PMH9Month-To-Month Adherence with Antipsychotic Pharmacotherapy: A Comparison Between Atypical and Typical Antipsychotics

Adherence to antipsychotic therapy is associated with greater likelihood of positive outcomes for schizophrenia treatment. Atypical antipsychotic agents, with broader response profiles and greater tolerability, may increase the probability of compliance with drug therapy relative to typical antipsychotic agents.OBJECTIVE: This study compares month-to-month adherence to pharmacotherapy between atypical and typical antipsychotics in the naturalistic care setting. METHODS: Claims from a large U.S. prescription database were analyzed for 56,682 patients who received at least one antipsychotic prescription between 5/1 and 7/31/1995. A patient's first antipsychotic prescription (the index prescription) during this interval was used to classify the patient from an intent-to-treat perspective as an atypical or typical antipsychotic user. Month-to-month adherence to pharmacotherapy for 32,066 patients who did not receive an antipsychotic prescription during the 12-month period preceding their index prescriptions were tracked over a two-year period following their index prescriptions. Month-to-month adherence on drug therapy was measured as possessing at least 15 days of the same antipsychotic within a 30-day period. RESULTS: Almost all (97%) atypical antipsychotics recipients successfully completed at least one month of compliance on pharmacotherapy, compared to only half (53%) of recipients on typical antipsychotics. At the 6th month, 54% of atypical and 26% of typical antipsychotic recipients were compliant. These percentages declined to 45% and 22% at the 12th month, 40% and 19% at the 18th month, and 11% and 5% at the 24th month for atypical versus typical antipsychotic recipients, respectively. CONCLUSIONS: Measured over a maximum of 24 months, patients on atypical antipsychotics were more likely to adhere on a month-to-month basis with antipsychotic therapy.