OBJECTIVE: Assess trends in pharmacologic treatment for patients with bipolar disorder. METHODS: A large claims database of insured individuals from 10/1992 to 9/2002 was analyzed to identify patients diagnosed with bipolar disorder (ICD9-CM: 296.4x-296.8x). Treatment regimens were examined for six-classes of psychotropics (antidepressants, mood-stabilizers, atypical and typical antipsychotics, anxiolytics and hypnotics). RESULTS: Of 13,407 patients, the percent untreated remained stable around 10% over the 10-year period. Among treated patients, about 65% received mood stabilizers and/or antidepressants. The two agents most frequently used were valproate (39.7%) and olanzapine (24.2%) in 2002. Overall, mood stabilizers increased slightly from 59.5% to 64.2%, and atypical antipsychotics increased from 4.5% to 45.1% usage. Antidepressants and anxiolytics remained stable at around 65% and 50% respectively, although the products chosen shifted with new market introductions. Typical antipsychotics decreased from 34.5% to12.4%, and hypnotics decreased from 13.2% to around 7% usage. CONCLUSIONS: Although about two-thirds of patients with bipolar illness receive mood stabilizers, there continues to be opportunity for improvement in pharmacotherapy. It is also important to understand outcomes associated with changing treatment patterns for bipolar patients.