Posttraumatic stress disorder and psychophysiological reactivity in female assault survivors: testing the moderating effects of internalizing and externalizing latent dimensions of psychopathology
Orazem, Robert J.
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This study examined individual variability in the strength of association between psychophysiological reactivity to trauma cues and clinician-rated PTSD symptoms in a sample of female survivors of sexual and non-sexual assault. PTSD is a heterogeneous disorder, and individual differences in symptom presentation and accompanying comorbidities may be accounted for by internalizing and externalizing latent temperament-based dimensions of psychopathology. The present study proposed that these dimensions may also account for heterogeneity in the association between psychophysiological reactivity and PTSD. Prior research has demonstrated that most individuals with PTSD display elevated psychophysiological reactivity when exposed to trauma reminders, although some do not. As well, research has shown that externalizing pathologies are typically associated with diminished psychophysiological reactivity to aversive cues whereas internalizing pathologies are associated with elevated psychophysiological reactivity. This study therefore employed structural equation modeling to test hypotheses that externalizing and internalizing pathologies would display mitigating and enhancing moderator effects, respectively, on the prediction of PTSD by psychophysiological reactivity. To that end, confirmatory factor analysis first established a viable internalizing and externalizing model based on an array of clinical measures in one participant subgroup (n = 329) and then affirmed the reliability of the model in a second subgroup (n = 245). Structural equation modeling in the latter subgroup, in which PTSD was regressed on Internalizing, Externalizing, and Psychophysiological Reactivity factors as well as Internalizing by Psychophysiological Reactivity and Externalizing by Psychophysiological Reactivity moderator terms, revealed a significant moderator effect for externalizing but not internalizing pathology. However, the nature of the externalizing moderator effect differed from the hypothesized direction, with higher levels of externalizing pathology strengthening the association between PTSD and psychophysiological reactivity rather than weakening it. It therefore appears that variability in the association between PTSD and psychophysiological reactivity may be partially accounted for by individual differences in the externalizing dimension of psychopathology. As well, the psychophysiology of the externalizing dimension may also be marked by heterogeneity, with externalizing pathology being linked with increased rather than decreased psychophysiological reactivity among women who have experienced sexual or non-sexual assault.