title: Externalizing disorders and substance use: empirically derived subtypes in a population-based sample of adults.
abstract: OBJECTIVE
  Attention-deficit/hyperactivity disorder (ADHD), conduct disorder (CD), and oppositional defiant disorder (ODD) are common externalizing disorders of childhood. The common effects of these disorders on substance abuse need further investigation. The current study investigated the joint clusters of childhood/adolescence ADHD, CD, and ODD, and their influence on substance abuse/dependence in a population-based sample of adults.
  
  
  METHODS
  The data were drawn from the PsyCoLaus study (n = 3,720) conducted in Lausanne, Switzerland. The population-based sample included 238 subjects meeting criteria for ADHD/ODD/CD diagnoses before the age of 15. Latent class analyses (LCA) were performed to derive comorbidity subtypes, which were subsequently characterized with respect to psychosocial correlates and substance use.
  
  
  RESULTS
  The best fit in LCAs was achieved with three latent classes: an ADHD subtype (35.7 %); an externalizing multimorbid subtype (33.6 %) involving ODD, ADHD, and CD; and a third subtype with CD (30.7 %). The CD subtype showed the highest association with substance use. Apart from this, the externalizing multimorbid subtype was also significantly linked to substance use. The ADHD subtype had only elevated frequencies for alcohol dependence in comparison with subjects that had no history of ADHD, ODD, and CD during childhood or adolescence. Finally, important interactions between subtypes and sex were observed with regard to substance use.
  
  
  CONCLUSIONS
  This study provides evidence showing that subtyping the externalizing disorders, ADHD, ODD and CD, along their comorbidity patterns leads to important differences regarding substance use. This could have implications for the etiology, prevention, and treatment of substance use disorders.
authors.affiliation: Department of Psychiatry, Psychotherapy and Psychosomatics, Zurich University Hospital of Psychiatry, PO Box 1930, CH-8021, Zurich, Switzerland, stephanie.rodgers@dgsp.uzh.ch.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rodgers
authors.forename: Mario
authors.initials: M
authors.lastname: Müller
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
authors.forename: Enrique
authors.initials: E
authors.lastname: Castelao
authors.forename: Martin
authors.initials: M
authors.lastname: Preisig
authors.forename: Vladeta
authors.initials: V
authors.lastname: Ajdacic-Gross
mesh_terms: D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000453:epidemiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology*; D015897:Comorbidity; D019955:Conduct Disorder / Q000453:epidemiology*; D019263:Dysthymic Disorder / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D017678:Sex Distribution; D019966:Substance-Related Disorders / Q000453:epidemiology*; D013557:Switzerland / Q000453:epidemiology