title: Cannabis use and vulnerability for psychosis in early adolescence--a TRAILS study.
abstract: OBJECTIVE
  To examine the direction of the longitudinal association between vulnerability for psychosis and cannabis use throughout adolescence.
  
  
  METHODS
  Cross-lagged path analysis was used to identify the temporal order of vulnerability for psychosis and cannabis use, while controlling for gender, family psychopathology, alcohol use and tobacco use.
  
  
  METHODS
  A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey (TRAILS) study].
  
  
  METHODS
  A total of 2120 adolescents with assessments at (mean) age 13.6, age 16.3 and age 19.1.
  
  
  METHODS
  Vulnerability for psychosis at the three assessment points was represented by latent factors derived from scores on three scales of the Youth Self-Report and the Adult Self-Report, i.e. thought problems, social problems and attention problems. Participants self-reported on cannabis use during the past year at all three waves.
  
  
  RESULTS
  Significant associations (r = 0.12-0.23) were observed between psychosis vulnerability and cannabis use at all assessments. Also, cannabis use at age 16 predicted psychosis vulnerability at age 19 (Z = 2.6, P < 0.05). Furthermore, psychosis vulnerability at ages 13 (Z = 2.0, P < 0.05) and 16 (Z = 3.0, P < 0.05) predicted cannabis use at, respectively, ages 16 and 19.
  
  
  CONCLUSIONS
  Cannabis use predicts psychosis vulnerability in adolescents and vice versa, which suggests that there is a bidirectional causal association between the two.
authors.affiliation: Department of Clinical Child and Adolescent Studies, Faculty of Social Sciences, Leiden University, Leiden, the Netherlands. mlendering@fsw.leidenuniv.nl
authors.forename: Merel F H
authors.initials: MF
authors.lastname: Griffith-Lendering
authors.forename: Johanna T W
authors.initials: JT
authors.lastname: Wigman
authors.forename: Andrea
authors.initials: A
authors.lastname: Prince van Leeuwen
authors.forename: Stephan C J
authors.initials: SC
authors.lastname: Huijbregts
authors.forename: Anja C
authors.initials: AC
authors.lastname: Huizink
authors.forename: Johan
authors.initials: J
authors.lastname: Ormel
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
authors.forename: Jim
authors.initials: J
authors.lastname: van Os
authors.forename: Hanna
authors.initials: H
authors.lastname: Swaab
authors.forename: Wilma A M
authors.initials: WA
authors.lastname: Vollebergh
mesh_terms: D000293:Adolescent; D001288:Attention / Q000187:drug effects; D005260:Female; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D002189:Marijuana Abuse / Q000523:psychology*; D011446:Prospective Studies; D011569:Psychiatric Status Rating Scales; D011618:Psychotic Disorders / Q000209:etiology*; D012423:Rural Health; D057566:Self Report; D012959:Socioeconomic Factors; D014504:Urban Health; D055815:Young Adult