Antidepressant vortioxetine improved clinician-rated mood in cannabis users but did not reduce cannabis use
In a small pilot RCT, cannabis users taking vortioxetine showed improved clinician-observed mood over 6 months, but the antidepressant did not reduce cannabis dependence, self-reported symptoms, or cognitive outcomes.
Quick Facts
What This Study Found
Vortioxetine (10mg/day) improved clinician-observed mood (p<.05) but not self-reported anxiety or depression; no improvement in cannabis dependence, cognition, or functional outcomes; standard treatment group showed no improvement.
Key Numbers
11 vortioxetine (mean 10 mg/day) vs 19 standard treatment; significant clinician-rated mood improvement (p<.05); no significant between-group differences on cannabis dependence, cognition, or function.
How They Did This
6-month prospective RCT; 30 cannabis users with anxiety/depressive symptoms randomized to vortioxetine (n=11) or standard treatment (n=19).
Why This Research Matters
There are no approved medications for cannabis use disorder, and this pilot suggests vortioxetine may help with comorbid mood symptoms even if it does not address cannabis use directly.
The Bigger Picture
Treating comorbid mood symptoms in cannabis users may improve engagement with treatment even if cannabis use itself does not change.
What This Study Doesn't Tell Us
Very small sample; unequal group sizes; no placebo control; clinician-rated improvement may reflect observer bias; 6-month follow-up may be insufficient.
Questions This Raises
- ?Would a larger placebo-controlled trial confirm the mood benefit?
- ?Could mood improvement eventually lead to cannabis reduction?
- ?Is the disconnect between clinician and self-report meaningful?
Trust & Context
- Key Stat:
- Clinician-rated mood improved (p<.05) but self-reported symptoms and cannabis use did not change
- Evidence Grade:
- Randomized design but very small sample, unequal groups, and lack of placebo limit conclusions.
- Study Age:
- Published 2025
- Original Title:
- Vortioxetine improves illness severity for cannabis users with anxiety and depressive symptoms in a 6-month randomized controlled study.
- Published In:
- Journal of substance use and addiction treatment, 169, 209607 (2025)
- Authors:
- Chung, Albert Kar Kin, Tse, Cheuk Yin, Yeung, Gladys Kwan Yin, Tang, Sau Wan, Chan, Wing-Man, Law, Johnson Kai Chun
- Database ID:
- RTHC-06226
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 the antidepressant help cannabis users?
Clinicians observed mood improvement over 6 months, but patients did not report less anxiety or depression themselves, and cannabis use did not change.
Is vortioxetine a treatment for cannabis use disorder?
This pilot does not support it as a treatment for cannabis dependence itself, though it may help with comorbid mood symptoms.
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Cite This Study
https://rethinkthc.com/research/RTHC-06226APA
Chung, Albert Kar Kin; Tse, Cheuk Yin; Yeung, Gladys Kwan Yin; Tang, Sau Wan; Chan, Wing-Man; Law, Johnson Kai Chun. (2025). Vortioxetine improves illness severity for cannabis users with anxiety and depressive symptoms in a 6-month randomized controlled study.. Journal of substance use and addiction treatment, 169, 209607. https://doi.org/10.1016/j.josat.2024.209607
MLA
Chung, Albert Kar Kin, et al. "Vortioxetine improves illness severity for cannabis users with anxiety and depressive symptoms in a 6-month randomized controlled study.." Journal of substance use and addiction treatment, 2025. https://doi.org/10.1016/j.josat.2024.209607
RethinkTHC
RethinkTHC Research Database. "Vortioxetine improves illness severity for cannabis users wi..." RTHC-06226. Retrieved from https://rethinkthc.com/research/chung-2025-vortioxetine-improves-illness-severity
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.