title: Role of self-medication in the development of comorbid anxiety and substance use disorders: a longitudinal investigation.
abstract: BACKGROUND
  Self-medication of anxiety symptoms with alcohol, other drugs, or both has been a plausible mechanism for the co-occurrence of anxiety disorders and substance use disorders. However, owing to the cross-sectional nature of previous studies, it has remained unknown whether self-medication of anxiety symptoms is a risk factor for the development of incident substance use disorder or is a correlate of substance use.
  
  
  OBJECTIVE
  To examine whether self-medication confers risk of comorbidity.
  
  
  METHODS
  A longitudinal, nationally representative survey was conducted by the National Institute on Alcohol Abuse and Alcoholism. The National Epidemiologic Survey on Alcohol and Related Conditions assessed DSM-IV psychiatric disorders, self-medication, and sociodemographic variables at 2 time points.
  
  
  METHODS
  The United States.
  
  
  METHODS
  A total of 34 653 US adults completed both waves of the survey. Wave 1 was conducted in 2001-2002, and wave 2 interviews occurred 3 years later (2004-2005).
  
  
  METHODS
  Incident substance use disorders in participants with baseline anxiety disorders and incident anxiety disorders in those with baseline substance use disorders.
  
  
  RESULTS
  Logistic regression analyses revealed that self-medication conferred a heightened risk of new-onset substance use disorders in those with baseline anxiety disorders (adjusted odds ratios [AORs], 2.50-4.99 [P < .01]). Self-medication was associated with an increased risk of social phobia (AOR in baseline alcohol use disorders, 2.13 [P = .004]; AOR in baseline drug use disorders, 3.17 [P = .001]).
  
  
  CONCLUSIONS
  Self-medication in anxiety disorders confers substantial risk of incident substance use disorders. Conversely, self-medication in substance use disorders is associated with incident social phobia. These results not only clarify several pathways that may lead to the development of comorbidity but also indicate at-risk populations and suggest potential points of intervention in the treatment of comorbidity.
authors.affiliation: Department of Psychiatry, University of Manitoba, 771 Bannatyne Ave, Winnipeg, MB, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Robinson
authors.forename: Jitender
authors.initials: J
authors.lastname: Sareen
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cox
authors.forename: James M
authors.initials: JM
authors.lastname: Bolton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001007:Anxiety / Q000150:complications / Q000209:etiology*; D017831:Diagnosis, Dual (Psychiatry) / Q000523:psychology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012651:Self Medication / Q000009:adverse effects*; D019966:Substance-Related Disorders / Q000150:complications / Q000209:etiology*