title: The association between conduct problems and the initiation and progression of marijuana use during adolescence: a genetic analysis across time.
abstract: The present study used a prospective, longitudinal design to investigate genetic and environmental influences on the association between earlier conduct problems and the initiation and progression of marijuana use during adolescence. Parent- and teacher-reported conduct problems assessed at Time 1 (1996) and self-reported marijuana use assessed at Time 2 (2004) were available for 1088 adolescent twin pairs participating in the Cardiff Study of All Wales and North West of England Twins (CaStANET). Using a novel approach to the modeling of initiation and progression dimensions in substance use, findings suggested that the initiation of marijuana use in adolescence was influenced by genetic, common and unique environmental factors. The progression (or frequency) of marijuana use was influenced by genetic and unique environmental factors. Findings for conduct problems indicated that while the presence or absence of conduct problems was largely heritable, the relative severity of conduct problems appeared to be more strongly environmentally influenced. Multivariate model fitting indicated that conduct problems in childhood and early adolescence made a small but significant contribution to the risk for marijuana use 8 years later.
authors.affiliation: Department of Psychological Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK. Sheltonkh1@cardiff.ac.uk
authors.forename: Katherine
authors.initials: K
authors.lastname: Shelton
authors.forename: Kate
authors.initials: K
authors.lastname: Lifford
authors.forename: Tom
authors.initials: T
authors.lastname: Fowler
authors.forename: Frances
authors.initials: F
authors.lastname: Rice
authors.forename: Mike
authors.initials: M
authors.lastname: Neale
authors.forename: Gordon
authors.initials: G
authors.lastname: Harold
authors.forename: Anita
authors.initials: A
authors.lastname: Thapar
authors.forename: Marianne
authors.initials: M
authors.lastname: van den Bree
mesh_terms: D000293:Adolescent; D000328:Adult; D019955:Conduct Disorder / Q000150:complications / Q000235:genetics*; D018450:Disease Progression; D005178:Faculty; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000150:complications*; D008957:Models, Genetic; D010290:Parents; D000297:Psychology, Adolescent; D012919:Social Behavior; D011795:Surveys and Questionnaires