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. 2011;7(1-2):50-63.
doi: 10.1080/15504263.2011.570118.

A randomized trial of clozapine vs. other antipsychotics for cannabis use disorder in patients with schizophrenia

Mary F Brunette  1 , Ree Dawson  2 , Christopher D O'Keefe  1 , Meera Narasimhan  3 , Douglas L Noordsy  1 , Joanne Wojcik  4 , Alan I Green  1
Affiliations

A randomized trial of clozapine vs. other antipsychotics for cannabis use disorder in patients with schizophrenia

Mary F Brunette et al. J Dual Diagn. 2011.

Abstract

Objective: Cannabis use disorder is the most common co-occurring drug use disorder in people with schizophrenia and is associated with poor outcomes. We launched a randomized controlled trial to assess the impact of clozapine compared with treatment as usual on cannabis use in patients with schizophrenia and co-occurring cannabis use disorder.

Methods: Thirty-one patients with schizophrenia and co-occurring cannabis use disorder were randomly assigned to switch to clozapine or to stay on their current antipsychotic and were then followed weekly for 12 weeks. Blinded raters assessed participants weekly with the Timeline Follow-back for substance use and the expanded Brief Psychiatric Rating Scale for symptoms. Longitudinal random effects models were used to investigate the time-varying differences in cannabis use and other outcomes between the treatment as usual and clozapine groups.

Results: The two groups differed in average intensity of cannabis use by approximately 4.5 joints/week, with lesser use in the clozapine group (t = -1.77; df = 28.5; p=.086; effect size ~ 0.6). Symptoms and functioning were not different between the two groups.

Conclusions: Clozapine may reduce cannabis use among patients with schizophrenia and co-occurring cannabis use disorder. Further controlled trials are warranted.

Keywords: cannabis; clozapine; co-occurring; schizophrenia; substance use disorder; treatment.

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Conflict of interest statement

Disclosures

Dr. Brunette has no known conflict of interest. She has received funding for research from Bristol Meyers Squib Foundation.

Dr. Green reports research grant support from National Institute on Alcohol Abuse and Alcoholism, National Institute on Drug Abuse, National Institute of Mental Health, Janssen and Eli Lilly, Forest Laboratories and AstraZeneca. He also serves on a Data Safety Monitoring Board reviewing Eli Lilly studies, owns shares of stock in Johnson & Johnson, Pfizer and Mylan, and has two pending patents on the treatment of substance abuse.

Dr. Dawson has no known conflict of interest.

Mr. O’Keefe has no known conflict of interest.

Dr. Narasiman has no known conflict of interest. She has received research funding from National Institute on Drug Abuse, National Institute of Mental Health, Janssen, Forest, and Pfizer.

Dr. Noordsy has no known conflict of interest. He has received research funding and/or consulting or speaking honoraria from the following companies that make psychotropic medications: Astra Zeneca, Bristol Meyers Squib, Janssen, Eli Lilly, Lundbeck, Novartis, Merck, and Sunovion.

Dr. Wojcik has no known conflict of interest.

Figures

Figure 1
Figure 1
Intensity of cannabis use (joints per week) in patients on treatment as usual (TAU) and in patients switched to clozapine (CLOZ): explanatory analysis
Figure 2
Figure 2
Mean heavy drinking days (per week) in patients on treatment as usual (TAU) and in patients on clozapine (CLOZ): explanatory analysis
See this image and copyright information in PMC

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