title: Early exposure to cannabis and risk for psychosis in young adolescents in Trinidad.
abstract: OBJECTIVE
  Cannabis use increases the risk for psychosis, but psychotogenic effects of cannabis may be restricted to exposure during early adolescence.
  
  
  METHODS
  Four hundred and seventy-two participants (aged 12-23 years), randomly selected from the general population in Trinidad, completed questionnaires on past and current cannabis use and psychotic symptoms (using the Community Assessment of Psychic Experiences).
  
  
  RESULTS
  Cannabis use increased the risk of experiencing psychotic symptoms and this effect was conditional on early exposure, defined around the mean age of onset of cannabis use. Thus, exposure before but not after the age of 14 years predicted psychotic symptoms (respectively beta: 0.71, 95% CI 0.22; 1.19, P = 0.004 and beta: -0.11, 95% CI -0.57; 0.36, P = 0.66). The developmental effect of cannabis use was independent of use of other drugs or current use of cannabis.
  
  
  CONCLUSIONS
  Early adolescence may be a critical period with regard to the psychotogenic effect of cannabis across geographical settings and ethnic groups.
authors.affiliation: Department of Psychiatry, GGZ Eindhoven, Eindhoven, the Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Konings
authors.forename: C
authors.initials: C
authors.lastname: Henquet
authors.forename: H D
authors.initials: HD
authors.lastname: Maharajh
authors.forename: G
authors.initials: G
authors.lastname: Hutchinson
authors.forename: J
authors.initials: J
authors.lastname: Van Os
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000523:psychology / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology*; D008385:Marijuana Smoking / Q000009:adverse effects* / Q000453:epidemiology; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011618:Psychotic Disorders / Q000453:epidemiology*; D012307:Risk Factors; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D014300:Trinidad and Tobago / Q000453:epidemiology; D055815:Young Adult