Antipsychotic medications are commonly prescribed to older adults with dementia to control behavioral symptoms despite research showing this practice to be harmful. In this randomized control study, primary care providers (PCPs) with high rates of quetiapine (an antipsychotic) prescribing were sent either a neutral letter (control) or a warning letter (intervention) from Centers for Medicare & Medicaid Services (CMS). The health outcomes of the PCPs' patients were analyzed at regular intervals. There were no statistically significant differences in health outcomes between the intervention and control groups. The largest decreases in prescribing were seen in lower-rated nursing homes without an increase in associated adverse events.