Two predictors of bipolar relapse identified.
This finding, which is based on a posthoc analysis of data collected from two treatment studies involving 779 patients, suggests that there may be a differential risk of relapse among certain patients with bipolar disorder. Identifying subpopulations that are particularly vulnerable to the disease may aid the management of patients and help in the development of more effective treatment strategies, Dr. Tohen said.
In addition, the finding that patients who rapidly cycle or have a mixed-index episode are more prone to relapse is consistent with the prior observation that these patients are usually less responsive to treatment, added Dr. Tohen, a psychiatrist at McLean Hospital in Belmont, Mass., and at Harvard Medical School in Boston.
The two studies used in this analysis were designed to assess the efficacy of the atypical antipsychotic drug olanzapine for maintenance treatment of patients with bipolar I disorder.
In one study, patients were treated with a combination of olanzapine plus lithium for 6-12 weeks on an open-label basis until remission was achieved. Patients were then randomized to either olanzapine or lithium monotherapy in a double-blind fashion for a maintenance phase of 48 weeks. In the second study, patients were all treated with open-label olanzapine for 6-12 weeks to achieve remission, after which they were randomized to either olanzapine or placebo in a double-blind fashion for 48 weeks of maintenance therapy.
During the maintenance phase, 434 patients were treated with olanzapine at an average dosage of about 12 mg/day; 213 were treated with lithium at an average dosage of about 1,100 mg/day; and 132 received placebo. Both studies were funded by Eli Lilly & Co., which markets olanzapine (Zyprexa). Dr. Tohen is a researcher on the staff of Lilly in Indianapolis.
Fourteen clinical features that were tracked for all patients were tested as predictors of relapse in a case-control analysis. In a multivariate model, two factors emerged as the strongest predictors: a history of a mixed-index episode, and a rapid cycling course. Each of these factors independently boosted a patient's risk of relapse by about 50%. About 24% of the 779 patients in the study had a rapid cycling course, and 19% had a mixed-index episode.
Other factors assessed that were not independent predictors of relapse in the multivariate model included prolonged (more than 3 years) duration of the disorder, onset of major depression at less than 20 years old, and prior mixed episodes or episodes of mania or depression during the year prior to the study.
BY MITCHEL L. ZOLER
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|Title Annotation:||Adult Psychiatry|
|Author:||Zoler, Mitchel L.|
|Publication:||Clinical Psychiatry News|
|Date:||Sep 1, 2004|
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