Genetic and environmental risk factors for chronic pain
They found that heritability accounted for 38.4% of the variation in chronic pain risk, and that shared environment with spouses accounted for 18.7% of the variation in susceptibility to chronic pain. They also found that chronic pain was correlated with depression. Finally, McIntosh and colleagues found evidence that polygenic risk contributes to chronic pain and MDD. Data from two independent genome wide association studies, Pfizer-23andMe and the Psychiatric Genomics Consortium Major Depressive Disorder Working Group, suggested that chronic pain risk arises through the combined effect of many different genetic risk factors and that the cumulative effects of genetic risk factors for depression increased an individual's chance of having chronic pain. The researchers note that assortative mating (choosing a spouse who is similar to oneself) may be responsible for some of the spousal effects, and that these associations do not identify mechanisms through which the genes might be