
Key Facts
The “Co-occurrence” Spike: The percentage of people reporting generalized anxiety disorder (5.2%) and major depressive episodes (7.6%) nearly doubled over the 10-year period.Frequent Use Growth: The number of Canadians using cannabis multiple times per week more than doubled, reaching 20.7% of the population by 2022.Youth at Risk: While suicidality remained stable in adults, it increased by 44% among youth. Younger Canadians also showed the strongest correlation between cannabis use and mental health disorders.Five-Fold Risk: By 2022, regular users (2+ times per week) were 5x more likely to experience anxiety, depression, or suicidality compared to non-users.Call for Screening: Researchers are urging mental health providers to implement routine cannabis screening and for public health officials to update “Lower Risk Cannabis Use Guidelines.”
Source: McMaster University
An analysis of 35,000 Canadians shows that rising cannabis use and worsening mental‑health symptoms are increasingly appearing together, with the connection between the two strengthening over time.
The study, led by McMaster University and published in The Canadian Journal of Psychiatry on Feb. 25, 2026, analyzed data from two large, nationally representative Statistics Canada surveys of Canadians aged 15 and older living in the provinces, to examine cannabis use and mental‑health outcomes between 2012 and 2022.
With the legalization of cannabis in Canada landing at the midpoint of the study period, the authors suggest that stronger products, wider availability and increased use for stress relief – may be contributing to the patterns they observed.
The study doesn’t prove causation, but it underscores a widening public‑health issue as cannabis use and mental‑health challenges rise in parallel.
“We see that Canadians who use cannabis tend to be more likely to meet criteria for anxiety and depressive disorders, and more likely to report suicidality. We also see that this co-occurrence has strengthened over time,” said Jillian Halladay, an assistant professor in the School of Nursing at McMaster and youth substance use research lead at the Peter Boris Centre for Addictions Research, a joint collaboration between McMaster and St. Joseph’s Healthcare Hamilton.
Key findings:
The number of people reporting generalized anxiety disorder and major depressive episode nearly doubled, increasing to 5.2 per cent and 7.6 per cent, respectively.Suicidality didn’t change much in adults but increased by 44 per cent among youth. Younger Canadians also saw some of the strongest cannabis–mental health connections.The number of people using cannabis multiple times a week more than doubled, while the number of people who reported using cannabis in the last year increased to 20.7 per cent.Canadians who used cannabis at any level, compared to those who did not, were more likely to meet criteria for generalized anxiety disorder and major depressive episode and report suicidality. The connection between cannabis use and these mental health problems strengthened over time.In 2022, Canadians who used cannabis regularly (two or more times a week) were about five times more likely to report anxiety, depression, or suicidality than those who did not use cannabis.
“This extends our prior study that similarly found a strengthening in the co-occurrence of cannabis use and these mental health problems between 2002 and 2012.”
Halladay and her fellow researchers emphasize that the growing overlap between cannabis use and mental health problems highlights the need for earlier detection of anxiety, depression, and suicidality among people who use cannabis, as well as routine screening for cannabis use in mental health settings.
The team also calls for improved prevention efforts, easier access to services that treat substance use and mental health issues together, and updates to Canada’s Lower Risk Cannabis Use Guidelines to reflect these strengthening associations.
The study highlights the need for earlier detection of anxiety, depression, and suicidality among people who use cannabis, as well as routine screening for cannabis use in mental‑health settings.
“It’s important for people to recognize when and how their cannabis use may be impacting their mental health, and how their mental health may be influencing their cannabis use. It’s also increasingly important for health and mental health providers to assess and address both cannabis use and mental health concerns together.”
This study furthers recent research from McMaster that found anxiety and depression rates among teenagers increased nearly three-fold over the last decade. In that study, rates of anxiety and depression were higher in teens who use cannabis heavily.
Funding: The research was funded through a Health Systems Impact Embedded Early Career Researcher award co‑funded by the Canadian Institutes of Health Research (CIHR), McMaster University, and St. Joseph’s Healthcare Hamilton, along with a CIHR Fellowship.
Additional support came from the Australian National Health and Medical Research Council, the Peter Boris Chair in Addictions Research, and a Canada Research Chair in Translational Addiction Research.
Key Questions Answered:Q: Does cannabis cause anxiety and depression?
A: This study shows a strong “co-occurrence,” meaning they happen together. It’s a “chicken or the egg” scenario: people may use cannabis to self-medicate for anxiety, but high-potency products might also be making those symptoms worse over time.
Q: Why is the link getting stronger now?
A: Since legalization, cannabis has become more widely available and significantly more potent. High-THC products used for stress relief may be creating a cycle where users feel temporary relief but face worsening mental health in the long run.
Q: Should I be worried about occasional use?
A: The strongest risks were found in “regular” users (twice a week or more). However, the study found that users at any level were more likely to meet criteria for depression and anxiety than non-users.
Editorial Notes:This article was edited by a Neuroscience News editor.Journal paper reviewed in full.Additional context added by our staff.About this CUD and mental health research news
Author: Adam Ward
Source: McMaster University
Contact: Adam Ward – McMaster University
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Changes in Cross-Sectional Associations Between Cannabis Use and Anxiety, Depression, and Suicidality in a Nationally Representative Sample of Canadians From 2012 to 2022” by Jillian Halladay, Chris Ji, Katholiki Georgiades, André McDonald, Matthew Sunderland, Tim Slade, Cath Chapman, and James MacKillop. Canadian Journal of Psychiatry
DOI:10.1177/07067437261420701
Abstract
Changes in Cross-Sectional Associations Between Cannabis Use and Anxiety, Depression, and Suicidality in a Nationally Representative Sample of Canadians From 2012 to 2022
Objective
As epidemiological patterns of cannabis use and internalizing problems evolve globally, it is critical to reassess their associations—particularly in the post-legalization and post-pandemic context.
Methods
Participants were assessed in the 2012 Canadian Community Health Survey’s Mental Health Component (CCHS-MH; n = 25,113) and 2022 Mental Health and Access to Care Survey (MHACS; n = 9,861), two nationally representative cross-sectional epidemiologic surveys of Canadians aged 15+.
Robust Poisson Regression analyses examined associations between frequency of cannabis use and past 12-month generalized anxiety disorder (GAD), major depressive episode (MDE), and suicidality assessed using the World Health Organization Composite International Diagnostic Interview.
Results
Between 2012 and 2022, the prevalence of GAD, MDE, and cannabis use (any and 2+/week) approximately doubled, while suicidality remained unchanged in the full sample but increased by 44% among youth. Across all models, cannabis frequency was consistently associated with a higher prevalence of GAD, MDE, and suicidality in a frequency-dependent fashion.
Additive interactions between year and cannabis on each of the outcomes demonstrated stronger associations in 2022 versus 2012. For example, from 2012 to 2022, those using cannabis 2+/week (relative to no use) had a: (1) prevalence ratio (PR) for GAD of 2.3 (95% CI, 1.6–3.4) increase to 4.5 (3.8–5.2); (2) PR for MDE of 3.0 (2.3–3.9) increase to 5.2 (4.6–5.7); and (3) PR for suicidality of 3.0 (2.1–4.0) increase to 5.4 (4.7–6.1).
Select moderation effects indicated associations between cannabis and MDE or suicidality strengthened more among youth (15–24 vs. 25+), and associations with GAD strengthened more among females.
Conclusions
Cannabis use was consistently related to a higher prevalence of internalizing problems, and these associations strengthened between 2012 and 2022. Given continued escalations in co-occurring cannabis use and internalizing problems, greater investment in early identification, intervention, and access to integrated substance use and mental health treatment is needed.