title: Is the association of alcohol use disorders with major depressive disorder a consequence of undiagnosed bipolar-II disorder?
abstract: BACKGROUND
  There is emerging evidence that there is a spectrum of expression of bipolar disorder. This paper uses the well-established patterns of comorbidity of mood and alcohol use disorder to test the hypothesis that application of an expanded concept of bipolar-II (BP-II) disorder might largely explain the association of alcohol use disorders (AUD) with major depressive disorder (MDD).
  
  
  METHODS
  Data from the Zurich study, a community cohort assessed over 6 waves from ages 20/21 to 40/41, were used to investigate the comorbidity between mood disorders and AUD. Systematic diagnostic criteria were used for alcohol abuse, alcohol dependence, MDD, and BP-II. In addition to DSM criteria, two increasingly broad definitions of BP-II were employed.
  
  
  RESULTS
  There was substantially greater comorbidity for the BP-II compared to major depression and for alcohol dependence compared to alcohol abuse. The broadest concept of BP-II explained two thirds of all cases of comorbidity of AUD with major depressive episodes (MDE). In fact, the broader the definition of BP-II applied, the smaller was the association of AUD with MDD, up to non-significance. In the majority of cases, the onset of bipolar manifestations preceded that of drinking problems by at least 5 years.
  
  
  CONCLUSIONS
  The findings that the comorbidity of mood disorders with AUD was primarily attributable to BP-II rather than MDD and that bipolar symptoms usually preceded alcohol problems may encourage new approaches to prevention and treatment of AUD.
authors.affiliation: Zurich University Psychiatric Hospital, Lenggstrasse 31, Mail Box 1931, 8032, Zurich, Switzerland. jangst@bli.unizh.ch
authors.forename: Jules
authors.initials: J
authors.lastname: Angst
authors.forename: Alex
authors.initials: A
authors.lastname: Gamma
authors.forename: Jérôme
authors.initials: J
authors.lastname: Endrass
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
authors.forename: Valdeta
authors.initials: V
authors.lastname: Ajdacic-Gross
authors.forename: Dominique
authors.initials: D
authors.lastname: Eich
authors.forename: Richard
authors.initials: R
authors.lastname: Herrell
authors.forename: Kathleen Ries
authors.initials: KR
authors.lastname: Merikangas
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D001714:Bipolar Disorder / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D015331:Cohort Studies; D003865:Major Depressive Disorder / Q000150:complications* / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D012727:Sex Characteristics; D013557:Switzerland / Q000453:epidemiology