Validation of a brief screen for Post-Traumatic Stress Disorder with substance use disorder patients Rachel Kimerling a, * , Jodie A. Trafton b , Brian Nguyen b a National Center for PTSD, VA Palo Alto Health Care System, 795 Willow Road (PTSD-334), Menlo Park, CA 94025, USA b Program Evaluation and Resource Center, VA Palo Alto Health Care System and Stanford University School of Medicine, 795 Willow Road (152-MPD), Menlo Park, CA 94025, USA Abstract To evaluate a 4-item screen for Post-Traumatic Stress Disorder (PTSD) for use with patients diagnosed with substance use disorders, 97 patients were recruited from substance use disorder treatment clinics at a large medical center. Participants completed the self-administered 4-item PTSD screen. Psychologists interviewed patients using the Clinician Administered PTSD Scale (CAPS). Sensitivity and specificity were calculated using the CAPS as the criterion for PTSD. Results were compared to chart diagnoses. The prevalence of PTSD was 33%. The screen identified 91% of PTSD cases, where only 25% of PTSD cases were diagnosed in the medical chart. The screen demonstrated good test–retest reliability (r = .80) and yielded a sensitivity of .91 and specificity of .80 using a cut score of 3. Likelihood ratios indicate that the screen has good ability to detect PTSD in this population, and that patients with positive screens that do not meet criteria for PTSD are likely to report significant subthreshold symptoms. Screening for PTSD in SUD treatment settings is time efficient and may increase the detection of previously unrecognized PTSD. D 2006 Elsevier Ltd. All rights reserved. Keywords: PTSD; Screening; Detection; Diagnosis; Substance use disorders 0306-4603/$ - see front matter D 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.addbeh.2006.02.008 * Corresponding author. Tel.: +1 650 493 5000x23218; fax: +1 650 617 2701. E-mail addresses: Rachel.Kimerling@med.va.gov (R. Kimerling)8 Jodie.Trafton@va.gov (J.A. Trafton)8 brian308@stanford.edu (B. Nguyen). Addictive Behaviors 31 (2006) 2074 – 2079