PORTLAND, Oregon (VA Research Communications Service) -- Portland Veterans Affairs Medical Center researchers and their colleagues have found that many people develop major depression while taking interferon, the most effective drug against the life-threatening liver disease hepatitis C.

The majority of patients developed at least some symptoms of depression and 33 percent met criteria for major depression, said study leader Peter Hauser, M.D., Chief of Psychiatry and Associate Director of the Northwest Hepatitis C Resource Center at the Portland VA Medical Center, and Professor of Psychiatry at Oregon Health & Science University.

"The good news is that in most cases we could successfully treat the depression," Hauser said, "and patients could continue their interferon therapy."

Studies have noted interferon-associated depression, but the incidence remained poorly understood, Hauser said. "Also, the usual and customary practice has been to take patients off interferon if they become depressed. We're saying there's an alternative."

Hauser and his colleagues report on their findings in the November issue of the journal Molecular Psychiatry. The researchers studied 39 patients infected with the hepatitis C virus (HCV) and taking interferon therapy.

Patients were monitored weekly with the Beck Depression Inventory, a commonly used assessment tool for depression, and those who became depressed were treated with the antidepressant citalopram. Thirteen of the patients (33 percent) developed interferon-induced major depression, with the average onset about 12 weeks after starting therapy. When treated with citalopram, however, 11 of these patients (84 percent) improved significantly and could continue their interferon therapy.

No differences were noted in age, gender, past history of major depression, or substance abuse between those who became depressed and those who did not. For unknown reasons, Hauser noted, there were significantly fewer African American patients in the depressed group.

An estimated 4 million Americans harbor HCV. Because symptoms of liver disease may take decades to develop, however, exact numbers are unknown and doctors consider hepatitis C a "hidden epidemic." HCV often was spread by transfusions before a test for the virus became available in 1992, allowing blood supply screening.

Although the organism can be spread by needle sharing among IV drug users, the source of infection in many cases is unknown. Liver failure caused by HCV is the leading reason for liver transplants, and chronic hepatitis C has been linked to a form of liver cancer.

No vaccine is available, and only about 15 percent of people infected with the virus are able to fight it off on their own and never develop chronic hepatitis C. Interferon response rates depend on the HCV genetic type, Hauser said, ranging from about 50 percent to as many as 80 percent of infected patients with the most recent combinations therapies.

"So it's very important to keep people on treatment if at all possible," he emphasized.

The research team will soon begin a new study to determine whether antidepressant treatment early in interferon therapy can prevent the development of depression.

In addition to Hauser, co-authors of the Molecular Psychiatry paper include Ashlee J. Thornton and Rachel L. Schultz of the Portland VA Medical Center/OHSU; Jaswinder Khosla, Havinder Aurora, Jacqueline Laurin, Mitchel A. Kling, Jo Ann Hill, Mangla Gulati and Charles D. Howell of the Baltimore VA Medical Center/University of Maryland School of Medicine; and Alan D. Valentine and Christina A. Meyers of the MD Anderson Cancer Center in Houston, Texas.