Use patterns for antipsychotic medications in medicaid patients with schizophrenia.

OBJECTIVE: We investigated the use patterns for antipsychotic medications generated by Medicaid patients with schizophrenia.

METHOD: Paid claims data from the California Medicaid program (Medi-Cal) were used to identify 2655 patients with schizophrenia. Data from 1987-1996 were used, during which time Medi-Cal maintained prior authorization restrictions on second generation antipsychotic drugs. Prescription records were used to identify 3 patterns of antipsychotic drug use: no drug therapy for over 1 year; delayed onset of antipsychotic drug therapy; and switches in antipsychotic drugs within 1 year. Multiple logistic regression models were used to identify factors affecting these antipsychotic drug use patterns.

RESULTS: Conventional antipsychotic medications account for over 98% of all patient treatment episodes. Over 24% of patients with schizophrenia do not use any antipsychotic medication for periods lasting up to 1 year. Over 24% of treated patients delayed the use of antipsychotic medications at least 30 days. For those patients who did not delay their use of antipsychotic medications, over 47% switched or augmented their initial antipsychotic medication during the first treatment year. Only 11.6% of treated patients achieved 1 year of uninterrupted antipsychotic drug therapy. The mean duration of uninterrupted therapy was 142 days.

DISCUSSION: Antipsychotic drug use patterns suggest that conventional antipsychotic medications do not meet the therapeutic needs of patients with schizophrenia.