Many patients with musculoskeletal pain also suffer from a depressed mood. Catastrophizing is one process that may link depression and pain since it is a key concept in models of both problems. Earlier research has suggested that catastrophizing measures something above and beyond depression. This study tests the idea that if depressed mood and catastrophizing are separate entities then when one is absent the other should still contribute to poor outcome, and, when both are present there should be an additional adverse effect.
To this end, a prospective design, with a built-in replication from two clinical samples of patients with sub-acute pain (one from Sweden, N=373; one from Australasia, N=259), was employed. Participants were classified as to having high/low scores on measures of depression and catastrophizing. Subsequently, these classifications were studied in relation to outcome variables cross-sectionally and at follow-up.
Results showed a small to moderate correlation between catastrophizing and depression and that there are individuals with one, but not the other problem. Further, having one or the other of the entities was associated with current pain problems and outcome, while having both increased the associations substantially. The replication showed very similar results
Our data demonstrate that pain catastrophizing and heightened depressed mood have an additive and adverse effect on the impact of pain, relative to either alone. It suggests that each should be assessed in the clinic and that future research should focus on treatments specifically designed to tackle both depressed mood and catastrophizing.