Sufficient conditions for effective psychological treatment of chronic pain: a qualitative comparative analysis

Chronic pain (CP) is the leading cause of years lived with disability globally. Treatment within Western medicine is often multicomponent; the psychological element of treatment varies, yet the optimal conditions for effective reduction of pain-related outcomes remain unclear. This study used qualitative comparative analysis, a relatively new form of evidence synthesis in the field based on set theory to ascertain configurations of intervention components and processes of psychological treatment of chronic pain in adults that lead to more effective interventions. Data were extracted from 38 studies identified in a concurrent Cochrane review and were then subjected to qualitative comparative analysis. Two analyses were conducted: one to examine what is most effective for reducing disability and one to examine what is most effective for reducing distress. Analysis and comparison of the 10 treatments with best outcomes with the 10 treatments with poorest outcomes showed that interventions using graded exposure, graded exercise or behavioural rehearsal (exposure/activity), and interventions aiming to modify reinforcement contingencies (social/operant) reduced disability levels when either approach was applied but not both. Exposure/activity can improve distress levels when combined with cognitive restructuring, as long as social/operant methods are not included in treatment. Clinical implications of this study suggest that treatment components should not be assumed to be synergistic and provided in a single package.