Study objectives: One theoretical model suggests a pathway between pain and the development of depression through sleep problems. Here, we prospectively test the hypothesis that incident sleep problems, in those with persistent pain, increase risk of new onset probable depression, and investigate the role of "pain that interferes with daily life" (pain interference) on this pathway.
Design: Prospective cohort study.
Setting: Community based population study within UK.
Participants: Participants with persistent pain nested within a larger longitudinal community study.
Measurements: Participants were mailed health questionnaires at baseline (time 1) with follow-up at 3 years (time 2) and 6 years from baseline (time 3). Questionnaires at baseline and at follow up contained measures of sleep problems (Jenkins Sleep Questionnaire), depressive symptoms (Hospital Anxiety and Depressive Scale), and pain interference.
Results: In total, 2,622 participants returned health questionnaires at all time points and indicated the presence of pain at each time point. After adjustment for age, gender, marital status, employment status, alcohol intake, smoking status, and body mass index, having a new period of sleep problems at year 3 more than trebled the risk of a new period of probable depression at year 6 (relative risk 3.47, 95% CI 1.97 to 6.03). Mediation analysis showed that pain interference played a significant but relatively minor role in the pathway.
Conclusion: Clinicians treating patients with persistent pain may wish to consider options that involve addressing the prevention or treatment of sleep problems, in addition to their primary focus of pain management.
Keywords: Persistent pain; cohort; depression; pain interference; sleep problems.