Comparing Mechanisms of Change in Group-Based Acceptance and Commitment Therapy to Cognitive Behavioural Therapy in Patients with Chronic Pain
Chronic pain , Acceptance and commitment therapy , Cognitive behavioural therapy
Chronic pain is a costly, debilitating, and prevalent condition that requires biopsychosocial informed interventions for best management. This study aimed to compare acceptance and commitment therapy and cognitive behaviour therapy for chronic pain to determine whether they had differential effects on patient outcomes, on treatment process variables, and whether certain baseline ratings were related to outcomes over time. Chronic pain patients (N = 89) at a tertiary pain clinic were randomized to one of two eight-week therapy programs. Patients completed measures at the initial baseline assessment, after each therapy session, at post-treatment, and at a one-month follow-up appointment. Overall, ACT and CBT performed similarly in improving mental quality of life. Additionally, pain catastrophizing, psychological flexibility, and working alliance changed in both ACT and CBT. These findings suggest that ACT and CBT work through similar mechanisms, even if the mechanisms are not directly addressed in treatment. Baseline levels of psychological flexibility was associated with less pain-related disability, anxiety, depression, and improved physical quality of life indicating that patients with greater psychological flexibility as they enter treatment may benefit the most from psychological interventions. Ratings of neuropathic pain mediated the relationship between chronic pain acceptance and physical quality of life, suggesting that post-treatment neuropathic pain ratings explain some of the relationship between baseline chronic pain acceptance and physical quality of life one-month post-treatment. Additionally, higher levels of committed action at baseline were related to lower levels of anxiety at the end of treatment for only patients in the ACT group. Clinical implications and future research opportunities are discussed.