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

Northwell Health

Status and phase

Completed

Phase 4

Conditions

Cannabis Dependence

Treatments

Behavioral: Behavioral Intervention

Study type

Interventional

Funder types

Other

NIH

Identifiers

NCT01153490

10-159B

Details and patient eligibility

About

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.

Enrollment

124 patients

Sex

All

Ages

18 to 65 years old

Volunteers

No Healthy Volunteers

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