title: Cannabis use and cognitive functions in at-risk mental state and first episode psychosis.
abstract: BACKGROUND
  Meta-analyses suggest that schizophrenia patients with a history of cannabis use have less impaired cognitive functioning compared to patients without cannabis use.
  
  
  OBJECTIVE
  The objective of this study was to assess the association between recency and frequency of cannabis use and cognitive functioning in at-risk mental state for psychosis (ARMS) and first episode psychosis (FEP) individuals.
  
  
  METHODS
  One hundred thirty-six participants completed a cognitive test battery and were assessed for current and past cannabis use. Analyses of covariance models were applied to evaluate the main effects of cannabis use and patient group (ARMS vs. FEP) as well as their interactions on cognitive functioning.
  
  
  RESULTS
  No differences were observed in cognitive performance between current, former, and never users, and there were no significant interactions between cannabis use and patient group. Furthermore, within the group of current cannabis users, the frequency of cannabis use was not significantly associated with cognitive functioning.
  
  
  CONCLUSIONS
  The results of the present study do not support the notion that FEP patients and ARMS individuals with a history of cannabis use have less impaired cognitive functioning compared to those without cannabis use.
authors.affiliation: Center for Gender Research and Early Detection, University of Basel Psychiatric Clinics, c/o University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Bugra
authors.forename: E
authors.initials: E
authors.lastname: Studerus
authors.forename: C
authors.initials: C
authors.lastname: Rapp
authors.forename: C
authors.initials: C
authors.lastname: Tamagni
authors.forename: J
authors.initials: J
authors.lastname: Aston
authors.forename: S
authors.initials: S
authors.lastname: Borgwardt
authors.forename: A
authors.initials: A
authors.lastname: Riecher-Rössler
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D003071:Cognition / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000453:epidemiology*; D009483:Neuropsychological Tests; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000503:physiopathology*; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult