Poor memory as a predictor of poor treatment response in adults diagnosed with posttraumatic stress disorder

Current research has highlighted impaired learning and memory processes in adults diagnosed with Posttraumatic Stress Disorder (PTSD). Although some clients respond favourably to psychological therapy, outcome studies indicate that treatment rarely leads to a full remission of the disorder. Neuroimaging studies of adults with chronic PTSD have suggested altered brain morphology in regions associated with memory functioning, specifically the hippocampus. It is possible that impaired learning and memory processes adversely affect the capability of clients with PTSD to respond to treatment. This study investigated the memory, attention and learning profiles of 27 adults diagnosed with PTSD who presented at a specialist treatment centre prior to commencing cognitive-behavioural therapy. Measures of PTSD, anxiety, depression, and past and current history of alcohol/substance use were obtained on assessment. A neuropsychological test battery was then administered to assess baseline cognitive functioning, memory, learning, attention, and executive function. Twenty-three adults were followed up at session eight of treatment, and their PTSD diagnosis was re-evaluated. Clients who did not improve with treatment had significantly poorer performance on intake measures of verbal memory. In particular, a measure of encoding meaningful verbal material was found to independently predict outcome. Differences were not accounted for by performance on tasks of attention and executive function. Further, severity of PTSD symptomatology, severity of anxiety and depression, length of time since trauma, and alcohol and substance use were not related to memory functioning. The theoretical, clinical, and research implications of this were discussed.