Impact of pain and catastrophizing on the long-term course of depression in the general population: the HUNT pain study.

Pain and depression are episodic conditions that might take a chronic course. They are clearly related, but information on how they influence each other in the process of chronification is limited. Pain catastrophizing is hypothesized to play a role in the development of depression and chronic pain, but few longitudinal studies have investigated their association over a longer term. In this study, a random cohort from the general population (n = 4764) answered questions about pain, catastrophizing, and depression at 5 assessments in yearly intervals. Linear mixed models showed that within persons, increases in pain intensity and catastrophizing were independently associated with increases in depressive symptoms {mean change = -1.12, 95% confidence interval (CI) [-1.32 to -0.91] and -1.29, 95% CI [-1.52 to -1.05], respectively}. In prospective analyses restricted to individuals without depression above cutoff at baseline, chronic pain increased the risk of endorsing depression over the following 4 years (odds ratio = 2.01, 95% CI [1.71-2.37]). Seven percent showed a chronic course of depression, as indicated by scores above cutoff on at least 3 of 5 assessments. The number of years lived with chronic pain was associated with a chronic course of depression, with odds ratios increasing from 1.55 (95% CI [0.87-2.91]) to 14.19 (95% CI [8.99-22.41]) when reporting chronic pain on 2 vs 5 assessments compared with none. The results suggest that when pain intensity or catastrophizing change, depressive symptoms change in the same direction. When pain and catastrophizing become chronic, they seem to be mutually reinforcing determinants for chronic depression.