PTSD and Comorbid Depression: Social Support and Self-Efficacy in World Trade Center Tower Survivors 14-15 Years After 9/11

Objective: Following the World Trade Center (WTC) terrorist attack in New York City, prevalence rates of posttraumatic stress disorder (PTSD) and depression remain elevated. Although social support and self-efficacy have been associated with PTSD, little is known about their differential effect on PTSD and depressive comorbidity. Method: WTC tower survivors (n = 1,304) were assessed at Wave 1 (2003-2004), Wave 2 (2006-2007), Wave 3 (2011-2012), and Wave 4 (2015-2016). Results: At Wave 4, 13.0% of participants had probable PTSD, a decrease from 16.5% at Wave 1. In addition, 4.1% (54) were identified as having PTSD alone, 6.8% (89) had depression alone, and 8.9% (116) had comorbid PTSD and depression. Of those with PTSD, 68.2% also had comorbid depression. WTC tower survivors with PTSD and comorbid depression reported greater PTSD symptom severity and were more likely to have had greater exposure to the events of 9/11 (adjusted odds ratio [aOR] = 1.14) and lower self-efficacy (aOR = 0.85) than those with depression alone. Less perceived social support predicted only depression and not PTSD, whereas less perceived self-efficacy equally predicted having PTSD or depression (aOR = 0.76). Conclusions: Findings indicate that self-efficacy may be more important to the severity and chronicity of PTSD symptoms than social support. Multivariate comparisons suggest that PTSD with comorbid depression is a presentation of trauma-dependent psychopathologies, as opposed to depression alone following trauma, which was independent of trauma exposure and may be secondary to the traumatic event and posttraumatic response. Implications for assessment and treatment are discussed. Clinical Impact Statement PTSD with comorbid depression shared a trauma-related etiology with increased symptom severity and unique risk factors that was largely dependent on self-efficacy rather than social support. Depression alone following trauma was not directly related to trauma exposure and likely secondary to the posttraumatic response and subsequent stressors. PTSD and depressive comorbidity is likely a trauma or stressor-related presentation and sub-type of PTSD that is distinct from depression alone following trauma. Interventions that target the processing of traumatic experiences and enhancement of self-efficacy and agency may be more effective in treating PTSD with comorbid depression than interventions that target interpersonal relationships.