Cannabis use and misuse prevalence among people with psychosis.
BACKGROUND
Increasing attention has been given by researchers to cannabis use in individuals with psychosis. As psychoses are relatively low-prevalence disorders, research has been mostly been restricted to small-scale studies of treatment samples. The reported prevalence estimates obtained from these studies vary widely.


OBJECTIVE
To provide prevalence estimates based on larger samples and to examine sources of variability in prevalence estimates across studies.


METHODS
Data from 53 studies of treatment samples and 5 epidemiological studies were analysed.


RESULTS
Based on treatment sample data, prevalence estimates were calculated for current use (23.0%), current misuse (11.3%), 12-month use (29.2%), 12-month misuse (18.8%), lifetime use (42.1%) and lifetime misuse (22.5%). Epidemiological studies consistently reported higher cannabis use and misuse prevalence in people with psychosis.


CONCLUSIONS
The factor most consistently associated with increased odds of cannabis prevalence was specificity of diagnosis. Factors such as consumption patterns and study design merit further consideration.
Green
Bob
B
Community Forensic Mental Health Service, 42 Albert Street, Brisbane 4001, Australia. bob_green@health.qld.gov.au
Young
Ross
R
Kavanagh
David
D
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D017831:Diagnosis, Dual (Psychiatry); D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000652:urine; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000652:urine; D008875:Middle Aged; D015995:Prevalence; D011618:Psychotic Disorders / Q000453:epidemiology* / Q000652:urine; D018401:Sample Size