BACKGROUND Hallucinations and delusions (H+D) are common in dementia, but screening for these symptoms-especially in busy clinical practices-is challenging. METHODS Six subject matter experts developed the DRP3™ screen, a novel valid tool to detect H+D in dementia, assessed its content validity through alignment with DRP reference assessments (Scale for the Assessment of Positive Symptoms-Hallucinations + Delusions, Neuropsychiatric Inventory-Questionnaire, International Psychogeriatric Association Criteria), and retrospectively investigated its ability to detect H+D in HARMONY trial (NCT03325556) enrollees. RESULTS All items from three reference assessments demonstrated significant agreement with the DRP3 screen among raters (P < .0001). Retrospectively applying the DRP3 screen to HARMONY identified all (N = 392) trial enrollees. CONCLUSIONS The DRP3 screen, comprising three yes/no questions, is a content-valid tool for detecting H+D in dementia that aligned with current reference assessments and successfully identified trial participants when retrospectively applied to a completed trial. Within busy practice constraints, the DRP3 screen provides a brief tool for sensitive detection of H+D in patients with dementia.