title: Temporal association of cannabis use with symptoms in individuals at clinical high risk for psychosis.
abstract: 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.
authors.affiliation: Columbia University, Department of Psychiatry, New York, NY, United States. cc788@columbia.edu
authors.forename: Cheryl M
authors.initials: CM
authors.lastname: Corcoran
authors.forename: David
authors.initials: D
authors.lastname: Kimhy
authors.forename: Arielle
authors.initials: A
authors.lastname: Stanford
authors.forename: Shamir
authors.initials: S
authors.lastname: Khan
authors.forename: Julie
authors.initials: J
authors.lastname: Walsh
authors.forename: Judy
authors.initials: J
authors.lastname: Thompson
authors.forename: Scott
authors.initials: S
authors.lastname: Schobel
authors.forename: Jill
authors.initials: J
authors.lastname: Harkavy-Friedman
authors.forename: Ray
authors.initials: R
authors.lastname: Goetz
authors.forename: Tiziano
authors.initials: T
authors.lastname: Colibazzi
authors.forename: Victoria
authors.initials: V
authors.lastname: Cressman
authors.forename: Dolores
authors.initials: D
authors.lastname: Malaspina
mesh_terms: 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