Psychiatric complications of long-term interferon alfa therapy.

Ten (17%) of 58 patients with chronic viral hepatitis treated with a four- to 12-month course of recombinant human interferon alfa developed psychiatric side effects. The psychiatric side effects fell into three categories: an organic personality syndrome characterized by irritability and short temper; an organic affective syndrome marked by extreme emotional lability, depression, and tearfulness; and a delirium marked by clouding of consciousness, agitation, paranoia, and suicidal potential. These psychiatric side effects appeared after one to three months of therapy, usually improved within three to four days of decreasing the dose of interferon alfa, and invariably resolved once therapy was stopped. The organic personality and affective syndromes tended to occur in patients who received the highest dose of interferon alfa, who had relatively mild hepatitis, and who lost weight during interferon treatment. Delirium tended to occur in patients with severe hepatitis who had previous evidence of organic brain injury or dysfunction or previous drug and alcohol abuse. Failure to recognize these side effects quickly and to treat them with supportive therapy and modification of the dose of interferon alfa could result in limitation of therapy and serious personal and interpersonal consequences.