Confirming the mechanisms behind cognitive-behavioural therapy effectiveness in chronic pain using structural equation modeling in a sample of patients with temporomandibular disorders.

OBJECTIVE: To evaluate whether therapeutic mechanisms assumed to explain the effect of cognitive behavioural therapy (CBT) concerning temporomandibular symptoms are confirmed by structural equation modelling. METHOD: Patients were randomly assigned to either an experimental group receiving CBT (N = 41) or a standard therapy control group (N = 31). Subjects were assessed before and after intervention using mediator variables hypothesized according to the CBT model, as well as outcome variables and other socio-demographic and clinical measures. RESULTS: The results confirm that the effect of treatment on pain intensity was partially mediated by distress, catastrophizing, perceived control, distraction, and mental self-control. The self-medication frequency was partially mediated by distraction. Pain interference was partially mediated by distress, distraction, and mental self-control. Reduction in the number of painful points on palpation was partially explained by distress, although in this case, there was a significant direct effect of treatment not mediated by other variables. CONCLUSIONS: The results could set the principles for the development of more efficient and effective cognitive behavioural interventions for chronic pain.