Bipolar disorder is recurrent and requires maintenance therapy. Lithium is standard for preventing relapse but is ineffective for many patients, and few other drugs are established as maintenance treatments. Several atypical antipsychotic drugs have shown success as short-term interventions for acute mania, and now Tohen et al. (p. 247) report a large 48-week double-blind olanzapine trial for maintenance treatment of bipolar disorder. Among patients in remission after short-term olanzapine use, the median time to relapse was 174 days for patients who continued taking olanzapine and 22 days for those switched to placebo (see F1). The rates of study completion were low, however: 21.3% for olanzapine and 6.6% for placebo. Olanzapine was associated with substantial weight gain, abnormal QTc interval, and increased prolactin level. Despite these drawbacks, olanzapine’s ability to prolong remission increases the long-term therapeutic possibilities for bipolar disorder.