Improving Substance Use & Clinical Outcomes in Heavy Cannabis Users With

Status Completed

Clinical Trial Summary

Cannabis is the most used illicit substance in the United States. Previous studies suggest that atypical antipsychotics decrease the frequency and the amount of substance use in subjects with and without psychotic illness. So far, there are no controlled studies assessing the effectiveness of atypical antipsychotics for decreasing cannabis and other substance use in individuals with cannabis use disorders. The investigators postulate that the atypical antipsychotic quetiapine ER is an effective agent for improving substance use outcomes in subjects with cannabis use disorders. In this pilot study, the investigators will test this hypothesis in heavy cannabis users (i.e., individuals who are cannabis dependent and smoke three times or more per week). Because 50% of these heavy cannabis users report histories of psychotic experiences (i.e., attenuated positive symptoms) while smoking and are at risk for recurring psychotic symptoms, the investigators will focus this pilot clinical trial on this subgroup of cannabis users in order to increase the risk/benefit ratio of this study and target a population that may also benefit from the antipsychotic effect of quetiapine ER. Considering the lack of controlled studies assessing the efficacy of atypical antipsychotics in heavy cannabis users, assessing the effectiveness of an atypical antipsychotic medication on substance use and clinical outcomes in this population is critical for improving the prognosis of these individuals.

Thus, the aims of this randomized, double-blind, placebo-controlled study are to assess the efficacy of an atypical antipsychotic (quetiapine ER) in 120 subjects with cannabis dependence, a recent history (within a year) of attenuated psychotic symptoms, and using cannabis 3 times or more per week for: (1) decreasing the use of cannabis and other substances; and (2) preventing the recurrence of psychotic experiences. The investigators will also assess the effects of quetiapine ER on craving and mood, and its tolerability. This project will be a 12-week, randomized, double-blind, placebo-controlled study with quetiapine ER and it will include a comprehensive assessment of symptoms, substance use, and side effects.

This study will benefit the field by providing unique data on the relative efficacy and tolerability of treatment with atypical antipsychotics in heavy cannabis users with a vulnerability to psychosis. This study will be the basis for future studies assessing the long-term efficacy and tolerability of atypical antipsychotics in individuals with cannabis use disorders.

Clinical Trial Description

n/a

Study Design

Related Conditions & MeSH terms

Clinical Trial Details

NCT number	NCT01153490
Study type	Interventional
Source	Northwell Health
Contact
Status	Completed
Phase	Phase 4
Start date	October 22, 2010
Completion date	August 6, 2012

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See also
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Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.

Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.

Improving Substance Use and Clinical Outcomes in Heavy Cannabis Users With Quetiapine — CD

Clinical Trial Summary

Clinical Trial Description

Study Design

Related Conditions & MeSH terms