Use patterns for antipsychotic medications in medicaid patients with schizophrenia

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

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.

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.

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