Prospective study of cannabis use in adolescents at clinical high risk for psychosis: impact on conversion to psychosis and functional outcome.
BACKGROUND
Clinical and epidemiological studies suggest an association between cannabis use and psychosis but this relationship remains controversial.


METHODS
Clinical high-risk (CHR) subjects (age 12-22 years) with attenuated positive symptoms of psychosis (CHR+, n=101) were compared to healthy controls (HC, n=59) on rates of substance use, including cannabis. CHR+ subjects with and without lifetime cannabis use (and abuse) were compared on prodromal symptoms and social/role functioning at baseline. Participants were followed an average of 2.97 years to determine psychosis conversion status and functional outcome.


RESULTS
At baseline, CHR+ subjects had significantly higher rates of lifetime cannabis use than HC. CHR+ lifetime cannabis users (n=35) were older (p=0.015, trend), more likely to be Caucasian (p=0.002), less socially anhedonic (p<0.001) and had higher Global Functioning: Social (GF:Social) scores (p<0.001) than non-users (n=61). CHR+ cannabis users continued to have higher social functioning than non-users at follow-up (p<0.001) but showed no differences in role functioning. A small sample of CHR+ cannabis abusers (n=10) showed similar results in that abusers were older (p=0.008), less socially anhedonic (p=0.017, trend) and had higher baseline GF:Social scores (p=0.006) than non-abusers. Logistic regression analyses revealed that conversion to psychosis in CHR+ subjects (n=15) was not related to lifetime cannabis use or abuse.


CONCLUSIONS
The current data do not indicate that low to moderate lifetime cannabis use is a major contributor to psychosis or poor social and role functioning in clinical high-risk youth with attenuated positive symptoms of psychosis.
The Zucker Hillside Hospital, North Shore-Long Island Jewish Health System, Glen Oaks, NY 11004, USA. aauther@lij.edu
A M
AM
Auther
D
D
McLaughlin
R E
RE
Carrión
P
P
Nagachandran
C U
CU
Correll
B A
BA
Cornblatt
D000293:Adolescent; D017668:Age of Onset; D015984:Causality; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D009518:New York; D016017:Odds Ratio; D062706:Prodromal Symptoms; D011605:Psychoses, Substance-Induced / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D055815:Young Adult
D013287:Illicit Drugs