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, duringwhich time Medi-Cal maintained prior authorization restrictions on second generation antipsychoticdrugs. Prescription records were used to identify 3 patterns of antipsychotic drug use: no drug therapyfor over 1 year; delayed onset of antipsychotic drug therapy; and switches in antipsychotic drugswithin 1 year. Multiple logistic regression models were used to identify factors affecting these antipsychoticdrug 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 antipsychoticmedication for periods lasting up to 1 year. Over 24% of treated patients delayed the use of antipsychoticmedications at least 30 days. For those patients who did not delay their use of antipsychoticmedications, over 47% switched or augmented their initial antipsychotic medication during the firsttreatment year. Only 11.6% of treated patients achieved 1 year of uninterrupted antipsychotic drugtherapy. 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 ofpatients with schizophrenia.