Study Results
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View full resultsBasic Information
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COMPLETED
PHASE4
49 participants
INTERVENTIONAL
2013-05-01
2017-03-29
Brief Summary
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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.
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Detailed Description
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The overarching idea behind this proposal, however, is that CLOZ's use is being unreasonably restricted and should be made more widely available for patients with SCZ who have a co-occurring CUD but whose psychosis is not necessarily treatment resistant. This notion is supported by our preliminary clinical and animal data on the effects of CLOZ, as well as our neurobiological model of the basis of cannabis use in patients with SCZ that provides a pharmacologic rationale for this effect of CLOZ.
Even given all the arguments favoring the potential benefits of CLOZ in patients with SCZ and CUD, however, its side effect profile will likely limit its use until a fully powered study demonstrates its ability to decrease cannabis use in patients with SCZ. This proposal aims to launch such a study. If, as we hypothesize, this study confirms and extends our previous preliminary data of the effects of CLOZ in patients with SCZ and CUD, it will provide a strong impetus to expand the use of CLOZ in this population.
In the proposed study, 132 patients who are comorbid for both SCZ and CUD will be randomized to a 12-week treatment course with either CLOZ or risperidone (RISP) to test the hypothesis that patients treated with CLOZ will have decreased cannabis use as compared to patients treated with RISP. In addition, the study will determine whether patients treated with CLOZ will have improvements in psychiatric symptoms, quality of life neuropsychological functions as compared to those taking RISP. We will also explore whether patients taking CLOZ show improved reward responsiveness as compared to those taking RISP. Finally, this study will explore whether those patients with the val/val genotype at the Catechol-O-methyltransferase (COMT) Val158Met locus are more likely to decrease cannabis use during CLOZ treatment than are those without the val/val COMT genotype.
Should this study indicate that CLOZ will lessen cannabis use in patients with SCZ more than RISP, it will provide evidence needed to begin to shift clinical practice toward its use in these patients.
Conditions
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Study Design
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RANDOMIZED
PARALLEL
TREATMENT
QUADRUPLE
Study Groups
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Clozapine
The blinded CLOZ will be titrated on a recommended standard schedule, supervised by a study physician (or other prescriber) who can make the necessary adjustments to account for symptom control and tolerability. The titration is recommended to begin at 12.5 mg and then increase while the open-label base antipsychotic is tapered with a recommended goal of decreasing the base antipsychotic by 25% each week. If clinically tolerated, the target dose of CLOZ is 400 mg/day.
Clozapine
Clozapine: target dose of 400mg per day with a maximum dose of 550mg per day
Risperidone
The blinded RISP will also be titrated in the first weeks, using a titration schedule, with a target dose of 4 mg/day, while the open label base antipsychotic is tapered in a similar fashion.
Risperidone
Clozapine: target dose of 4mg per day with a maximum dose of 6mg per day
Interventions
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Clozapine
Clozapine: target dose of 400mg per day with a maximum dose of 550mg per day
Risperidone
Clozapine: target dose of 4mg per day with a maximum dose of 6mg per day
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* Clinical diagnosis of a cannabis use disorder (abuse or dependence)
Exclusion Criteria
* History of a seizure disorder
* Current treatment with clozapine or risperidone
* Contraindication to treatment with clozapine or risperidone
18 Years
55 Years
ALL
No
Sponsors
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University of South Carolina
OTHER
Michigan State University
OTHER
University of Miami
OTHER
University of Massachusetts, Worcester
OTHER
Dartmouth-Hitchcock Medical Center
OTHER
Responsible Party
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Principal Investigators
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Alan I Green, MD
Role: STUDY_CHAIR
Dartmouth College
Locations
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CNS Network Inc
Garden Grove, California, United States
Pacific Research Partners
Oakland, California, United States
University of Miami
Miami, Florida, United States
Unversity of Massachusetts Medical School
Worcester, Massachusetts, United States
Michigan State University / Cherry Street Health Services
Grand Rapids, Michigan, United States
Dartmouth Hitchcock Medical Center
Lebanon, New Hampshire, United States
University of North Carolina/UNC Center for Excellence in Community Mental Health
Raleigh, North Carolina, United States
University of South Carolina
Columbia, South Carolina, United States
Rutland Regional Medical Center
Rutland, Vermont, United States
Countries
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Provided Documents
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Document Type: Study Protocol and Statistical Analysis Plan
Other Identifiers
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1R01DA032533-01A1 D13012
Identifier Type: -
Identifier Source: org_study_id
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