Negative mood-related drinking may mean vulnerability for major depression and alcohol dependence

* Major depression (MD) and alcohol dependence (AD) are strongly connected to one another.
* New research looks at how mood-related drinking may explain the overlapping familial risk for MD and AD.
* Drinking related to mood that is based on negative feelings accounted for the majority of the overlapping risk for both MD and AD that is due to genetic and familial environmental factors.

Major depression (MD) and alcohol dependence (AD) co-occur in individuals and within families at higher rates than expected by chance. This study looked at how mood-related drinking motives may explain the overlapping familial risk for MD and AD. Findings suggest that individuals with strong mood-related drinking motives, especially those based on negative feelings, may be vulnerable to developing both MD and AD.

Results will be published in the August issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"Although the frequent co-occurrence of AD and MD is widely recognized, the association between the disorders works differently for different people," explained Kelly Young-Wolff, whose master's thesis provided the stimulus for the study. "There are likely multiple mechanisms that result in the disorders co-occurring, for example, having MD increases the risk to develop AD, having AD increases the risk to develop MD; and causal factors – such as genetic risk or social circumstances – also contribute to developing both disorders."

The association can also differ by gender, added Victor Hesselbrock, professor of psychiatry at the University of Connecticut School of Medicine.

"Studies of both clinical and community samples have found that primary depression – depression occurs first, followed by alcoholism – is more typical in females while primary alcoholism – alcoholism followed by depression – is more common among males. Furthermore, while most persons affected with alcoholism do report a lifetime history of significant depressive symptoms, the reverse is not true. Most people with depression do not report long periods of heavy drinking nor do they report significant numbers of lifetime AD symptoms."

"Previous research had shown that individuals with higher than average scores on mood-related drinking scales are at increased risk to develop heavy drinking and AD," said Young-Wolff. "There is also evidence for familial risk factors, such as shared social and environmental or genetic factors, that contribute to overlapping risk for MD and AD, and for AD and mood-related drinking motives. Yet no study had examined whether mood-related drinking motives explain the overlapping familial risk for MD and AD."

Researchers examined 5,181 individuals (2,928 males, 2253 females), aged 30 and older, drawn from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, a longitudinal study of psychopathology in two samples of adult twins. Participants completed a clinical interview which assessed lifetime MD, AD, and mood-related drinking motives.