Patients with acute mania who received risperidone with a mood stabilizer responded to treatment more rapidly and achieved significantly greater improvement than individuals who received only a mood stabilizer, according to an article in the July issue of the American Journal of Psychiatry.

Risperidone is currently approved in the United States only for the treatment of schizophrenia. However, the atypical antipsychotic agent is approved in ten countries as adjunctive therapy in the treatment of acute mania, and Phase III trials are underway in the U.S. on its use as monotherapy for acute mania. Approximately 3.4 percent of Americans suffer from bipolar spectrum disorder.

In the current study, a three-week, double-blind, placebo-controlled trial, 156 people hospitalized for mania were randomized to receive one of three agents in addition to a mood stabilizer (either lithium or valproate): risperidone (52 patients), haloperidol (53 patients), or placebo (51 patients).

The primary measure of efficacy was a change in the Young Mania Rating Scale, which is widely used to assess degree of mania. Individuals treated with risperidone had a significantly greater improvement in manic symptoms during their participation in the study than those who received a mood stabilizer plus placebo. Improvement with risperidone and mood stabilizer was similar to that seen in patients who received haloperidol and mood stabilizer.

At the end of the study, significant between-group differences were seen with the Clinical Global Impression scale between patients on placebo as adjunctive therapy and patients on risperidone as adjunctive therapy. Ratings of "much improved" or "very much improved" were reported in 53 percent of patients taking risperidone and a mood stabilizer versus 30 percent of patients receiving placebo and a mood stabilizer. As with the mania rating scale, results were comparable for both groups receiving an antipsychotic agents plus mood stabilizer.

Significant reduction in symptoms was seen early in the course of treatment among the patients in the risperidone group: Improvement was seen as early as week one. In addition, treatment with risperidone was well tolerated overall. Rates of extrapyramidal symptoms were 28 percent for haloperidol, 13 percent for risperidone, and 4 percent for mood stabilizers used alone. Severity of extrapyramidal symptoms at endpoint was similar in the placebo plus mood stabilizer and risperidone plus mood stabilizer groups.

More patients in the risperidone group (65 percent) completed the double-blind phase of the study than did the counterparts who received a mood stabilizer alone (51 percent) or adjunctive treatment with haloperidol (47 percent).

"This study provides support for the evolving use of psychotropics like risperidone to control the manic symptoms of bipolar disorder," says Gary Sachs, M.D., lead author of the study.