title: Childhood conduct disorder trajectories, prior risk factors and cannabis use at age 16: birth cohort study.
abstract: OBJECTIVE
  To investigate the prevalence of cannabis use and problem use in boys and girls at age 16 years, and to investigate the role of adversity in early life and of conduct disorder between the ages of 4 and 13 years as risk factors for these outcomes.
  
  
  METHODS
  Birth cohort study.
  
  
  METHODS
  England.
  
  
  METHODS
  A total of 4159 (2393 girls) participants in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort providing information on cannabis use at age 16.
  
  
  METHODS
  Cannabis use and problem cannabis use at age 16 were assessed by postal questionnaire. Material adversity, maternal substance use, maternal mental health and child conduct disorder were all assessed by maternal report.
  
  
  RESULTS
  Cannabis use was more common among girls than boys (21.4% versus 18.3%, P = 0.005). Problem cannabis use was more common in boys than girls (3.6% versus 2.8%, P = 0.007). Early-onset persistent conduct problems were associated strongly with problem cannabis use [odds ratio (OR) = 6.46, 95% confidence interval (CI) = 4.06-10.28]. Residence in subsidized housing (OR = 3.10, 95% CI = 1.95, 4.92); maternal cannabis use (OR 8.84, 95% CI 5.64-13.9) and any maternal smoking in the postnatal period (OR = 2.69, 95% CI = 1.90-3.81) all predicted problem cannabis use. Attributable risks for adolescent problem cannabis use associated with the above factors were 25, 13, 17 and 24%, respectively.
  
  
  CONCLUSIONS
  Maternal smoking and cannabis use, early material disadvantage and early-onset persistent conduct problems are important risk factors for adolescent problem cannabis use. This may have implications for prevention.
authors.affiliation: School of Social and Community Medicine, University of Bristol, Bristol, UK.
authors.forename: Jon
authors.initials: J
authors.lastname: Heron
authors.forename: Edward D
authors.initials: ED
authors.lastname: Barker
authors.forename: Carol
authors.initials: C
authors.lastname: Joinson
authors.forename: Glyn
authors.initials: G
authors.lastname: Lewis
authors.forename: Matthew
authors.initials: M
authors.lastname: Hickman
authors.forename: Marcus
authors.initials: M
authors.lastname: Munafò
authors.forename: John
authors.initials: J
authors.lastname: Macleod
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D019955:Conduct Disorder / Q000453:epidemiology / Q000523:psychology*; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D008016:Life Change Events; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D012959:Socioeconomic Factors
keywords: ALSPAC; Adolescence; cannabis problems; cannabis use; conduct disorder; risk factors; trajectories