Improving Substance Use and Clinical Outcomes in Heavy Cannabis Users With Quetiapine
| Status: | Completed |
|---|---|
| Conditions: | Psychiatric |
| Therapuetic Areas: | Psychiatry / Psychology |
| Healthy: | No |
| Age Range: | 18 - 65 |
| Updated: | 4/2/2016 |
| Start Date: | July 2010 |
| End Date: | June 2012 |
| Contact: | Christina E Ryan, B.A. |
| Email: | cryan3@nshs.edu |
| Phone: | 718-470-4255 |
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.
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.
Inclusion Criteria:
- DSM-IV-defined diagnosis of cannabis dependence (304.30) assessed with the Structured
Clinical Interview for Axis I DSM-IV Disorders (SCID-I/P) (First 1998))
- one or more attenuated positive symptoms with a score 3 ('moderate'), 4 ('moderate
severe'), or 5 ('severe but not psychotic') during the past year assessed with the
Structured Interview for Prodromal Syndromes (SIPS) and the Scale of Prodromal
Symptoms (SOPS) (McGlashan et al, 2001)
- lifetime treatment with antipsychotic medication less than 2 weeks
- cannabis use for more than one year
- cannabis use three or more days per week on average for the past 3 months
- aged 18 to 65
- competent and willing to sign informed consent
- for women, a negative urine pregnancy test and agreement to use a medically accepted
method of birth control during the study.
Exclusion Criteria:
- DSM-IV criteria for schizophrenia, schizophreniform disorder, schizoaffective
disorder, a psychotic disorder due to a general medical condition, psychosis NOS,
delusional disorder, brief psychotic disorder, shared psychotic disorder, or a mood
disorder (major depression or bipolar) with psychotic features assessed with the
Structured Clinical Interview for Axis I DSM-IV Disorders (SCID-I/P) (First 1998)
- DSM-IV diagnosis of any psychoactive substance dependence other than cannabis or
nicotine
- being in an environment with no access to cannabis (e.g., hospitalization,
residential treatment, jail, ..) for more than one week during the past three months
preceding study entry
- serious neurological or endocrine disorder or any medical condition or treatment
known to affect the brain
- use of medications that have an effect on monoamines (e.g., antidepressants
- severe medical or physical illnesses
- criteria of the National Cholesterol Education Program (NCEP) for a metabolic
syndrome (Expert panel on Detection, Evaluation, and Treatment of High Blood
Cholesterol in Adults, 2001)
- medical condition that requires treatment with a medication that has psychotropic
effects
- significant risk of suicidal or homicidal behavior
- cognitive or language limitations, or any other factor that would preclude subjects
providing informed consent or participating in study procedures
- treatment with medications for addiction
- treatment with medication having a risk of addiction (e.g., benzodiazepines,
barbiturates)
- history of treatment resistance to quetiapine ER
- medical contraindications to quetiapine ER
- hypersensitivity to quetiapine ER or any of its component
- for women, pregnant, breastfeeding, or intention to become pregnant during the study
timeframe
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