Antidepressant vortioxetine improved clinician-rated mood in cannabis users but did not reduce cannabis use | Research

The takeaway

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.

Addiction psychiatrists, clinicians treating dual diagnosis patients

Clinician-rated mood improved (p<.05) but self-reported symptoms and cannabis use did not change

What the researchers 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.

Why it 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 numbers in context

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 the study worked

6-month prospective RCT; 30 cannabis users with anxiety/depressive symptoms randomized to vortioxetine (n=11) or standard treatment (n=19).

What this study cannot 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.

How to read the evidence

Randomized design but very small sample, unequal groups, and lack of placebo limit conclusions.

When this study was published

Published 2025

The bigger picture

Treating comorbid mood symptoms in cannabis users may improve engagement with treatment even if cannabis use itself does not change.

Questions still open

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?

Common 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.

Read the original research

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

View on PubMed ↗Publisher’s paper ↗

Citation

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