Depression predicted worse cannabis cessation outcomes, especially in women
In a clinical trial for cannabis use disorder, higher baseline depression predicted less cannabis abstinence during treatment, and depressive symptoms preceded increased cannabis use in the following month.
Quick Facts
What This Study Found
N-acetylcysteine did not reduce depressive symptoms compared to placebo. Higher baseline depression was associated with decreased abstinence throughout treatment, with a significant gender interaction suggesting this was particularly true for women. Cross-lagged models showed depressive symptoms preceded increased cannabis use, but not the reverse.
Key Numbers
302 adults with cannabis use disorder. 12-week trial. NAC did not differ from placebo on depression. Higher baseline depression predicted decreased abstinence. Gender interaction was significant, with stronger effects in females.
How They Did This
Secondary analysis of a multi-site RCT (N=302) comparing 2,400 mg/day NAC vs placebo for cannabis use disorder over 12 weeks. All participants received contingency management. Depression measured by HADS. Cannabis use verified by urinary cannabinoid levels.
Why This Research Matters
The directional finding (depression leads to more cannabis use, but not vice versa) suggests treating depression could improve cannabis cessation outcomes, and that women may need particular attention in this regard.
The Bigger Picture
This study challenges the self-medication hypothesis in both directions: cannabis use did not appear to worsen depression, but depression did drive increased cannabis use, particularly in women.
What This Study Doesn't Tell Us
Secondary analysis, so the study was not originally designed or powered to test these depression-related questions. Depression was measured with a screening tool (HADS), not a diagnostic interview. Predominantly male sample limits gender-related conclusions.
Questions This Raises
- ?Would directly treating depression alongside cannabis use disorder improve cessation outcomes?
- ?Why might the depression-cannabis link be stronger in women?
- ?Would different antidepressant approaches combined with CUD treatment be more effective?
Trust & Context
- Key Stat:
- Depressive symptoms preceded increased cannabis use, not the reverse
- Evidence Grade:
- Secondary analysis from a well-designed multi-site RCT with objective cannabis measures, though not originally designed for these questions.
- Study Age:
- 2020 publication from a NIDA Clinical Trials Network study. Contributes to understanding the temporal relationship between depression and cannabis use.
- Original Title:
- Depressive symptoms and cannabis use in a placebo-controlled trial of N-Acetylcysteine for adult cannabis use disorder.
- Published In:
- Psychopharmacology, 237(2), 479-490 (2020)
- Authors:
- Tomko, Rachel L(11), Baker, Nathaniel L(12), Hood, Caitlyn O, Gilmore, Amanda K, McClure, Erin A, Squeglia, Lindsay M, McRae-Clark, Aimee L, Sonne, Susan C, Gray, Kevin M
- Database ID:
- RTHC-02883
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Did NAC help with depression in cannabis users?
No. Depressive symptoms did not differ between the NAC and placebo groups during the 12-week trial.
Does cannabis use cause depression?
In this study, the data did not support that direction. Instead, depressive symptoms preceded increased cannabis use in the following month, suggesting depression may drive use rather than the other way around.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02883APA
Tomko, Rachel L; Baker, Nathaniel L; Hood, Caitlyn O; Gilmore, Amanda K; McClure, Erin A; Squeglia, Lindsay M; McRae-Clark, Aimee L; Sonne, Susan C; Gray, Kevin M. (2020). Depressive symptoms and cannabis use in a placebo-controlled trial of N-Acetylcysteine for adult cannabis use disorder.. Psychopharmacology, 237(2), 479-490. https://doi.org/10.1007/s00213-019-05384-z
MLA
Tomko, Rachel L, et al. "Depressive symptoms and cannabis use in a placebo-controlled trial of N-Acetylcysteine for adult cannabis use disorder.." Psychopharmacology, 2020. https://doi.org/10.1007/s00213-019-05384-z
RethinkTHC
RethinkTHC Research Database. "Depressive symptoms and cannabis use in a placebo-controlled..." RTHC-02883. Retrieved from https://rethinkthc.com/research/tomko-2020-depressive-symptoms-and-cannabis
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.