Pharmacotherapy patterns in the treatment of bipolar disorder.

Objectives: To assess medication use patterns of patients with bipolar disorder, and, through multivariate analysis, to elucidate the role of selected demographic and clinical factors on medication choice and use patterns.

Methods: Patients were privately insured individuals aged 18-64, continuously enrolled in a health plan for 15 months or longer during the years 1994-1998, and either diagnosed with bipolar disorder or prescribed lithium or valproate at least 90 days after the start of the study period. Medical and pharmacy claims data were used to analyze medication therapy over a 12-month period.

Results: First-generation antipsychotics were used by 16.4% of patients and second-generation agents by 12.4%. Patients starting on antipsychotics tended to stay with them for 12 months or longer, while patients starting on anticonvulsants or antidepressants were more likely to stop therapy or to switch to another medication class. Patients treated with olanzapine appeared to have more psychiatric comorbidities and more psychiatric hospitalizations than users of first-generation agents.

Conclusions: Although mood stabilizers and anticonvulsant agents are widely used to treat bipolar disorder, antipsychotic agents are also present in the treatment regimens of bipolar patients. Demographic and clinical factors were significant predictors of the choice of initial medication therapy and subsequent use patterns. In particular, patient gender and the number of psychiatric and physical comorbidities were significantly related to the course of medication therapy.