Pilot trial of an antipsychotic medication for cannabis dependence showed reduced use and improved mood | Research

The takeaway

In 21 cannabis-dependent patients given low-dose pericyazine (an antipsychotic) for 4 weeks, cannabis use, depression, anxiety, and insomnia all significantly decreased, though the open-label design limits conclusions.

Read this if you are interested in medications being explored for cannabis dependence treatment.

Significant reductions in cannabis use, depression, anxiety, and insomnia

What the researchers found

Twenty-one patients with cannabis dependence received pericyazine, a low-potency antipsychotic with sedative properties and low abuse potential, for 4 weeks in a community clinic setting. The dosing was flexible, up to 20 mg daily (8 tablets of 2.5 mg).

Significant reductions were observed in cannabis use, depression, anxiety, and insomnia severity across the treatment period. Pericyazine appeared to be well tolerated and easily administered in community clinics.

However, without a placebo control group, the authors could not conclude that the medication itself caused the improvements. Placebo effects, natural recovery, and the supportive clinical setting could all have contributed.

Why it matters

With no approved medications for cannabis dependence, any preliminary positive signal deserves attention. Pericyazine's sedative properties could address cannabis withdrawal symptoms (insomnia, anxiety) while its low abuse liability made it safe for addiction populations.

The numbers in context

21 patients. 4-week treatment. Up to 20 mg/day pericyazine. Significant reductions in cannabis use, depression, anxiety, insomnia. Well tolerated.

How the study worked

Naturalistic open-label case series. 21 patients enrolled for 4-week pericyazine treatment (up to 20 mg/day). Weekly medical review. Cannabis use, depression, anxiety, and insomnia measured with validated tools at baseline and follow-up. ECG and blood monitoring for safety.

What this study cannot tell us

Open-label without placebo control. Very small sample. Only 4-week treatment period. Cannot attribute improvements to the medication. High likelihood of placebo effect and regression to the mean.

How to read the evidence

Open-label pilot without control group. Provides preliminary safety and feasibility data but cannot determine efficacy.

When this study was published

Published in 2012. Pericyazine has not subsequently been validated for cannabis dependence in a randomized trial.

The bigger picture

This reflected clinical pragmatism in some parts of Australia, where pericyazine was already being used off-label for cannabis dependence despite no trial evidence. The pilot provided preliminary justification for a proper randomized trial.

Questions still open

Would pericyazine outperform placebo in a randomized trial? Are the benefits sustained beyond 4 weeks? Would other low-potency antipsychotics work similarly?

Common questions

Is there a medication for cannabis dependence?

No medication has been approved for cannabis dependence. This pilot tested pericyazine (an antipsychotic) and saw improvements, but without a placebo comparison group, the improvements could have been due to other factors. A randomized trial would be needed.

Why would an antipsychotic help with cannabis dependence?

Pericyazine has sedative properties that could address cannabis withdrawal symptoms like insomnia and anxiety. Its low abuse potential made it safe for use in addiction populations. However, it was not confirmed as effective in this preliminary study.

Read the original research

Pericyazine in the treatment of cannabis dependence in general practice: a naturalistic pilot trial.

Substance abuse and rehabilitation, 3, 43-7

View on PubMed ↗Publisher’s paper ↗

Citation

Morley, Kirsten C; Haber, Paul S; Morgan, Madeleine L; Samara, Fares. (2012). Pericyazine in the treatment of cannabis dependence in general practice: a naturalistic pilot trial.. Substance abuse and rehabilitation, 3, 43-7. https://doi.org/10.2147/SAR.S30052