title: Intra- and extra-familial influences on alcohol and drug misuse: a twin study of gene-environment correlation.
abstract: OBJECTIVE
  Genotype-environment correlation refers to the extent to which individuals are exposed to environments as a function of their genetic propensities. These correlations are important in the study of psychopathology because they identify environments that may maintain the expression of underlying genetic liabilities for a disorder. The present study examined the correlation between genetic liabilities for alcohol and drug misuse with perceptions of the social environments of the family of origin and the classroom.
  
  
  METHODS
  Postal survey data were collected from monozygotic and dizygotic twin pairs.
  
  
  METHODS
  Twin pairs were recruited from Vancouver, British Columbia, Canada using newspaper advertisements and media stories.
  
  
  METHODS
  Eighty-five monozygotic and 77 dizygotic twin pairs were recruited from the general population.
  
  
  METHODS
  Twin pairs completed self-report measures of alcohol and drug misuse contained in the Dimensional Assessment of Personality Pathology, the Family Environment Scale, the Classroom Environment Scale, and the Traumatic Events Questionnaire.
  
  
  RESULTS
  Genetically indexed alcohol and drug misuse scores were regressed on the environmentally indexed FES and CES scales. Genetic liabilities for alcohol and drug misuse were associated with decreased perceived family moral-religious emphases, family cohesion and classroom task orientation and increased perceptions of classroom order and organization (strictness).
  
  
  CONCLUSIONS
  Genotype-environment correlations, in particular, moral-religious emphases in the home, appear to be important in the development of substance misuse.
authors.affiliation: Division of Behavioural Science, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada. kjang@unixg.ubc.ca
authors.forename: K L
authors.initials: KL
authors.lastname: Jang
authors.forename: P A
authors.initials: PA
authors.lastname: Vernon
authors.forename: W J
authors.initials: WJ
authors.lastname: Livesley
authors.forename: M B
authors.initials: MB
authors.lastname: Stein
authors.forename: H
authors.initials: H
authors.lastname: Wolf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000235:genetics / Q000523:psychology; D001955:British Columbia; D005195:Family Relations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D012307:Risk Factors; D012931:Social Environment; D019966:Substance-Related Disorders / Q000235:genetics* / Q000523:psychology; D011795:Surveys and Questionnaires; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic