The effects of distal traumas on posttraumatic stress disorder (PTSD) and co-morbid psychopathology: An integrative memory processing model

Exposure to a traumatic event is a necessary condition in the development of posttraumatic stress disorder (PTSD). Studies have also suggested the presence of intervening variables in its development. However, little research has been reported on the relationships among these intervening factors. This study sought to address this by proposing a mediational model on PTSD and validating it empirically. The proposed Integrative Memory Processing Model specified the effect paths among traumatic events, memory network, appraisal, coping and social support in predicting PTSD. The Model was tested with a sample of one hundred and eleven (111) Cambodian refugees in Toronto, Canada, who survived the Khmer Rogue holocaust in the 1970's. The results were largely supportive of the Model. Other major research questions that this study sought to explain were about the issues of co-morbidity with PTSD, a common clinical phenomenon with little systematic study. In the present study, the specific symptomatic overlap and etiological sharing propositions were investigated with three co-morbid disorders, i.e. anxiety, depression and somatization. The results were supportive of rejecting the specific symptomatic overlap hypothesis and accepting the generalized psychopathology (P) factor proposition. In regard to etiological sharing, the anxiety was found to be predicted by the distal traumatic events whereas both the depression and somatization were only predicted by the current life stress. Implications of the findings in PTSD theory, research and clinical intervention were discussed.