Evidence for indirect effects of pain catastrophizing on clinical pain among myofascial temporomandibular disorder participants: the mediating role of sleep disturbance.

Sleep disturbance and pain catastrophizing are important mediators of the chronic pain experience. To date, these factors have not been considered concurrently despite compelling theoretical rationale to do so. In the present study, we examined whether pain catastrophizing not only has direct effects on clinical pain and pain-related interference, but also indirect effects through its association with sleep disturbance. We evaluated this hypothesis using a cohort (n=214) of myofascial temporomandibular disorder participants using a statistical bootstrapping technique recommended for tests of indirect effects. Results suggested that pain catastrophizing was associated with greater sleep disturbance, and that a significant portion of variance in clinical pain severity and pain-related interference attributable to pain catastrophizing was mediated by sleep disturbance. Supplementary analyses revealed that the rumination component of catastrophizing seemed to be indirectly related to clinical outcomes through sleep disturbance. No evidence for indirect effects was observed for helplessness and magnification components. These results suggest that rumination about pain may contribute to clinical pain indirectly through alterations in sleep. Prospective studies are needed to examine lagged associations between these constructs. These findings have important theoretical and clinical implications. Critically, interventions that reduce pain catastrophizing may concurrently improve sleep and clinical pain.