title: ADHD symptoms, autistic traits, and substance use and misuse in adult Australian twins.
abstract: OBJECTIVE
  Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder frequently co-occur. Several studies show increased risk of substance use disorders in ADHD, yet there is limited information related to how ADHD symptoms, autistic traits, and their combined effects are associated with nicotine, alcohol, and cannabis use and use disorders in the general population.
  
  
  METHODS
  Cross-sectional interview and self-report questionnaire data from 3,080 young adult Australian twins (mean age 31.9 years) were used to assess ADHD symptoms, autistic traits, substance use, and substance use disorders. Substance use disorders-based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria-were assessed in the full sample as well as in those who reported substance use. Logistic regression analyses were used for comparing the associations between ADHD symptoms, autistic traits, substance use, and substance misuse after conduct disorder, sex, age, and zygosity were controlled for.
  
  
  RESULTS
  Greater ADHD symptoms and autistic traits scores were associated with elevated levels of regular smoking; cannabis use; and nicotine, alcohol, and cannabis use disorders, even after conduct disorder was adjusted for. In contrast, for alcohol use, those with high autistic traits scores were less likely to report drinking to intoxication. However, upon initiation, and similar to the findings for nicotine and cannabis, they were at elevated risk for developing alcohol dependence.
  
  
  CONCLUSIONS
  Increased liability to ADHD and elevated autistic traits scores were associated with substance use and misuse, with the exception of alcohol use. Given the social underpinnings of drinking, persons with autistic traits may be less likely to engage in it; however, upon engagement in drinking, their vulnerability to alcohol dependence is elevated.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Duneesha
authors.initials: D
authors.lastname: De Alwis
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Arpana
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Reiersen
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: John N
authors.initials: JN
authors.lastname: Constantino
authors.affiliation: Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
authors.forename: Anjali
authors.initials: A
authors.lastname: Henders
authors.affiliation: Genetic Epidemiology, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
authors.affiliation: Kings College, London, England.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lynskey
mesh_terms: D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000235:genetics / Q000523:psychology; D001315:Australia / Q000453:epidemiology; D001321:Autistic Disorder / Q000453:epidemiology* / Q000235:genetics / Q000523:psychology; D003430:Cross-Sectional Studies; D004200:Diseases in Twins / Q000453:epidemiology* / Q000235:genetics / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000235:genetics / Q000523:psychology; D011795:Surveys and Questionnaires