Latent typologies of posttraumatic stress disorder in World Trade Center 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)
References (75)
- et al.
Exploring negative emotion in women experiencing intimate partner violence: shame, guilt and PTSD
Behav. Ther.
(2011) - et al.
The interactive effects of emotional clarity and cognitive reappraisal in posttraumatic stress disorder
J. Anxiety Disord.
(2012) - et al.
Emotion regulation difficulties in trauma survivors: the role of trauma type and PTSD symptom severity
Behav. Ther.
(2010) - et al.
Coping and PTSD symptoms in Pakistani earthquake survivors: purpose in life, religious coping and social support
J. Affect. Disord.
(2013) - et al.
The neural bases of emotion regulation: reappraisal and suppression of negative emotion
Biol. Psychiatry
(2008) - et al.
Latent classes of PTSD symptoms in Iraq and Afghanistan female veterans
J. Affect. Disord.
(2014) - et al.
Anhedonia and emotional numbing in combat veterans with PTSD
Behav. Res. Ther.
(2006) - et al.
Typologies of posttraumatic stress disorder in the US adult population
J. Affect. Disord.
(2014) - et al.
The burden of full and subsyndromal posttraumatic stress disorder among police involved in the World Trade Center rescue and recovery effort
J. Psychiatr. Res.
(2012) - et al.
Support for a novel five-factor model of posttraumatic stress symptoms in three independent samples of Iraq/Afghanistan veterans: a confirmatory factor analytic study
J. Psychiatr. Res.
(2012)
Trajectories of posttraumatic stress symptomatology in older persons affected by a large-magnitude disaster
J. Psychiatr. Res.
Jr. Slow and rapid onset of manic episodes: implications for underlying biology
Psychiatr. Res.
Persistence of multiple illnesses in World Trade Center rescue and recovery workers: a cohort study
Lancet
World Trade Center disaster and sensitization to subsequent life stress: a longitudinal study of disaster responders
Prev. Med.
Post-disaster stressful life events and WTC-related posttraumatic stress, depressive symptoms, and overall functioning among responders to the World Trade Center disaster
J. Psychiatr. Res.
When more is not better: the role of cumulative risk in child behavior outcomes
J. Child Psychol. Psychiatry
SSRIs versus non-SSRIs in post-traumatic stress disorder
Drugs
Typologies of posttraumatic stress disorder in treatment-seeking older adults
Int. Psychogeriatr.
Psychometric properties of the PTSD checklist for diagnostic and statistical manual of mental disorders- fifth edition (PCL-5) in veterans
Psychol. Assess.
Gender differences in probable posttraumatic stress disorder among police responders to the 2001 World Trade Center terrorist attack
Am. J. Ind. Med.
Longitudinal mental health impact among police responders to the 9/11 terrorist attack
Am. J. Ind. Med.
The structure of posttraumatic stress disorder: latent class analysis in 2 community samples
Arch. General Psychiatry
Meta-analysis of risk factors for posttraumatic stress disorder in trauma-exposed adults
J. Consult. Clin. Psychol.
DSM-IV post-traumatic stress disorder among World Trade Center responders 11–13 years after the disaster of 11 September 2001 (9/11)
Psychol. Med.
Chronic probable PTSD in police responders in the World Trade Center Health Registry ten to eleven years after 9/11
Am. J. Ind. Med.
Social bonds and posttraumatic stress disorder
Annu. Rev. Psychol.
Prevalence and predictors of posttraumatic stress symptoms in utility workers deployed to the World Trade Center following the attacks of September 11, 2001
Depress. Anxiety
The use of latent trajectory models in psychopathology research
J. Abnorm. Psychol.
Cohort profile: World trade Center health program general responder cohort
Int. J. Epidemiol.
Prolonged Exposure Therapy for PTSD: Emotional Processing of Traumatic Experiences Therapist Guide
Education, vulnerability, and resilience after a natural disaster
Ecol. Soc. A J. Integr. Sci. Resil. Sustain.
Psychological sequelae of the September 11 terrorist attacks in New York City
N. Engl. J. Med.
Risk factors for PTSD and other diagnoses in a general sample of Vietnam veterans
Am. J. Psychiatry
Behavioral activation and therapeutic exposure: an investigation of relative symptom changes in PTSD and depression during the course of integrated behavioral activation, situational exposure, and imaginal exposure techniques
Behav. Modif.
Post-traumatic stress disorder: a review of psychobiology and pharmacotherapy
Acta Psychiatr. Scand.
Combat guilt and its relationship to PTSD symptoms
J. Clin. Psychol.
The World Trade Center disaster and the health of workers: five-year assessment of a unique medical screening program
Environ. Health Perspect.
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2020, Journal of Psychiatric ResearchCitation Excerpt :These comparisons confirm that rescue workers are a group at high risk of developing PTSD, although some other studies have found apparently contradictory results. Studies on the personnel involved in the World Trade Centre (WTC) rescue and recovery effort, in fact, showed relevant PTSD rates in police workers, despite lower than in other professional categories not directly implicated in the catastrophe (Pietrzak et al., 2014; Horn et al., 2016; Diab et al., 2017). Similarly, in other samples of subjects specialized in the recovery of victims of natural disasters, no significant changes were found in the psychopathological evaluations before and after the disaster (Van der Velden et al., 2012), suggesting the important role of resilience factors, in particular professional preparation.