A study has shown that negative mood-related drinking can make people vulnerable to developing both Major depression (MD) and alcohol dependence (AD).
"Although the frequent co-occurrence of AD and MD is widely recognized, the association between the disorders works differently for different people. 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," said Kelly Young-Wolff, whose master's thesis provided the stimulus for the study.
Victor Hesselbrock, professor of psychiatry at the University of Connecticut School of Medicine, said that the link could also differ by gender.
"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," Hesselbrock said.
Young-Wolff added: "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. 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."
The new findings are based on an examination of 5,181 individuals aged 30 and older (2,928 males and 2253 females), drawn from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, a longitudinal study of psychopathology in two samples of adult twins.
The researchers have revealed that the subjects completed a clinical interview which assessed lifetime MD, AD, and mood-related drinking motives.
"Our study suggests that the familial factors that underlie mood-related drinking motives are the same factors that contribute to the overlapping familial risk for MD and AD. The results are consistent with an indirect role for mood-related drinking motives in risk for depression and AD, and suggest that individuals with strong mood-related drinking motives may be vulnerable to developing both MD and AD," said Young-Wolff.
Hesselbrock added: "In short, the findings indicate that the drinking motives for both males and females who are well into the period of risk for both AD and for major depressive disorder are similar.
However, it should be noted that the findings do not address motives regarding the initiation of drinking behaviour in adolescence; the findings apply only to the subjects' current drinking behaviour. Since this was not a longitudinal study that began in adolescence, it cannot be assumed that these subjects' motives for beginning to drink when they were teenagers were to cope with feelings of depression."
Carol A. Prescott, professor of psychology at the University of Southern California, as well as corresponding author for the study, said: "We might remember that there are many people with high mood-related drinking motives who do not have a history of MD or AD. We would argue that the occasional use of alcohol to relax or unwind is not necessarily a bad idea.
What should be avoided is heavy drinking as a regular coping strategy, since this can lead to other problems and is often a means of avoiding dealing with the issues that are contributing to the negative emotions."
The researchers are of the opinion that their findings may help doctors identify individuals at risk for both MD and AD, with a focus on examining motives for drinking, as well as finding alternative strategies for coping with negative mood states.
Hesselbrock said: "I think it is important that family members understand that there is a real link between drinking and depression. While the family member who is drinking may believe that they are doing so to cope with and relieve their symptoms of depression -and there is some pharmacological basis for this - they probably do not realize that their drinking will only prolong and exacerbate the negative feelings.
For the person without AD, reducing/stopping drinking will help reduce the negative effect/depression. For the person with MD, stopping drinking will help reduce depression symptoms but not totally relieve the depression. It is a complex picture."
The study, to be published in the August issue of Alcoholism: Clinical and Experimental Research, is currently available at Early View.