- BACKGROUND: Primary care providers are aware of the importance of identifying depression and anxiety in their patients. The diagnosis of posttraumatic stress disorder (PTSD), however, is less of a priority. METHODS: Primary care physicians and nurse practitioners in an outpatient facility of a large health maintenance organization administered a psychiatric screening questionnaire to patients whom they suspected had depression or anxiety. Patients with positive results were referred for immediate consultation with a clinical psychologist. RESULTS: One hundred fourteen (38.6%) of the 296 patients referred for consultation met Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) diagnostic criteria for PTSD. The most frequent traumas associated with PTSD were adult domestic violence and childhood abuse. Patients with a diagnosis of PTSD were frequent users of medical services in the 12 months before diagnosis. The majority of patients sought treatment in primary care settings, not mental health settings. CONCLUSIONS: Patients with PTSD often visit outpatient primary care settings. Medical providers may identify symptoms of depression or anxiety but may not recognize PTSD because of the high degree of overlap between these conditions, and the lack of familiarity with PTSD diagnostic criteria. We provide screening questions that may help physicians detect PTSD in their practices.