A Rational Emotive Behaviour Therapy Perspective on the Nature and Structure of Posttraumatic Stress Responses: The Mediating and Moderating Effects of Rational and Irrational Beliefs.

Rational Emotive Behaviour Therapy (REBT: Ellis, 2001) represents the original cognitive-behavioural therapy (CBT) model of psychopathology. Although there is much empirical support for the basic theory of REBT (see David, Lynn, & Ellis, 2010), the model has never been tested in the context of posttraumatic stress responses to adverse life events. The first empirical chapter of the thesis investigated the construct validity of the Attitudes and Belief Scale 2 (ABS-2: DiGiuseppe, Leaf, Exner, & Robin, 1988). This chapter employed traditional confirmatory factor analysis and confirmatory bifactor modelling to investigate the psychometric properties of the ABS-2. Results indicated that a bifactoral model conceptualisation was found to offer an adequate representation of the underlying factor structure of the scale. Based on these results, an abbreviated version of the ABS-2 with superior psychometric properties was thus constructed. In the second empirical chapter confirmatory bifactor modelling and composite reliability analysis were employed to investigate the psychometric properties of the Profile of Emotional Distress (PED: Opris & Macavei, 2007). The PED was designed to capture the qualitative distinction between dysfunctional emotions, as predicted by REBT theory. Results indicated that the PED does not capture the distinction between functional and dysfunctional negative emotions, however a bifactor model inclusive of a single general distress factor, and four method factors was found to be an acceptable fit of the data. The third empirical chapter utilised structural equation modelling to test the organisation of the irrational beliefs in the prediction of posttraumatic stress responses. A model consistent with the predictions of REBT theory was found to be a good fit of the data and explained a large percentage of variance in each symptom class of posttraumatic stress. The fourth empirical chapter provided the first piece of empirical evidence that generalised irrational beliefs impact upon posttraumatic stress symptoms via traumaspecific irrational beliefs; a frequently hypothesised relationship which had hitherto remained untested. Results of structural equation modelling offered support for this core hypothesis. Subsequently, the fifth empirical chapter investigated the impact of traumaspecific irrational beliefs in the prediction of reporting posttraumatic stress symptoms while controlling for a number of important sociodemographic factors. Binary logistic regression analysis was employed and found that three irrational belief process positively predicted belong to the strongly symptomatic group. Finally, the sixth empirical chapter employed sequential moderated multiple regression analysis to determine if rational beliefs could positively moderate the impact of irrational beliefs of posttraumatic stress symptoms. Rational beliefs were found to exert a negative, direct effect on posttraumatic stress symptoms, and to lessen the impact of irrational beliefs on posttraumatic stress responses