Treatment outcomes in group-based cognitive behavioural therapy for chronic pain: An examination of PTSD symptoms

The relevance of post-traumatic stress disorder (PTSD) symptoms to outcomes of cognitive behavioural therapy (CBT) for chronic pain is unclear. This study examines whether (a) traumatic exposure or the severity of PTSD symptoms at pre-treatment predicts the outcomes (pain intensity/interference), (b) participation in this treatment is associated with reduced PTSD symptoms and (c) any observed changes in PTSD symptoms are mediated by changes in psychological mechanisms that have been shown to be of importance to PTSD and chronic pain.

Participants were 159 chronic pain patients who were consecutively admitted for a multidisciplinary, group-based CBT program at the Pain Rehabilitation Unit at Skåne University Hospital. A self-report measure of traumatic exposure and PTSD symptoms was administered before and after treatment, and at a 12-month follow-up, along with measures of depression, anxiety, pain intensity, pain interference, psychological inflexibility, life control and kinesiophobia.

Traumatic exposure and PTSD symptom severity did not predict pain intensity or interference at 12-month follow-up. There were no overall significant changes in PTSD symptom severity at post-treatment or follow-up, but 24.6% of the participants showed potential clinically significant change at follow-up. Psychological inflexibility mediated the changes that occurred in PTSD symptoms during treatment.

Neither traumatic exposure nor baseline symptoms of PTSD predicted the treatment outcomes examined here. Despite improvements in both comorbid depression and anxiety, participation in this pain-focused CBT program was not associated with improvements in comorbid PTSD. To the extent that changes in PTSD symptoms did occur, these were mediated by changes in psychological inflexibility during treatment.

Pain-focused CBT programs yield clinically meaningful improvements in pain and comorbid symptoms of depression and anxiety, but may have little effect on comorbid PTSD. This raises the issue of whether current pain-focused CBT programs can be modified to improve outcomes for comorbid conditions, perhaps by better targeting of psychological flexibility, and/or whether separate treatment of PTSD may be associated with improved pain outcomes.