Elsevier

Journal of Psychiatric Research

Volume 83, December 2016, Pages 151-159
Journal of Psychiatric Research

Latent typologies of posttraumatic stress disorder in World Trade Center responders

https://doi.org/10.1016/j.jpsychires.2016.08.018Get rights and content

Abstract

Posttraumatic stress disorder (PTSD) is a debilitating and often chronic psychiatric disorder. Following the 9/11/2001 World Trade Center (WTC) attacks, thousands of individuals were involved in rescue, recovery and clean-up efforts. While a growing body of literature has documented the prevalence and correlates of PTSD in WTC responders, no study has evaluated predominant typologies of PTSD in this population. Participants were 4352 WTC responders with probable WTC-related DSM-IV PTSD. Latent class analyses were conducted to identify predominant typologies of PTSD symptoms and associated correlates. A 3-class solution provided the optimal representation of latent PTSD symptom typologies. The first class, labeled “High-Symptom (n = 1,973, 45.3%),” was characterized by high probabilities of all PTSD symptoms. The second class, “Dysphoric (n = 1,371, 31.5%),” exhibited relatively high probabilities of emotional numbing and dysphoric arousal (e.g., sleep disturbance). The third class, “Threat (n = 1,008, 23.2%),” was characterized by high probabilities of re-experiencing, avoidance and anxious arousal (e.g., hypervigilance). Compared to the Threat class, the Dysphoric class reported a greater number of life stressors after 9/11/2001 (OR = 1.06). The High-Symptom class was more likely than the Threat class to have a positive psychiatric history before 9/11/2001 (OR = 1.7) and reported a greater number of life stressors after 9/11/2001 (OR = 1.1). The High-Symptom class was more likely than the Dysphoric class, which was more likely than the Threat class, to screen positive for depression (83% > 74% > 53%, respectively), and to report greater functional impairment (High-Symptom > Dysphoric [Cohen d = 0.19], Dysphoric > Threat [Cohen d = 0.24]). These results may help inform assessment, risk stratification, and treatment approaches for PTSD in WTC and disaster responders.

Introduction

Posttraumatic stress disorder (PTSD) is a prevalent, often chronic, and debilitating psychiatric disorders worldwide (Karam et al., 2014). Following the September 11, 2001 terrorist attacks on the World Trade Center (WTC), tens of thousands of individuals were involved in rescue, recovery and clean-up efforts. This diverse group of responders included traditional first responders (police officers) as well as non-traditional responders without prior disaster training (e.g., construction workers and volunteers) (Herbert et al., 2006, Pietrzak et al., 2014a). While the prevalence, correlates and longitudinal course of PTSD symptomatology have been well-documented in WTC responders (Bowler et al., 2012, Bromet et al., 2015, Cone et al., 2015, Luft et al., 2012, Perrin et al., 2007, Pietrzak et al., 2012a, Pietrzak et al., 2014a, Stellman et al., 2008, Wisnivesky et al., 2011, Zvolensky et al., 2015b), no study of which we are aware has evaluated predominant typologies of PTSD symptomatology in this population. Such information is important, as it can inform assessment, risk stratification, and treatment approaches for symptomatic WTC and other disaster responders.

Latent class analysis (LCA) is a data analytic approach often used to identify subgroups of individuals within a larger sample that cluster together based on predominant symptom typologies (Curran and Hussong, 2003, Muthén and Muthén, 2012, Nagin and Tremblay, 2001). A growing body of studies has utilized latent class/profile analyses to identify predominant PTSD symptom typologies in a broad range of traumatized populations, including civilian trauma survivors, combat veterans, and sexual assault survivors (Böttche et al., 2015, Breslau et al., 2005, Hebenstreit et al., 2014, Pietrzak et al., 2014b). Several of the preceding studies applied LCA in trauma-exposed populations with the full spectrum of PTSD symptom severity, including very low or no symptoms, resulting in class solutions focused primarily on levels of “disturbance” or symptom severity (Breslau et al., 2005). For example, an LCA in two large community samples of trauma-exposed respondents yielded 3 classes: no disturbance, intermediate disturbance and pervasive disturbance (Breslau et al., 2005).

More recent studies have aimed to identify latent symptom typologies in samples of individuals meeting criteria for PTSD or probable PTSD (Böttche et al., 2015, Hebenstreit et al., 2014, Pietrzak et al., 2014b). One study found a 4-class LCA solution in a sample of 2425 female veterans with a PTSD diagnosis: High Symptom, Intermediate Symptom, Intermediate Symptom with High Emotional Numbing and Low Symptom (Hebenstreit et al., 2014). Another study employing LCA in a sample of 164 treatment-seeking older adults found that a 3-class solution best fit the data (Intermediate Disturbance, Pervasive Disturbance-Low Avoidance and Pervasive Disturbance-High Avoidance) (Böttche et al., 2015). Overall, the aforementioned LCA studies in PTSD resulted in differentiation of classes by severity, and initial differentiation by symptom clusters.

