Genetic predisposition to loneliness increases schizophrenia and depression risk through inflammatory pathways: a Mendelian randomization study

The primary objective of this study is to evaluate whether inflammatory biomarkers mediate the causal effect between loneliness (perceived social isolation) and severe mental illness (SMI), including schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BD). Results support the role of inflammatory signaling pathways as potential mediators linking loneliness to increased psychiatric risk. This repository contains all formatted datasets, analytic outputs, and reproducible scripts used for two-sample Mendelian randomization (MR), multivariable Mendelian randomization (MVMR), and Bayesian colocalization analyses. All analyses were conducted using publicly available GWAS, eQTL, and pQTL summary statistics. No individual-level data are included.