PITTSBURGH (AP) -- A drug used to control seizures can help people with bipolar disorder and alcoholism stop or reduce drinking, University of Pittsburgh Medical Center researchers reported.

The drug, valproate, is already used to treat bipolar disorder, also known as manic depression, which is marked by episodes of depression and mania.

More than 2 million adults, or 1 percent of the adult population, have bipolar disorder, according to the National Institutes of Mental Health, which funded the study along with the National Institute of Alcohol Abuse and Alcoholism.

Many people with bipolar disorder also abuse alcohol or other drugs.

"Having the combination (bipolar disorder and alcoholism) really complicates the treatment for both of them," said Dr. Ihsan Salloum, the study's lead author and an associate professor of psychiatry at the University of Pittsburgh School of Medicine.

People with bipolar disorder who drink may not stick with their bipolar medication and drinking can complicate it, leading to both increased episodes and increased severity, Salloum said. That can lead to increased hospitalizations and use of costly psychiatric services.

Also, people with bipolar disorder and alcoholism are more likely to commit suicide, he said.

The study, which Salloum said is the first to examine both disorders and how to treat them together, appears in the January edition of Archives of General Psychiatry, published Monday.

Researchers followed 54 patients diagnosed with both disorders for six months. Patients were given their standard treatment, usually a combination of lithium (a common bipolar disorder treatment) and counseling plus valproate or a placebo.

Of those taking valproate, 44 percent reported heavy drinking days -- defined as five or more drinks daily for men and four or more for women -- compared with 68 percent in the placebo group. And the valproate group had about half as many drinks on heavy drinking days than those in the placebo group.

The study also found that those taking valproate were able to stay away from heavy alcohol use for about a month longer than the placebo group. It also found that the valproate group had fewer heavy drinking days than the placebo group.

Some doctors prescribing valproate to treat bipolar patients who are also alcoholics have noticed its effect on drinking and Salloum's findings back that up, said Dr. Kathleen Brady, a Medical University of South Carolina psychiatry professor who has studied valproate and who peer-reviewed the study.

"I think it was a really well-done study and I think the findings are important," she said. "This is going to help people who treat bipolar disorders with alcohol dependency."

Brady said the results were modest, but "clearly demonstrated that valproate added to lithium had better outcomes" than lithium alone.

Salloum acknowledged the relatively small study size, adding that it can be difficult to recruit and retain such patients. He said he hopes others will replicate the study.

Dr. Mark A. Frye, an associate professor of psychiatry at UCLA and director of its bipolar disorder research program, said he was familiar with Salloum's study, but didn't review it. He also called the findings important, saying that studies routinely exclude one disorder or the other.

As for the small size, he said studies that are the first of their kind are important because they establish findings, which can then be further evaluated.

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