Influence of an inconsistent appearance of antipsychotics on drug adherence in patients with schizophrenia

In this study, we aimed to determine whether an inconsistent appearance of antipsychotic drugs dispensed was associated with poorer adherence in patients with schizophrenia. To conduct this study, we linked information from different administrative healthcare databases from the Basque Country. Patients with a medication possession ratio (<80%) were considered to be nonadherent. More than a quarter of the study population (26.9%, 1294/4810) was nonadherent to antipsychotics. Different brands of the same antipsychotic were dispensed to 8.5% of the patients. Inconsistent appearance was not associated with nonadherence to antipsychotics. Lower adherence to antipsychotics was associated with several other factors: age ≥65 or <30 years, prescription of typical antipsychotics or of long-acting injectable compounds, and nonadherence to antihypertensive and lipid-lowering drugs. Contrary to our expectations, we did not find a significant association between inconsistent appearance of prescribed antipsychotics and poorer adherence. The percentage of patients who were dispensed different brands of the same antipsychotics was also lower than expected.