Buspirone Showed Modest Promise for Treating Marijuana Dependence in a Small Trial | Research

The takeaway

In a 12-week placebo-controlled trial, buspirone showed a trend toward more negative drug tests compared to placebo, with a significant effect among participants who completed the full trial.

Read this if you are looking for medication options to help quit cannabis.

18 percentage point improvement in drug tests with buspirone (p=0.071 overall, p=0.014 in completers)

What the researchers found

Fifty participants with marijuana dependence received either buspirone (up to 60 mg/day) or placebo for 12 weeks alongside motivational interviewing.

In the full intent-to-treat analysis, the buspirone group had 18 percentage points more negative urine drug screens than placebo, though this did not reach statistical significance (p=0.071).

Self-reported marijuana-free days did not differ between groups (45.2% vs 51.4%).

However, among participants who completed all 12 weeks, buspirone produced a significantly higher percentage of negative drug tests (p=0.014) and a trend toward reaching the first negative test sooner (p=0.054).

Retention in the study was a major challenge, limiting statistical power.

Why it matters

No FDA-approved medication exists for cannabis use disorder. This was an early exploration of whether an anti-anxiety medication could help, based on the idea that anxiety contributes to continued cannabis use.

The numbers in context

23 buspirone, 27 placebo. 12-week trial. 18 percentage point difference in negative drug tests (not significant, p=0.071). Among completers: significant difference (p=0.014). Self-report showed no difference.

How the study worked

Randomized, double-blind, placebo-controlled trial. 23 participants received buspirone (maximum 60 mg/day) and 27 received placebo for 12 weeks. Both groups received motivational interviewing. Outcomes included urine drug screens and self-reported use.

What this study cannot tell us

Small sample with high dropout rates. The completer analysis showing significance is subject to selection bias. Self-report and urine test results conflicted. Buspirone dose was variable up to 60 mg/day.

How to read the evidence

Small randomized controlled trial (n=50) with high dropout rates that limited statistical power. Intent-to-treat analysis did not reach significance.

When this study was published

Published in 2009. Subsequent cannabis cessation medication trials have explored other compounds, but no FDA-approved pharmacotherapy for cannabis use disorder has been established as of the time of this writing.

The bigger picture

Finding effective medications for cannabis dependence remains an ongoing challenge. This trial, while underpowered, suggested buspirone warranted further study, though retention problems highlighted the difficulty of conducting cannabis cessation trials.

Questions still open

Would a larger trial with better retention confirm buspirone efficacy? Is the discrepancy between urine tests and self-report a measurement issue? Would combining buspirone with different behavioral interventions improve outcomes?

Common questions

What is buspirone?

Buspirone is an anti-anxiety medication that works differently from benzodiazepines. It was tested for cannabis dependence because anxiety often drives continued cannabis use, and reducing anxiety might help people quit.

Why did self-report and drug tests give different results?

Self-reported drug use is often unreliable, particularly in treatment settings where participants may underreport use. Urine drug screens provide objective confirmation but only detect use within a limited time window.

Read the original research

A placebo-controlled trial of buspirone for the treatment of marijuana dependence.

Drug and alcohol dependence, 105(1-2), 132-8

View on PubMed ↗Publisher’s paper ↗

Citation

McRae-Clark, Aimee L; Carter, Rickey E; Killeen, Therese K; Carpenter, Matthew J; Wahlquist, Amy E; Simpson, Stacey A; Brady, Kathleen T. (2009). A placebo-controlled trial of buspirone for the treatment of marijuana dependence.. Drug and alcohol dependence, 105(1-2), 132-8. https://doi.org/10.1016/j.drugalcdep.2009.06.022