title: Adolescent precursors of cannabis dependence: findings from the Victorian Adolescent Health Cohort Study.
abstract: BACKGROUND
  Dependence increases the likelihood of adverse consequences of cannabis use, but its aetiology is poorly understood.
  
  
  OBJECTIVE
  To examine adolescent precursors of young-adult cannabis dependence.
  
  
  METHODS
  Putative risk factors were measured in a representative sample (n=2032) of secondary students in the State of Victoria, Australia, six times between 1992 and 1995. Cannabis dependence was assessed in 1998, at age 20-21 years.
  
  
  RESULTS
  Of 1601 young adults, 115 met criteria for cannabis dependence. Male gender (OR=2.6, P < 0.01), regular cannabis use (weekly: OR=4.9; daily: OR=4.6, P=0.02), persistent antisocial behaviour (linear effect P=0.03) and persistent cigarette smoking (linear effect P=0.02) independently predicted cannabis dependence. Neither smoking severity (P=0.83) nor persistent psychiatric morbidity (linear effect P=0.26) independently predicted dependence. Regular cannabis use increased risk only in the absence of persistent problematic alcohol use.
  
  
  CONCLUSIONS
  Weekly cannabis use marks a threshold for increased risk of later dependence, with selection of cannabis in preference to alcohol possibly indicating an early addiction process.
authors.affiliation: Murdoch Children's Research Institute, Parkville, Victoria, Australia. carolyn.coffey@rch.org.au
authors.forename: Carolyn
authors.initials: C
authors.lastname: Coffey
authors.forename: John B
authors.initials: JB
authors.lastname: Carlin
authors.forename: Michael
authors.initials: M
authors.lastname: Lynskey
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: George C
authors.initials: GC
authors.lastname: Patton
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology; D000328:Adult; D000428:Alcohol Drinking / Q000523:psychology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology / Q000523:psychology*; D000297:Psychology, Adolescent; D012044:Regression Analysis; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000523:psychology; D012920:Social Behavior Disorders / Q000523:psychology; D014739:Victoria / Q000453:epidemiology