Behavioural and Cognitive Psychotherapy, 2014, 42, 211–223 First published online 15 February 2013 doi:10.1017/S1352465812001129 The Relationship between Perfectionism and Rumination in Post Traumatic Stress Disorder Sarah J. Egan, Mary Hattaway and Robert T. Kane Curtin University, Perth, Australia Background: To date no research has investigated the link between Post Traumatic Stress Disorder (PTSD) and perfectionism in a clinical sample. Aims: The aim of the current study was to examine whether there is a relationship between PTSD and perfectionism. This is important to address as many studies have demonstrated a link between other anxiety disorders, eating disorders, depression and perfectionism. The research also aimed to examine whether rumination was a mediator of the relationship between PTSD and perfectionism. Method: The sample consisted of 30 participants who were currently in treatment for PTSD. Results: The results suggest that perfectionism and PTSD symptoms were significantly correlated. In addition, rumination was a significant mediator of the relationship between Concern over Mistakes and PTSD. Conclusions: These findings help increase understanding about the relationships of perfectionism and rumination in PTSD and have implications for the treatment of PTSD. Keywords: Post traumatic stress disorder, perfectionism, rumination, transdiagnostic. Introduction Population estimates report as many as 65% of individuals have experienced a traumatic event, with 5% estimated to have experienced Post Traumatic Stress Disorder (PTSD) in their lives (Australian Centre for Posttraumatic Mental Health, 2007). Recognizing that most people recover in the first 3 months following trauma poses the question as to why only some people develop PTSD? Furthermore, which factors aid and which impede recovery (Cahill and Foa, 2007)? A potentially useful line of inquiry may be to examine cognitive factors that are known to be risk and maintaining mechanisms in order to determine the influence of these on PTSD as they may be particularly salient processes that have been overlooked in understanding PTSD. Rumination and perfectionism This study examines whether cognitive processes that have been found to be elevated across numerous disorders, namely perfectionism and rumination, are associated with PTSD symptoms. Perfectionism is elevated in eating disorders, depression, and the anxiety disorders of Obsessive-Compulsive Disorder, Panic Disorder, and Social Phobia (Egan, Wade and Reprint requests to Sarah Egan, School of Psychology and Speech Pathology, Curtin University, GPO Box U1987, Perth, WA 6845, Australia. E-mail: s.egan@curtin.edu.au © British Association for Behavioural and Cognitive Psychotherapies 2013