Trauma Centrality and PTSD Symptom Severity in Adult Survivors of Childhood Sexual Abuse

Theorists have posited that regarding a trauma as central to one's identity leads to greater posttraumatic stress disorder (PTSD) symptom severity. To test this hypothesis, we administered the Centrality of Events Scale (CES) to women reporting a history of childhood sexual abuse (N = 102). The CES scores were correlated with PTSD symptom severity, depression severity, and self-esteem. In addition, we conducted a principal component analysis (PCA) to evaluate factors underlying the CES. The PCA yielded 3 factors reflecting (a) the centrality and integration of the trauma, (b) whether the event is regarded as a turning point in one's life story, and (c) whether the event is a reference point for expectations about the future. Each factor was associated with PTSD symptom severity.

Trauma Centrality and PTSD Symptom Severity in Adult Survivors of Childhood Sexual Abuse Accessible, vivid, and affectively intense memories structure our autobiographical narratives, inform our sense of self, and act as reference points for our expectations and attributions in everyday life (Berntsen & Rubin, 2007).Increasingly, researchers are using Berntsen and Rubin's (2006) Centrality of Events Scale (CES) to examine the impact of regarding a trauma as a central aspect of one's identity.CES scores for traumatic or highly aversive events are positively associated with PTSD symptom severity among undergraduates (e.g., Berntsen & Rubin, 2006, 2007;Robinaugh & McNally, 2010).and among combat veterans (Brown, Antonius, Kramer, Root, & Hirst, 2010).
Although CES items load onto a single centrality-of-event factor (Berntsen & Rubin, 2006), Berntsen and Rubin developed the scale to assess three presumably distinct constructs.
The first denotes the extent to which one regards an event as a turning point in one's life story.
The second denotes the extent to which the event is central to one's identity.Although these constructs have their theoretical roots in the autobiographical memory literature (e.g., Pillemer, 1998), they are also relevant to several theories of PTSD.In particular, cognitive theorists have highlighted the etiological importance of negative trauma-related self-appraisals (Brewin & Holmes, 2003).These self-appraisals (e.g., "I have permanently changed for the worse " Foa, Ehlers, Clark, Tolin, & Orsillo, 1999) resemble items on the CES (e.g., "This event permanently changed my life.").Accordingly, a positive association between these constructs and PTSD severity is consistent with both cognitive (e.g., Ehlers & Clark, 2000) and mnemonic (Rubin, Berntsen, & Bohni, 2008) models of PTSD.The third construct concerns the extent to which the event acts as a reference point structuring the organization of autobiographical memory and informing attributions and expectations.Several PTSD models (e.g., Ehlers & Clark, 2000;Herman, 1992) hold that a failure to integrate a traumatic event with other autobiographical memories contributes to the development of PTSD.In contrast, others have argued that greater integration of the trauma heightens its accessibility, promotes voluntary and involuntary retrieval, and worsens PTSD (Berntsen & Rubin, 2007).These researchers cite the positive association between CES scores and PTSD as evidence that greater integration leads to greater PTSD (Berntsen & Rubin, 2007).However, items addressing the "identity" and "turning point" constructs may drive this positive association rather than those addressing the integration of the trauma with other autobiographical memories.Accordingly, there is a need to examine the association between each CES construct and posttraumatic distress.
In this study, we tested whether greater CES scores would be associated with greater psychological distress and poorer self-esteem in women reporting a history of childhood sexual abuse (CSA).Furthermore, we hypothesized that CES scores would remain associated with PTSD symptom severity after we controlled for depression severity, self-esteem, and two risk factors for PTSD: intelligence (McNally & Shin, 1995) and dissociation (Ozer, Best, Lipsey, & Weiss, 2003).Finally, we conducted a principal component analysis (PCA) to uncover the three CES constructs, and to test whether there is a positive association between each of them and psychological distress.

Method Participants
The subjects were women who reported a history of CSA (n = 102) who responded to our advertisement for a study on risk and resilience.Fifty-two percent were Caucasian, and their mean age was 42.5 years (SD = 12.1).A phone screen confirmed that each woman had experienced at least one episode of sexual abuse prior to the age of 17 involving physical contact with (e.g., fondling, oral-genital contact,) a perpetrator who was at least five years older than the victim was.The Institutional Review Board of Harvard University approved the protocol and consent form.Participants provided written informed consent.

