Is the association of alcohol use disorders with major depressive disorder a consequence of undiagnosed bipolar-II disorder?
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.
Angst
Jules
J
Zurich University Psychiatric Hospital, Lenggstrasse 31, Mail Box 1931, 8032, Zurich, Switzerland. jangst@bli.unizh.ch
Gamma
Alex
A
Endrass
Jérôme
J
Rössler
Wulf
W
Ajdacic-Gross
Valdeta
V
Eich
Dominique
D
Herrell
Richard
R
Merikangas
Kathleen Ries
KR
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