Posttraumatic stress and autobiographical memory in chronic pain patients.

Background and aims Posttraumatic stress disorder (PTSD) is related to more severe pain among chronic pain patients. PTSD is also related to dysfunctions or biases in several cognitive processes, including autobiographical memory. The autobiographical memories are our memories of specific personal events taking place over a limited amount of time on a specific occasion. We investigated how two biases in autobiographical memory, overgeneral memory style and negative emotional bias were related to pain, PTSD and trauma exposure in chronic pain patients. Methods Forty-three patients with diverse chronic pain conditions were recruited from a specialist pain clinic. The patients were evaluated for psychiatric diagnosis, with a diagnostic interview Mini-International Neuropsychiatric Interview (M.I.N.I) and for exposure to the most common types of traumatic events with the Life Event Checklist (LEC). The patients were tested with the 15-cue-words version of the Autobiographical Memory Test (AMT). In this test the participants are presented verbally to five positive, five neutral and five negative cue words and asked to respond with a personal, episodic memory associated with the cue word. The participant's responses were coded according to level of specificity and emotional valence. Pain intensity was assessed on a Visual Analogy Scale (VAS) and extent of pain by marking affected body parts on a pre-drawn body figure. Comparisons on autobiographical memory were made between PTSD and non-PTSD groups, and correlations were computed between pain intensity and extent of pain, trauma exposure and autobiographical memory. Results PTSD and extent of pain were significantly related to more negatively emotionally valenced memory responses to positive and negative cue words. There were no significant difference in response to neutral cue words. PTSD status and pain intensity were unrelated to overgeneral autobiographical memory style. Conclusions A memory bias towards negatively emotionally valenced memories is associated with PTSD and extent of pain. This bias may sustain negative mood and thereby intensify pain perception, or pain may also cause this memory bias. Contrary to our expectations, pain, trauma exposure and PTSD were not significantly related to an overgeneral memory style. Implications Cognitive therapies that have an ingredient focusing on amending memory biases in persons with comorbid pain and PTSD might be helpful for this patient population. Further investigations of negative personal memories and techniques to improve the control over these memories could potentially be useful for chronic pain treatment.