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T. Benz1,2, F. Angst1, S. Lehmann1, S. Wagner1, B. Simmen3, P. Sandor1, M. Gengenbacher1, J. Angst4
1RehaClinic, Research Department, Bad Zurzach, Switzerland, 2Zurich University of Applied Sciences, Institute of Physiotherapy, Winterthur, Switzerland, 3Clinic Hirslanden, Endoclinic, Zurich, Switzerland, 4Psychiatric Hospital Burghölzli, Department of Psychiatry, Psychotherapy and Psychosomatics, Zurich, Switzerland
Background: The relationship between pain and depression has stimulated research and generated a huge body of scientific literature over the years. The bulk of those research results is based on cross-sectional assessment and thresholds for pain and depression. Research data and clinical observation have led to the hypothesis that after a certain latency pain may cause depression and vice versa. This hypothesis needs to be investigated on the basis of longitudinal data.
Purpose: The aim was to quantify and to compare the associations between longitudinal, changes in continuously measured pain and depression in different chronic pain conditions.
Methods: Data were retrieved from 6 naturalistic, observational cohort studies. From baseline to the 6-month follow-up, the score changes on the Short Form (36) Health Survey (SF-36) bodily pain (pain) and the SF-36 mental health (depression) scales (0=worst, 100=best) were quantified, using partial correlations obtained by multivariate regression. Adjustment was performed by age, living alone/with partner, education level, number of comorbidities, baseline pain and baseline depression.
Results: Stronger associations were found between changes in levels of pain and depression for neck pain after whiplash (n=103, mean baseline pain=21.4, mean baseline depression=52.5, adjusted correlation r=0.515), knee osteoarthritis (n=177, 25.4, 64.2, r=0.502), low back pain (n=134, 19.0, 49.4, r=0.495), and fibromyalgia (n=125, 16.8, 43.2, r=0.467) than for lower limb lipedema (n=68, 40.2, 62.6, r=0.452) and shoulder osteoarthritis (n=153, 35.0, 76.4, r=0.292). Those correlations were somewhat correlated to baseline pain (rank r=–0.429) and baseline depression (rank r=–0.314).
Conclusion(s): Moderate associations between changes in pain and depression levels were demonstrated across 5 of 6 different chronic pain conditions, in which relatively high pain levels persisted after conservative therapy. The associations between pain change and depression change tended to be stronger if pain and depression were worse at baseline. These two observed dose-response relationships are indicative of a certain degree of causal interference.
Implications: Our results suggest that relieving pain may lead to the relief of depression and vice versa, which should be further substantiated by specific intervention studies.
Funding, acknowledgements: There are no sources of funding to declare.
Keywords: Pain and Depression, Longitudinal change, Association, Correlation, Causality
Topic: Pain & pain management
Did this work require ethics approval? Yes
Institution: ethics committee of Aarau, Canton Aargau, Switzerland
Committee: ethics committee of Aarau, Canton Aargau, Switzerland
Ethics number: EK AG 2008/026
All authors, affiliations and abstracts have been published as submitted.
