Summary: A new study finds that people whose partners have depression are at greater risk of developing chronic pain.
Partners of people with depression are more likely to suffer from chronic pain, new research from the University of Edinburgh shows.
Researchers report that chronic pain and depression share both genetic and environmental causes. Some risk factors are inherited, while others arise from shared environments experienced by partners or spouses. The findings provide fresh insight into why chronic pain and depression often occur together and may eventually help improve diagnosis and treatment.
The research team analyzed health and genetic information from more than 100,000 participants drawn from large, nationwide studies. Using data from Generation Scotland and the UK Biobank, the investigators examined participants’ genetic profiles alongside detailed accounts of pain and depressive symptoms.
The investigators report that chronic pain is moderately heritable but also strongly influenced by factors shared between partners. In particular, having a partner with depression was associated with a substantially higher likelihood of experiencing chronic pain oneself. The team found significant overlap between the genetic and environmental risk factors for chronic pain and those for major depressive disorder (MDD).
Professor Andrew McIntosh, Chair of Biological Psychiatry at the University of Edinburgh, commented that the research encourages a broader view of how physical and mental illnesses interact: “We hope our research will encourage people to think about the relationship between chronic pain and depression and whether physical and mental illnesses are as separate as some believe.”
Study design and key findings
The study used family-based mixed-model analyses to estimate how much of chronic pain risk is explained by inherited genetic factors and how much is explained by environmental influences shared by families, households, siblings, or spouses. Analyses were conducted in Generation Scotland: Scottish Family Health Study (GS:SFHS) with 23,960 participants and were replicated using data from the UK Biobank cohort (over 112,000 participants with genotyping and phenotypic data).
Key findings include:
- Chronic pain showed moderate heritability, with an estimated heritability of 38.4% (95% CI 33.6% to 43.9%).
- Concordance of chronic pain in spouses explained a meaningful proportion of the variance (18.7%, 95% CI 9.5% to 25.1%), indicating substantial shared environmental effects between partners.
- Chronic pain and depression were positively correlated (ρ = 0.13, 95% CI 0.11 to 0.15, p = 2.72×10−68), and they showed a notable genetic correlation (genetic correlation = 0.51, 95% CI 0.40 to 0.62, p = 8.24×10−19), suggesting overlapping genetic risk.
- Polygenic risk profiles derived from independent genome-wide association studies (GWAS) for pain were associated with chronic pain in both cohorts. Genomic risk for major depressive disorder also predicted chronic pain across datasets.
The authors note limitations including the possibility that spouse effects may partly reflect assortative mating (people choosing similar partners) and that polygenic risk score effect sizes remain modest.
Conclusions
The study concludes that both inherited genetic factors and environmental influences shared within partnerships contribute substantially to individual risk for chronic pain. Chronic pain has a polygenic architecture, shows genetic overlap with major depressive disorder, and is influenced by a partner’s mental health status. These results underline the importance of considering both genetic predisposition and shared environmental exposures when assessing chronic pain risk and designing interventions.
About the research
Source: University of Edinburgh. The study was a collaboration involving researchers from the Universities of Edinburgh, Dundee, Aberdeen and Glasgow and was published in PLOS Medicine. The research used data from Generation Scotland and the UK Biobank and received funding from Wellcome.
Original research: “Genetic and Environmental Risk for Chronic Pain and the Contribution of Risk Variants for Major Depressive Disorder: A Family-Based Mixed-Model Analysis.” Authors include Andrew M. McIntosh, Lynsey S. Hall, Yanni Zeng, Mark J. Adams and colleagues. Published online August 16, 2016. DOI: 10.1371/journal.pmed.1002090.