Treatment of Schizophrenia and Comorbid Cannabis Use Disorder: Comparing Clozapine to Treatment-as-Usual
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|ClinicalTrials.gov Identifier: NCT00498550|
Recruitment Status : Completed
First Posted : July 10, 2007
Results First Posted : January 19, 2012
Last Update Posted : March 13, 2019
|Condition or disease||Intervention/treatment||Phase|
|Schizophrenia Dual Diagnosis Schizoaffective Disorder Psychotic Disorder Cannabis Abuse||Drug: Clozapine Drug: Treatment as usual||Phase 4|
Individuals with schizophrenia have a high risk of becoming addicted to drugs; between 13 to 42% of schizophrenics are addicted to marijuana. These individuals often have difficulties adhering to a substance abuse treatment program, and have an increased chance of marijuana relapse. Marijuana use by schizophrenics has also been associated with clinical exacerbations, noncompliance with antipsychotic medications, poor global functioning, and increased rehospitalization rates. While antipsychotic medications are often effective in controlling symptoms of schizophrenia, they are not always effective in preventing substance abuse. Clozapine, an atypical antipsychotic drug, is currently used to treat schizophrenia. Preliminary research has shown that clozapine is more successful at reducing drug relapse rates in individuals with schizophrenia, as compared to other antipsychotic medications, including olanzapine and risperidone. The purpose of this study is to compare the effectiveness of clozapine as compared to other oral antipsychotic treatment, including combinations of up to two antipsychotics, in reducing marijuana use in schizophrenic individuals.
This study will enroll individuals with schizophrenia who are currently taking any oral antipsychotic other than clozapine, including those taking up to two oral antipsychotic, and who are also addicted to marijuana. The study will begin with a 1-week assessment phase, during which all participants will continue taking olanzapine or risperidone. Participants will undergo a physical examination and have blood drawn for laboratory tests. Information pertaining to their medical, psychiatric, and substance use history will also be collected. Urine tests and breathalyzers will be used to screen for the presence of alcohol and drugs. Following the assessment phase, participants will be randomly assigned to switch to clozapine or remain on their prestudy antipsychotic for 12 weeks. Participants remaining on their prestudy antipsychotic treatment will continue to receive the same dose for the entire study. Participants taking clozapine will initially receive a daily dose of 12.5 mg, which will be increased to a maximum of 400 mg per day, as tolerated. Study visits will take place once a week. At each visit, medication side effects, physical and psychological symptoms, substance use, treatment services received, and living situation will be assessed. Blood will be drawn for laboratory tests. Drug and alcohol levels will be monitored three times a week through urine and breathalyzer tests. Quality of life questionnaires will be administered once a month.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||31 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Single (Outcomes Assessor)|
|Official Title:||Cannabis and Schizophrenia: Effects of Clozapine|
|Study Start Date :||October 2000|
|Actual Primary Completion Date :||March 2009|
|Actual Study Completion Date :||March 2009|
Clozapine up to 550mg per day
Other Name: Clozaril
Active Comparator: Treatment as usual
Treatment as usual with any antipsychotic other than Clozapine.
Drug: Treatment as usual
Remain on pre-study antipsychotic treatment
- Average Over Time of Intensity of Cannabis Use (Used to Evaluate Treatment Efficacy) [ Time Frame: Week 1 to week 12 ]Intensity of cannabis use is obtained for each week retrospectively as the number of joints smoked during the prior week (assessed by the Timeline Followback Scale). Mixed models are used to obtain estimates of efficacy from the partial data provided by each subject while adherent to assigned treatment (under the 'missing at random' assumption). The 'explanatory' estimands (target of the mixed model estimation) are defined in terms of population quantities that would have occurred had all subjects remained on assigned treatment throughout the study. The point estimate for each arm is reported under Number.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00498550
|United States, California|
|West LA VAHCS|
|Los Angeles, California, United States, 90073|
|United States, Missouri|
|Kansas City, Missouri, United States, 64108|
|United States, New Hampshire|
|Mental Health Center of Greater Manchester|
|Manchester, New Hampshire, United States, 03101|
|United States, South Carolina|
|University South Carolina|
|Columbia, South Carolina, United States, 29203|
|Principal Investigator:||Alan Green, MD||Dartmouth-Hitchcock Medical Center|