An Investigation of Depression, Trauma History, and Symptom Severity in Individuals Enrolled in a Treatment Trial for Chronic PTSD

Rates of trauma exposure in the US are estimated at 70% of the general population, with approximately 24% of trauma-exposed individuals developing posttraumatic stress disorder (PTSD; Kessler et al., 1995). As evidenced by these high prevalence rates, trauma exposure and resulting psychopathology is a serious mental health issue. A common criticism of treatment research, in psychotherapy trials in general and PTSD trials specifically, is that randomized controlled trials do not include complex, comorbid patients and thus are not generalizable to broader clinical populations (e.g., Seligman, 1995; Weston, 2006). Indeed, by definition controlled treatment trials select for certain patient and treatment factors in order to investigate and explore specific mechanisms of treatment and recovery (Chambless & Crits-Cristoph, 2006). However, the assumption that individuals that participate in treatment research studies are qualitatively different than other patients may be premature, and clinical trial samples may be more complex than is often assumed (e.g., Stirman & DeRubeis, 2006). However, there remains concern that clinical trial samples do not accurately represent the high complexity that is sometimes seen in individuals with PTSD. For example, trauma type (e.g., interpersonal violence, combat, accidents) is often cited as a factor that may influence symptom presentations. Extensive and early traumatic experiences, particularly interpersonal traumas such as childhood physical or sexual abuse, are often identified as likely precipitants of general impairment deficits (e.g., poor psychosocial functioning, emotion dysregulation deficits) accompanying PTSD (e.g., Goodman, 2012; Lindauer, 2012; Terr, 1991; van der Kolk et al., 2005). Specifically, childhood abuse has been proposed to lead not only to an increased likelihood of PTSD compared to other trauma types (Kessler et al., 1995) but also to increased depression (e.g., Browne & Finkelhor, 1986; Paolucci, 2001; Polusny & Follete, 1995), poor social and interpersonal functioning (Cloitre et al., 2005; Cloitre, Petkova, Wang, & Lu, 2012; Zlotnick et al., 1996), increased dissociation (van der Kolk et al., 2005; Zlotnick et al., 1996), and a worse treatment response (e.g., Ford & Kidd, 1998; McDonagh et al., 2005). Similarly, repeated trauma exposure has been hypothesized to result in more severe outcomes than exposure to single incident traumas (Herman, 1992; Zlotnick et al., 1996). Indeed, presence of a trauma history prior to the index event is a predictor of developing PTSD, albeit a generally small size effect (Brewin, Andrews, & Valentine, 2000; Ozer, Best, Lipsey, & Weiss, 2003). Early, prolonged, or repeated traumatic events are thought to have detrimental effects on developmental processes, such as interfering with acquiring adaptive interpersonal and emotion regulation skills, which results in poor functioning beyond the PTSD diagnosis (e.g., Cloitre et al., 2004; Terr, 1991; van der Kolk et al., 2005). However, exposure to multiple traumatic events is common, and more than half of individuals who report exposure to one traumatic event report exposure to multiple traumatic events (Kessler et al., 1995). Regardless, both childhood abuse and repeated trauma exposure are considered to be associated with poor adjustment and increased severity of functioning (e.g., Goodman, 2012; Lindauer, 2012). The relationship between trauma type and severity may be better explained by associated depression. Depressive symptoms are common following childhood traumatic events (Browne & Finkelhor, 1986; Cloitre, Koenen, Cohen, & Han, 2002; Cloitre et al., 2005; Mullen, Romans-Clarkson, Walton, & Herbison, 1988; Zlotnick et al., 1996), and PTSD commonly co-occurs with major depressive disorder (MDD) in both childhood and adulthood (Kessler et al., 1995). Large-scale studies have reported that as many as 51% to 87% of individuals with PTSD exhibit co-occurring MDD (Hankin, Spiro, Miller, & Kazis, 1999; Rytwinski, Scur, Feeny, & Youngstrom, 2013; Shore, Vollmer, & Tatum, 1989). Moreover, epidemiological studies show significant increases in odds ratios for lifetime MDD in individuals with PTSD (Davidson, Hughes, Blazer, & George, 1991; Helzer, Robins, & McEvoy, 1987; Kessler et al., 1995; Kessler, Chiu, Demler, & Walters, 2005), and the presence of MDD in addition to PTSD predicts greater impairment (Breslau, Davis, Andreski, & Peterson, 1991; Post, Zoellner, Youngstrom, & Feeny, 2011) and possibly worse treatment outcome (e.g., Green, Grace, Lindy, Gleser, & Leonard, 1990). This suggests that co-occurring PTSD and MDD may represent a more severe form of disorder than PTSD alone. In other words, co-occurring MDD may be considered a complicating factor for individuals with PTSD regardless of trauma type. Accordingly, depressive symptoms may better account for greater symptom severity and worse functioning than trauma history, especially given that trauma history is a temporally distal predictor of functioning while depressive symptoms are a more proximal predictor that is occurring concurrent with the individual’s PTSD symptoms. Overall, given the overlap of co-occurring diagnoses such as MDD, multiple traumas, and childhood abuse, it is worthwhile to understand better specifically who is most likely to present with more severe expressions of PTSD. In a sample of patients enrolled in a clinical treatment trial for chronic PTSD, we examined the relationship between childhood abuse index trauma, a history of childhood abuse, high level of exposure to multiple traumatic events, and co-occurring MDD, as well as indices of broader functioning. We hypothesized that these factors would be associated with greater symptom severity, worse functioning, higher dissociation, more extensive treatment history, and greater additional co-occurring diagnoses. In addition to examining the above hypotheses, we also examined the prevalence of pure presentations of PTSD, characterized by single incident trauma exposure and a lack of comorbidity, in order to examine whether this present PTSD clinical trial included a preponderance of “simple” or “pure” PTSD.