Depression in adolescence predicted later weekly cannabis use, but cannabis-suicidal ideation link was explained by other substance use
In a longitudinal study of 1,606 adolescents, depression at age 15 predicted weekly cannabis use at 17, while the apparent link between cannabis and suicidal ideation was fully explained by concurrent alcohol, tobacco, and other drug use.
Quick Facts
What This Study Found
Depression at age 15 predicted weekly cannabis use at age 17 (OR = 2.30, 95% CI: 1.19-4.43), even after adjusting for other substance use. Weekly cannabis use at 15 was initially associated with suicidal ideation at 17 (OR = 2.19, 95% CI: 1.04-4.58), but this association disappeared after controlling for other substance use.
Key Numbers
Weekly cannabis use: 7.0% at age 15, rising to 15.6% by age 20. Weekly users were 11-15 times more likely to continue using over time. Depression predicting cannabis: OR = 2.30. Cannabis-suicidal ideation link (before adjustment): OR = 2.19.
How They Did This
Population-based cohort of 1,606 adolescents from Quebec followed from 1997, with cross-lagged analyses examining the direction of associations between cannabis use frequency, depressive symptoms, and suicidal ideation at ages 15, 17, and 20.
Why This Research Matters
This study helps untangle the direction of the cannabis-depression relationship, suggesting depression may drive cannabis use rather than the reverse, and that polysubstance use complicates simple causal narratives.
The Bigger Picture
The finding that depression precedes cannabis use rather than the reverse challenges assumptions that cannabis causes depression. Meanwhile, the polysubstance context of suicidal ideation risk underscores that cannabis rarely operates in isolation.
What This Study Doesn't Tell Us
Quantity of cannabis consumed was not measured; self-reported data; Quebec-specific population may limit generalizability; observational design cannot fully establish causation.
Questions This Raises
- ?Are depressed adolescents using cannabis as self-medication?
- ?Would earlier treatment of depression reduce subsequent cannabis use?
Trust & Context
- Key Stat:
- Depressed 15-year-olds were 2.3x more likely to use cannabis weekly by age 17
- Evidence Grade:
- Large population-based longitudinal cohort with cross-lagged analysis, though observational design limits causal inference.
- Study Age:
- Published in 2020.
- Original Title:
- Cannabis use, depression and suicidal ideation in adolescence: direction of associations in a population based cohort.
- Published In:
- Journal of affective disorders, 274, 1076-1083 (2020)
- Authors:
- Bolanis, Despina, Orri, Massimiliano(2), Castellanos-Ryan, Natalie(7), Renaud, Johanne, Montreuil, Tina, Boivin, Michel, Vitaro, Frank, Tremblay, Richard E, Turecki, Gustavo, Côté, Sylvana M, Séguin, Jean R, Geoffroy, Marie-Claude
- Database ID:
- RTHC-02433
Evidence Hierarchy
Follows a group of people over time to track how outcomes develop.
What do these levels mean? →Frequently Asked Questions
Does this study show cannabis causes depression?
The opposite direction was supported: depression at earlier time points predicted later cannabis use, not the other way around. The findings suggest depressed adolescents may be more likely to start using cannabis regularly.
Does weekly cannabis use increase suicide risk?
An initial association was found, but it disappeared after accounting for concurrent alcohol, tobacco, and other drug use. The suicidal ideation risk appears tied to polysubstance use patterns rather than cannabis specifically.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02433APA
Bolanis, Despina; Orri, Massimiliano; Castellanos-Ryan, Natalie; Renaud, Johanne; Montreuil, Tina; Boivin, Michel; Vitaro, Frank; Tremblay, Richard E; Turecki, Gustavo; Côté, Sylvana M; Séguin, Jean R; Geoffroy, Marie-Claude. (2020). Cannabis use, depression and suicidal ideation in adolescence: direction of associations in a population based cohort.. Journal of affective disorders, 274, 1076-1083. https://doi.org/10.1016/j.jad.2020.05.136
MLA
Bolanis, Despina, et al. "Cannabis use, depression and suicidal ideation in adolescence: direction of associations in a population based cohort.." Journal of affective disorders, 2020. https://doi.org/10.1016/j.jad.2020.05.136
RethinkTHC
RethinkTHC Research Database. "Cannabis use, depression and suicidal ideation in adolescenc..." RTHC-02433. Retrieved from https://rethinkthc.com/research/bolanis-2020-cannabis-use-depression-and
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.