No Antipsychotic Was Clearly Better Than Risperidone for Psychosis Patients Who Also Use Substances
A Cochrane review of 8 trials (1,073 participants) found no clear differences between risperidone and other antipsychotics for people with dual diagnosis, though clozapine showed lower cannabis craving in one small trial.
Quick Facts
What This Study Found
No clear differences between risperidone and clozapine, olanzapine, perphenazine, quetiapine, or ziprasidone on psychotic symptoms, substance use reduction, or study completion in dual diagnosis patients. One small trial (n=28) found clozapine was associated with lower cannabis craving than risperidone.
Key Numbers
8 RCTs, 1,073 participants. All evidence rated very low to low quality by GRADE criteria. Clozapine showed lower cannabis craving (MD 7.00, 95% CI 2.37-11.63) in one trial of 28 patients.
How They Did This
Cochrane systematic review of 8 RCTs with 1,073 participants comparing risperidone to other antipsychotics in people with serious mental illness and co-occurring substance misuse. GRADE quality assessment applied.
Why This Research Matters
Up to 75% of people with serious mental illness have co-occurring substance use disorders. Clinicians need evidence to guide antipsychotic choice in this common scenario, but this review found the evidence base is insufficient to make recommendations.
The Bigger Picture
The absence of good evidence for antipsychotic choice in dual diagnosis is a significant gap given how common this comorbidity is. The hint that clozapine may reduce cannabis craving is intriguing but needs replication.
What This Study Doesn't Tell Us
Very low to low quality evidence throughout. Most trials were small, secondary analyses of larger studies, or subgroup analyses. Heterogeneous study designs. Missing data on important outcomes like metabolic effects and quality of life.
Questions This Raises
- ?Does clozapine genuinely reduce cannabis craving more than other antipsychotics?
- ?Would larger, purpose-designed trials find meaningful differences?
- ?Should antipsychotic selection in dual diagnosis prioritize substance use outcomes?
Trust & Context
- Key Stat:
- Up to 75% of people with serious mental illness have co-occurring substance use, yet evidence to guide antipsychotic choice in this population remains very low quality.
- Evidence Grade:
- Preliminary - Cochrane review is rigorous methodology, but all available evidence was rated very low to low quality by GRADE standards.
- Study Age:
- Published in 2018. Literature searched through October 2017.
- Original Title:
- Risperidone versus other antipsychotics for people with severe mental illness and co-occurring substance misuse.
- Published In:
- The Cochrane database of systematic reviews, 1(1), CD011057 (2018)
- Authors:
- Temmingh, Henk S(2), Williams, Taryn, Siegfried, Nandi(2), Stein, Dan J
- Database ID:
- RTHC-01852
Evidence Hierarchy
Combines results from multiple studies to find an overall pattern.
What do these levels mean? →Frequently Asked Questions
Which antipsychotic is best for patients who also use cannabis?
This Cochrane review found insufficient evidence to recommend one antipsychotic over another for dual diagnosis patients. One small trial suggested clozapine might reduce cannabis craving more than risperidone, but this needs confirmation.
How common is dual diagnosis (mental illness plus substance use)?
Up to 75% of people with serious mental illness like schizophrenia have co-occurring substance use disorders, making dual diagnosis the norm rather than the exception. Despite this, evidence for optimal treatment is lacking.
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Cite This Study
https://rethinkthc.com/research/RTHC-01852APA
Temmingh, Henk S; Williams, Taryn; Siegfried, Nandi; Stein, Dan J. (2018). Risperidone versus other antipsychotics for people with severe mental illness and co-occurring substance misuse.. The Cochrane database of systematic reviews, 1(1), CD011057. https://doi.org/10.1002/14651858.CD011057.pub2
MLA
Temmingh, Henk S, et al. "Risperidone versus other antipsychotics for people with severe mental illness and co-occurring substance misuse.." The Cochrane database of systematic reviews, 2018. https://doi.org/10.1002/14651858.CD011057.pub2
RethinkTHC
RethinkTHC Research Database. "Risperidone versus other antipsychotics for people with seve..." RTHC-01852. Retrieved from https://rethinkthc.com/research/temmingh-2018-risperidone-versus-other-antipsychotics
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.