OBJECTIVES: To profile antipsychotic use among bipolar disorder patients, including antipsychotic type, duration of use, gaps in therapy, and concurrent mood-stabilizer and antidepressant therapy. METHODS: Bipolar disorder patients with at least two antipsychotic prescriptions filled between January 1, 1999, and December 31, 2001 were extracted from a Medicaid database. Initiation of antipsychotic therapy was indicated by the absence of claims for antipsychotic medication within 90 days prior to the first prescription. Duration of therapy was calculated from the first prescription fill date to the end of 12 months follow-up or discontinuation of antipsychotic therapy. Gaps between refills were defined as the number of days between the depletion date and the fill date. A treatment gap category was calculated for each patient based on the longest continuous gap between refills. Antipsychotic use was considered to be first-line treatment if there were no claims for mood-stabilizers in the 12 months before antipsychotic initiation. Prescription claims in the 12-month follow-up period were examined to classify treatments as antipsychotic alone or combined with mood-stabilizer or antidepressant. RESULTS: Among 832 patients initiated on antipsychotics, 75.4% were initiated on atypicals and 24.6% on typicals. The average duration of therapy was 224.5 (±140.5) days. In total, 58.9% of patients had gaps between refills exceeding 30 days, and 22.7% had at least one gap exceeding 90 days. The average duration of the longest gap was 61.2 (±70.3) days. Antipsychotics were the first-line treatment in 66.8% of patients. During follow-up, 56.3% of patients used antipsychotics alone, 43.8% used combinations of antipsychotics and mood-stabilizers, and 73.7% used antipsychotics with antidepressants. CONCLUSION: Short duration of antipsychotic use and long gaps in therapy indicate poor adherence to therapy in bipolar disorder patients. About two-thirds of patients initiate antipsychotics before mood-stabilizers. Concomitant use of a mood-stabilizer or antidepressant with antipsychotic is highly prevalent.