We conducted the comprehensive pleiotropic analysis between 4 gastrointestinal tract (GIT) diseases and 6 psychiatric (PSY) disorders from different perspectives. COLOC indicates colocalization; GSEA, gene set enrichment analysis; GWAS genome-wide association study; E-MAGMA, expression quantitative trait loci–informed multi-marker analysis of GenoMic annotation (MAGMA); H-MAGMA, Hi-C–coupled MAGMA; HyPrColoc, hypothesis prioritization for multi-trait colocalization; LD, linkage disequilibrium; PLACO, pleiotropic analysis under composite null hypothesis; SNV, single-nucleotide variation; and TWAS-JTI, transcriptome-wide association study analysis using joint-tissue imputation.