The current study employs LCA to characterize predominant typologies of PTSD symptoms in WTC responders and diverges from previous LCA studies in its approach aimed at characterizing symptom cluster-based typologies. To our knowledge, this is the largest study of its kind to date. A recent study of a nationally representative sample of 2463 U.S. adults with PTSD identified three predominant typologies of PTSD—Anxious Re-experiencing, Dysphoric and High-Symptom typologies—which were differentially associated with trauma characteristics, psychiatric comorbidities, and health-related quality of life (Pietrzak et al., 2014b). Altogether, these studies suggest that PTSD is a heterogeneous disorder characterized by unique symptom profiles that may be differentially linked to trauma and clinical characteristics.

In the current study, we employed LCA in a sample of 4352 WTC responders with a probable diagnosis of WTC-related PTSD. We also examined how sociodemographic characteristics, WTC-related trauma exposures, and psychosocial characteristics related to these typologies of PTSD, and additionally how these typologies related to other clinical characteristics, including comorbid depression, alcohol use problems and functional impairment.

Section snippets

Participants

Participants were 4352 WTC responders with probable DSM-IV PTSD assessed with the PTSD Checklist-Specific Version (PCL-S) (Weathers et al., 1993) (see Assessments section for details). These responders were identified from a cohort of over 32,000 WTC responders who presented for an initial monitoring visit (average 4.5 [SD = 2.4, range = 0.8 to 12.8] years after 9/11/01) at the World Trade Center Health Program (WTC-HP), a regional clinical consortium established by the Centers for Disease

Results

Fit statistics for the LCAs are shown in the top panel of Table 1. Based on theory, parsimony, and fit statistics, a 3-class solution was determined to provide the optimal representation of latent classes of PTSD symptoms in WTC responders. Fig. 1 shows plots of symptom endorsement probabilities by latent class. The first class, labeled “Threat” (n = 1,008, 23.2%), was characterized by high probabilities of re-experiencing, avoidance and anxious arousal symptoms, with an average PCL score of

Discussion

In the current study, LCA analyses identified three predominant classes of PTSD in WTC responders —Threat (23.2%), Dysphoric (31.5%) and High Symptom (45.3%). The Threat class exhibited a PTSD symptom profile characterized by high probabilities of trauma-related fear/anxiety symptoms (e.g., re-experiencing, avoidance and anxious arousal symptoms), while the Dysphoric class exhibited a PTSD symptom profile characterized by high probabilities of anhedonic/depressive symptoms (e.g., emotional

Conflict of interest

Dr. Feder (co-inventor) and Mount Sinai have been named on a use patent application of ketamine for the treatment of posttraumatic stress disorder; patent is currently pending. Dr. Schechter has received consulting fees from Accolade, Inc., for analysis of claims data in evaluation of the effectiveness of their services and for technical support provided to in-house statistical staff. Dr. Crane has received funding from the CDC/NIOSH WTC Health Program contract # 200-2011-39356. Dr. Southwick

Contributors

The following authors contributed to study design: A. Feder, C. Schechter, E. Bromet, C. Katz, M. Crane, D.J. Harrison, R. Herbert, B.J. Luft, J. M. Moline, J.M. Stellman, I.G. Udasin, P.J. Landrigan, S.M. Southwick, and R.H. Pietrzak.

The following authors contributed to study conduct: S.R. Horn, A. Feder, S.M. Southwick, R.H. Pietrzak.

The following authors contributed to manuscript preparation and review: S.R. Horn, A. Feder, C Schechter, E.J. Bromet, C.L. Katz, D.B. Reissman, R. Kotov, J.

Funding source

This work was supported by the CDC/National Institute for Occupational Safety and Health (NIOSH) (A.F., R.H.P. and S.M.S., research contract # 200-2011-41919). The CDC/NIOSH did not contribute to study design; data collection, analysis or interpretation; writing of the report; or decision to submit the manuscript for publication.

Acknowledgment

The authors thank Jamie Schaffer, Olivia Diab, Leo Cancelmo, Ryan Salim, Janice Rodriguez, Ritika Singh, Jared Davis, Peter Awad, Shira Spiel, Kimberly Billera, Kathleen Medrano, Graciela Ramirez, Juan Alcaide, Joel Cruz, Angela Vergara, Kristina Chin, Rina Randriamanantena, Larissa Lai, Abrita Chowdury, Yennifer Moreno, Heather Oli, Navodi Nikeshala and Stephanie Mendes Mateus, student interns and research coordinators who helped field the web-based survey to World Trade Center (WTC)

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