Measures
Centrality of Events Scale.The CES (Berntsen & Rubin, 2006) is a 20-item questionnaire with items rated on a scale of 1 (Strongly Disagree) to 5 (Strongly Agree).We asked participants to rate items in reference to the CSA.Following Berntsen and Rubin, we calculated the CES score as the mean of all items.
For the PCL, participants rated each item in reference to the CSA.In addition, we administered the Rosenberg Self-Esteem Scale (RSS; Rosenberg, 1965, pp. 305-307) to assess self-esteem.
Risk factors for PTSD.To assess intelligence, we administered Shipley Institute for Living Scale (Zachary, 1991) and converted each subject's score into its estimated WAIS-R equivalent.We administered the Dissociative Experiences Scale (DES; Bernstein & Putnam, 1986) to assess dissociation.

Results
We calculated product-moment correlations among the CES, PCL, BDI, RSS, and DES scores (Table 1).CES scores were positively associated with each variable.We next conducted a single-step multiple linear regression analysis to determine if CES scores were associated with PTSD symptom severity after we controlled statistically for age, intelligence, and BDI, RSS, and DES scores (see Table 2).CES continued to predict PTSD symptom severity (β = .43,p < .001).

TRAUMA CENTRALITY IN CSA 6
To examine the factors underlying the CES, we performed an iterated principal component analysis (PCA) with varimax rotation 1 .The PCA produced 4 factors with eigenvalues exceeding the Kaiser criterion (9.88, 1.54, 1.16, and 1.04;Kaiser, 1960).The inflexion point of the Scree plot (Cattell, 1966) occurred at the 3 rd eigenvalue.Accordingly, we evaluated both a three-factor and four-factor solution.Relative to the four-factor solution, the three-factor solution produced a more clearly interpretable pattern of findings.In the three-factor rotated solution (see Table 3), Factors 1, 2, and 3 accounted for 23.49%, 19.96%, and 19.42% of the variance in CES items, respectively.Finally, we calculated the product-moment correlations between the three factor scores and RSS, PCL, and BDI scores (Table 1).Each factor was associated with PCL scores.

Discussion
Researchers have reported a positive association between CES scores and PTSD symptom severity in undergraduate students and combat veterans (Berntsen & Rubin, 2006;Brown et al., 2010).In this study, we extended these findings to women reporting a history of childhood sexual abuse.CES scores were positively associated with PTSD and depression symptom severity and negatively associated with self-esteem.The association between CES scores and PTSD remained significant after we controlled statistically for depression severity, self-esteem, age, intelligence, and dissociation.
PCA revealed that the CES contains three factors that closely, though not precisely, reflect the constructs that Berntsen and Rubin (2006) designed it to address.Factor 1 contained items tapping both centrality to identity and the integration with other memories.This factor was positively associated with PTSD symptom severity, implying that greater integration contributes to greater severity of PTSD.Factor 2 contained items addressing whether one considers the TRAUMA CENTRALITY IN CSA 7 event as a turning point in one's life (i.e., having been changed by the event); it, too, was positively associated with PTSD severity.Factor 3 predominately contained items addressing the extent to which victims view the future through the lens of CSA.Interestingly, this factor exhibited a notably greater association with PTSD symptom severity than did the "Centrality" and "Turning Point" factors, suggesting that holding a traumatic event as central to one's future may be more psychologically toxic than appraising the event as a key to one's current identity.
Our study has limitations.The data are cross-sectional, precluding determination of causality.In addition, although our sample size exceeded the minimum recommended subject-toitem ratio (Gorusch, 1983, p. 32), it was modest for exploratory factor analysis (Comfrey & Lee, 1992).Furthermore, several items loaded highly on multiple factors.Given previous findings that CES items load onto a single factor (Berntsen & Rubin, 2006), these limitations suggest some caution may be warranted in interpreting our PCA results .
The PTSD field lacks a consensus definition of what it means to "integrate" a trauma into one's life story.We interpreted integration as the extent to which victims perceive connections between the trauma and other autobiographical memories.By this definition, greater integration was associated with greater PTSD symptom severity.The implications of our results for alternative conceptualizations of integration are unclear.
Individuals who appraise a traumatic event as a turning point in their life story, a central part of their identity, and a reference point for generating expectations about the future exhibit greater distress.Our results suggest that individuals who appraise a traumatic event as a reference point for their future may be especially at risk for PTSD..57.30.59 1.This event has become a reference point for the way I understand new experiences.
.18 .15.58 13.This event has become a reference point for the way I look upon my future.

Table 1
Pearson product-moment correlations My life story can be divided into two main chapters: one is before and one is after this event happened.