For a study, researchers sought to investigate the pleiotropy of psychiatric and immune-related features and risk variables of predicted significance.

The genetic association analysis was carried out between July 10, 2020, and January 15, 2022. GWA statistics were utilized in analyses of 14 psychiatric characteristics, 13 immune-related phenotypes, such as allergy, autoimmune, and inflammatory illnesses, and 15 risk variables linked to health-associated behaviors, social determinants of health, and stress response. Mendelian randomization (MR) with sensitivity analysis and multivariable correction for genetic connections of third variables was used to identify genetically associated psychiatric-immune couples. The false discovery rate correction (Q value<.05) was used for each analysis. Estimates of genetic correlations and MR associations with SEs and P values. A data-driven method was utilized, with no pre-planned hypotheses tested.

There were 44 genetically associated psychiatric-immune pairings found, with 31 positive associations (most frequently including asthma, Crohn’s disease, hypothyroidism, and ulcerative colitis) and 13 negative correlations (most consistently involving allergic rhinitis and type 1 diabetes). For psychiatric traits, correlations with third factors were very high. In addition, MR identified 7 associations of psychiatric phenotypes with immune-related phenotypes that were robust to multivariable adjustment, including the positive association of the psychiatric cross-disorder phenotype with asthma (odds ratio [OR], 1.04; 95% CI, 1.02-1.06), Crohn disease (OR, 1.09; 95% CI, 1.05-1.14), and ulcerative colitis (OR, 1.09; 95% CI, 1.05-1.14); major depression with asthma (OR, 1.25; 95% CI, 1.13-1.37); schizophrenia with Crohn disease (OR, 1.12; 95% CI, 1.05-1.18) and ulcerative colitis (OR, 1.14; 95% CI, 1.07-1.21); and a negative association of risk tolerance with allergic rhinitis (OR, 0.77; 95% CI, 0.67-0.92). 

According to the findings of the genetic association study, genetic liability for psychiatric disorders is associated with liability for several immune disorders, implying that vertical pleiotropy related to behavioral traits (or third correlated variables) contributes to clinical associations observed in population-scale data.