Phase 4 N=49 Randomized Quadruple-blind Treatment

Clozapine for Cannabis Use in Schizophrenia

Schizophrenia · Cannabis Abuse · Cannabis Dependence · Dual Diagnosis

Bottom Line

View on ClinicalTrials.gov: NCT01639872 ↗

Enrolled (actual)

Serious AEs

12.8%

Results posted

Dec 2019

Primary outcome: Primary: Average Over Time of Intensity of Cannabis Use (Used to Evaluate Treatment Efficacy) — 10.21; 10.2 joints smoked during the prior week — p=.99

Study Design & Population

Study type: Interventional
Phase: Phase 4
Interventions: Clozapine (Drug); Risperidone (Drug)
Age: Adult · 18+ yrs
Sex: All
Sponsor: Dartmouth-Hitchcock Medical Center
Primary completion: Mar 2017

Outcome Measures

Outcome	Result	p-value
PRIMARY Average Over Time of Intensity of Cannabis Use (Used to Evaluate Treatment Efficacy)	10.21; 10.2	.99
PRIMARY Average Over Time of Frequency of Cannabis Use	4.26; 4.58	.25

Summary

Many individuals with schizophrenia also suffer from marijuana addiction that worsens their problems related to schizophrenia. Most of the medications prescribed for schizophrenia have no effect on reducing marijuana use. Preliminary data suggests that clozapine, an atypical antipsychotic, may limit marijuana use in people diagnosed with schizophrenia, but it is not commonly used due to its side effects and is reserved for people who do not respond to other antipsychotic medications. In the proposed study, 132 individuals who are diagnosed with both schizophrenia and a cannabis use disorder will be randomized to a 12-week treatment course with either clozapine or risperidone (another commonly prescribed antipsychotic medication) to test the hypothesis that patient treated with clozapine will have decreased cannabis use as compared to patients treated with risperidone. Should this study indicate that clozapine will lessen marijuana use in persons diagnosed with schizophrenia more than risperidone, it will provide evidence needed to begin to shift clinical practice toward its use in this population.

Eligibility Criteria

Inclusion Criteria

Clinical diagnosis of schizophrenia
Clinical diagnosis of a cannabis use disorder (abuse or dependence)

Exclusion Criteria

Pregnant,trying to become pregnant or nursing
History of a seizure disorder
Current treatment with clozapine or risperidone
Contraindication to treatment with clozapine or risperidone

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT01639872). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.