Much of the evidence about preventable harm in patients with psychiatric illnesses is limited to inpatient psychiatric facilities. This case-control study explores patient-related factors that place patients at an increased risk for patient safety incidents in primary or emergency care. While differences in income, education, and foreign background had some association with preventable harm, researchers found that psychiatric illness nearly doubled the risk of preventable harm among both emergency and primary care patients, with nearly half (46%) of harm attributable to diagnostic errors.