Objective: Several studies have provided prevalence estimates of posttraumatic stress disorder (PTSD) related to the September 11, 2001 (9/11) attacks in broadly affected populations, although without sufficiently addressing qualifying exposures required for assessing PTSD and estimating its prevalence. A premise that people throughout the New York City area were exposed to the attacks on the World Trade Center (WTC) towers and are thus at risk for developing PTSD has important implications for both prevalence estimates and service provision. This premise has not, however, been tested with respect to DSM-IV-TR criteria for PTSD. This study examined associations between geographic distance from the 9/11 attacks on the WTC and reported 9/11 trauma exposures, and the role of specific trauma exposures in the development of PTSD.
Methods: Approximately 3 years after the attacks, 379 surviving employees (102 with direct exposures, including 65 in the towers, and 277 with varied exposures) recruited from 8 affected organizations were interviewed using the Diagnostic Interview Schedule/Disaster Supplement and reassessed at 6 years. The estimated closest geographic distance from the WTC towers during the attacks and specific disaster exposures were compared with the development of 9/11–related PTSD as defined by the Diagnostic and Statistical Manual, Fourth Edition, Text Revision.
Results: The direct exposure zone was largely concentrated within a radius of 0.1 mi and completely contained within 0.75 mi of the towers. PTSD symptom criteria at any time after the disaster were met by 35% of people directly exposed to danger, 20% of those exposed only through witnessed experiences, and 35% of those exposed only through a close associate’s direct exposure. Outside these exposure groups, few possible sources of exposure were evident among the few who were symptomatic, most of whom had preexisting psychiatric illness.
Conclusions: Exposures deserve careful consideration among widely affected populations after large terrorist attacks when conducting clinical assessments, estimating the magnitude of population PTSD burdens, and projecting needs for specific mental health interventions.
(Disaster Med Public Health Preparedness. 2011;5:S205-S213)
(Received May 31 2011)
(Accepted July 08 2011)
c1 Correspondence: Address correspondence and reprint requests to Dr Carol S. North, Department of Psychiatry, University of Texas Southwestern Medical Center, 6363 Forest Park Rd, Suite 651, Mail Code 8828, Dallas, TX 75390-8828 (e-mail: Carol.North@UTSouthwestern.edu).
Author Affiliations: Dr North is with the VA North Texas Health Care System and the Departments of Psychiatry and Surgery/Emergency Medicine, University of Texas Southwestern Medical Center; Dr Pollio is with the University of Alabama, School of Social Work; Dr Smith is with the Mount Sinai School of Medicine, Department of Psychiatry; Dr King is with the Departments of Health Care Sciences and Surgery/Emergency Medicine, University of Texas Southwestern Medical Center; Dr Pandya is with the Cedars-Sinai Medical Center Department of Psychiatry, Disaster Psychiatry Outreach, and the UCLA School of Medicine, Department of Psychiatry, Los Angeles; Dr Surís is with the VA North Texas Health Care System and the Department of Psychiatry, University of Texas Southwestern Medical Center; Dr Hong is with the Department of Psychiatry, Washington University School of Medicine; Dr Dean is with the Geography and Geospatial Information Sciences Program, University of Texas at Dallas; Ms Wallace is an international mental health consultant and adjunct faculty, New York University Silver School of Social Work; Dr Herman is with the New York State Psychiatric Institute and Department of Psychiatry, College of Physicians & Surgeons, Columbia University; Ms Conover is with the Department of Psychiatry, Columbia University; Dr Susser is with the Departments of Epidemiology and Psychiatry, Mailman School of Public Health, Columbia University and New York State Psychiatric Institute; and Dr Pfefferbaum is with the Department of Psychiatry and Behavioral Sciences, College of Medicine, University of Oklahoma Health Sciences Center.