Validity of electronically monitored medication adherence and conventional adherence measures in schizophrenia

Objective: This study evaluated the validity of prescriber, patient, and research assistant ratings of adherence to prescribed oral antipsychotic medication among outpatients with schizophrenia or schizoaffective disorder in comparison with electronic monitoring. Methods: Adult outpatients with schizophrenia (N= 35) or schizoaffective disorder (N= 26) received adherence assessments via electronically monitored medication vial caps as well as by monthly prescriber, patient, and research assistant report for up to six months. Results: Electronic monitoring detected greater nonadherence rates (57%) than either prescribers (7%) or patients (5%), though the research assistant ratings were 54%. No directional bias was found between electronic monitoring and assignment of adherence by research assistants, although disagreement occurred in 36% of cases. Conclusions: Both patients and prescribers grossly overestimated medication adherence, which may interfere with or reduce the effectiveness of diligent medication management.