This study examined the impact of Medicare Part D cost-sharing on antipsychotic drug spending, out-of-pocket costs, and adherence among Medicare Advantage beneficiaries with schizophrenia. The results showed that entering the coverage gap was associated with increased out-of-pocket costs and decreased adherence for non-low income subsidy beneficiaries, while low income subsidy beneficiaries were protected from these impacts. The decrease in adherence varied between integrated and non-integrated Medicare Advantage plans. This study provides initial evidence on the effect of Medicare drug benefits on access to and quality of care for antipsychotic medications.