title: The familial aggregation of cannabis use disorders.
abstract: OBJECTIVE
  The aim of this paper is to examine the familial aggregation of cannabis use disorders and other psychiatric conditions among first-degree relatives and spouses of probands with a cannabis use disorder.
  
  
  METHODS
  Controlled family study methods.
  
  
  METHODS
  Out-patient psychiatric clinics and the local community (same geographic area).
  
  
  METHODS
  Two hundred and sixty-two probands with a life-time history of cannabis use disorder, alcohol dependence, anxiety disorders or no history of any disorder, and their first-degree relatives and spouses.
  
  
  METHODS
  Cannabis use disorders and other DSM-III-R disorders in the relatives and spouses using the Schedule for Affective Disorders and Schizophrenia.
  
  
  RESULTS
  Results reveal an elevated risk of life-time history of cannabis use disorders among siblings [odds ratio (OR: 3.6), adult offspring (OR): 6.9], and spouses (OR: 4.4) of probands with cannabis use disorders. There is a latent familial factor underlying cannabis use disorders that was shared partially with alcohol abuse/dependence. Comorbid mood and anxiety disorders aggregated independently from cannabis use disorders in families. Equal elevation in the magnitude of the association among the first-degree adult relatives and spouses of probands with a cannabis use disorder suggests the probable contribution of both environmental and genetic factors.
  
  
  CONCLUSIONS
  These findings support a family-based approach to drug abuse intervention and the importance of future research concerning environmental mediators of familial transmission of drug abuse.
authors.affiliation: Section on Developmental Genetic Epidemiology, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20814-3720, USA. kathleen.merikangas@nih.gov
authors.forename: Kathleen R
authors.initials: KR
authors.lastname: Merikangas
authors.forename: Julan Julia
authors.initials: JJ
authors.lastname: Li
authors.forename: Brooke
authors.initials: B
authors.lastname: Stipelman
authors.forename: Kelly
authors.initials: K
authors.lastname: Yu
authors.forename: Lisa
authors.initials: L
authors.lastname: Fucito
authors.forename: Joel
authors.initials: J
authors.lastname: Swendsen
authors.forename: Heping
authors.initials: H
authors.lastname: Zhang