Psychological Medicine

Original Articles

Dimensional structure and course of post-traumatic stress symptomatology in World Trade Center responders

R. H. Pietrzaka1a2 c1, A. Federa3, C. B. Schechtera4, R. Singha3, L. Cancelmoa3, E. J. Brometa5, C. L. Katza3, D. B. Reissmana6, F. Ozbaya3, V. Sharmaa3, M. Cranea7, D. Harrisona8, R. Herberta7, S. M. Levina7, B. J. Lufta9, J. M. Molinea10, J. M. Stellmana11, I. G. Udasina12, R. El-Gabalawya13, P. J. Landrigana7 and S. M. Southwicka1a2

a1 National Center for Posttraumatic Stress Disorder, VA Connecticut Healthcare System, West Haven, CT, USA

a2 Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA

a3 Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA

a4 Department of Family and Social Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY, USA

a5 Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA

a6 Office of the Director, National Institute for Occupational Safety and Health, Washington, DC, USA

a7 Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA

a8 Department of Environmental Medicine, Bellevue Hospital Center/New York University School of Medicine, New York, NY, USA

a9 Department of Medicine, Division of Infectious Diseases, Stony Brook University, Stony Brook, NY, USA

a10 Department of Population Health, Hofstra North Shore-Long Island Jewish School of Medicine, Great Neck, NY, USA

a11 Department of Health Policy and Management, Mailman School of Public Health, Columbia University, New York, NY, USA

a12 Department of Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ, USA

a13 Departments of Psychology and Psychiatry, University of Manitoba, Winnipeg, Manitoba, Canada


Background Post-traumatic stress disorder (PTSD) in response to the World Trade Center (WTC) disaster of 11 September 2001 (9/11) is one of the most prevalent and persistent health conditions among both professional (e.g. police) and non-traditional (e.g. construction worker) WTC responders, even several years after 9/11. However, little is known about the dimensionality and natural course of WTC-related PTSD symptomatology in these populations.

Method Data were analysed from 10 835 WTC responders, including 4035 police and 6800 non-traditional responders who were evaluated as part of the WTC Health Program, a clinic network in the New York area established by the National Institute for Occupational Safety and Health. Confirmatory factor analyses (CFAs) were used to evaluate structural models of PTSD symptom dimensionality; and autoregressive cross-lagged (ARCL) panel regressions were used to examine the prospective interrelationships among PTSD symptom clusters at 3, 6 and 8 years after 9/11.

Results CFAs suggested that five stable symptom clusters best represent PTSD symptom dimensionality in both police and non-traditional WTC responders. This five-factor model was also invariant over time with respect to factor loadings and structural parameters, thereby demonstrating its longitudinal stability. ARCL panel regression analyses revealed that hyperarousal symptoms had a prominent role in predicting other symptom clusters of PTSD, with anxious arousal symptoms primarily driving re-experiencing symptoms, and dysphoric arousal symptoms primarily driving emotional numbing symptoms over time.

Conclusions Results of this study suggest that disaster-related PTSD symptomatology in WTC responders is best represented by five symptom dimensions. Anxious arousal symptoms, which are characterized by hypervigilance and exaggerated startle, may primarily drive re-experiencing symptoms, while dysphoric arousal symptoms, which are characterized by sleep disturbance, irritability/anger and concentration difficulties, may primarily drive emotional numbing symptoms over time. These results underscore the importance of assessment, monitoring and early intervention of hyperarousal symptoms in WTC and other disaster responders.

(Received August 24 2013)

(Revised October 29 2013)

(Accepted November 02 2013)

(Online publication December 02 2013)

Key words

  • Confirmatory factor analysis;
  • disaster;
  • post-traumatic stress disorder