Having a high polygenic risk score for depression, being single, and having a small social network are all associated with a high risk of depression, according to a study in the American Journal of Geriatric Psychiatry.
A total of 2279 people ≥55 years of age from the ongoing Longitudinal Aging Study of Amsterdam who had available genotyping data over a mean follow-up of 15 years were included in this study. The researchers developed 2 risk scores for depression by calculating polygenic risk scores that were based on 23,032 single nucleotide polymorphisms associated with major depression. Questionnaires were used to assess participants’ partner status, social network size, as well as received and given emotional support. The Center for Epidemiologic Studies Depression Scale was used to assess for depressive symptoms.
Participants with higher polygenic risk scores for depression had higher depressive symptoms (B, 0.053; 95% CI, 0.023-0.083; Z, 3.5; P =.0005). Factors associated with less depressive symptoms included having a partner (B, -0.325; 95% CI, -0.483 to -0.166; Z, 4.01; P <.0001) and having a larger social network size (B, -0.008; 95% CI, -0.010 to -0.005; Z, 7.49; P <.0001). There was no association between depressive symptoms and received emotional support (B, 0.001; 95% CI, -0.002-0.003; Z, 0.33; P =.74) and given emotional support (B, -0.003; 95% CI, -0.006-0.000; Z, 1.69; P =.09).
Additionally, the study found no gene-environment interaction between polygenic risk scores for depression and partner status (B, -0.014; 95% CI, -0.077-0.049; Z, 0.43; P =.67), social network size (B, -0.001; 95% CI, -0.003-0.002; Z, 0.49; P =.62), received emotional support (B, 0.001; 95% CI, -0.002-0.003; Z, 0.58; P =.56), or given emotional support (B, 0.001; 95% CI, -0.002-0.004; Z, 0.52; P =.60).
A limitation of the study was that only people with European ancestry were included, which may reduce the generalizability of the findings.
Since the researchers did not identify any specific subgroup that could potentially benefit from additional interventions that can boost social functioning, they suggested that “such interventions should be encouraged in the general population of older adults regardless of the genetic liability for depression.”
Stringa N, Milaneschi Y, Schoor NMV, et al. Genetic liability for depression, social factors and their interaction effect in depressive symptoms and depression over time in older adults [published online March 8, 2020]. Am J Geriatr Psychiatry. doi: 10.1016/j.jagp.2020.02.011.