Temporal association of cannabis use with symptoms in individuals at clinical high risk for psychosis.
BACKGROUND
Cannabis use is reported to increase the risk for psychosis, but no prospective study has longitudinally examined drug use and symptoms concurrently in clinical high risk cases.


METHODS
We prospectively followed for up to 2 years 32 cases who met research criteria for prodromal psychosis to examine the relationship between substance use and clinical measures.


RESULTS
Cases with a baseline history of cannabis use (41%) were older, but did not differ in clinical measures. Longitudinal assessments showed these cases had significantly more perceptual disturbances and worse functioning during epochs of increased cannabis use that were unexplained by concurrent use of other drugs or medications.


CONCLUSIONS
These data demonstrate that cannabis use may be a risk factor for the exacerbation of subthreshold psychotic symptoms, specifically perceptual disturbances, in high risk cases.
Corcoran
Cheryl M
CM
Columbia University, Department of Psychiatry, New York, NY, United States. cc788@columbia.edu
Kimhy
David
D
Stanford
Arielle
A
Khan
Shamir
S
Walsh
Julie
J
Thompson
Judy
J
Schobel
Scott
S
Harkavy-Friedman
Jill
J
Goetz
Ray
R
Colibazzi
Tiziano
T
Cressman
Victoria
V
Malaspina
Dolores
D
D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000453:epidemiology; D015897:Comorbidity; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D010468:Perceptual Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology; D012720:Severity of Illness Index