For problem drinkers, bouts of depressive symptoms are often the direct result of their heavy alcohol intake, according to a study in the March issue of the Journal of Studies on Alcohol and Drugs.
Experts have long known that heavy drinking can spur temporary episodes of depression—what's known as "substance-induced depression." However, this information is not always apparent to busy clinicians, and the new findings strengthen the evidence that the phenomenon exists as well as how common and clinically important it is.
"I don't know that the average person realizes that heavy drinking can induce mood problems," said lead researcher Marc A. Schuckit, M.D., of the University of California, San Diego School of Medicine.
What's more, not every doctor might be aware of it, either. But it's important that he or she pay close attention to this problem, Schuckit said, because depression caused by heavy drinking has a different prognosis and is treated much differently from major depressive episodes that are not seen in the context of heavy drinking. Although the symptoms of independent and substance-induced depressions can be identical, if the sadness develops in the context of heavy drinking, the symptoms are likely to lift within several weeks to a month of abstinence and rarely require antidepressants to go away.
The findings come from a 30-year study of nearly 400 men who were 18 years old at the outset. About half were at increased risk for drinking problems because their fathers were alcoholics. Over three decades, about 41 percent of the men with alcoholic fathers developed alcohol abuse or dependence, and nearly 20 percent suffered at least one bout of major depression.
For men with alcohol problems, though, almost one third of those major depressive episodes were seen only while they were drinking heavily.
It's important for doctors to consider alcohol use disorders as a possible cause of patients' depression symptoms, Schuckit said—rather than simply "reaching for the prescription pad" and recommending an antidepressant.
If alcohol is the cause, "the depression is very likely to disappear with abstinence," Schuckit said.
Many people think that some individuals drink heavily because they are depressed, and that is the case for some. But Schuckit's team actually found no evidence that people with a history of major depression were at increased risk for developing alcohol problems in the future.
"If you're an alcoholic, you're going to have a lot of mood problems," Schuckit said. "And you may be tempted to say, 'Well, I drink a lot because I'm depressed.' You may be right, but it's even more likely that you're depressed because you drink heavily."
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Journal of Studies on Alcohol and Drugs, 74(2), 271, 2013