RT Journal Article SR Electronic T1 A polygenic p factor for major psychiatric disorders JF bioRxiv FD Cold Spring Harbor Laboratory SP 287987 DO 10.1101/287987 A1 Saskia Selzam A1 Jonathan R. I. Coleman A1 Avshalom Caspi A1 Terrie E. Moffitt A1 Robert Plomin YR 2018 UL http://biorxiv.org/content/early/2018/03/23/287987.abstract AB It has recently been proposed that a single dimension, called the p factor, can capture a person’s liability to mental disorder. Relevant to the p hypothesis, recent genetic research has found surprisingly high genetic correlations between pairs of psychiatric disorders. Here, for the first time we compare genetic correlations from different methods and examine their support for a genetic p factor. We tested the hypothesis of a genetic p factor by using principal component analysis on matrices of genetic correlations between major psychiatric disorders estimated by three methods – family study, Genome-wide Complex Trait Analysis, and Linkage-Disequilibrium Score Regression – and on a matrix of polygenic score correlations constructed for each individual in a UK-representative sample of 7,026 unrelated individuals. All disorders loaded on a first unrotated principal component, which accounted for 57%, 43%, 34% and 19% of the variance respectively for each method. Our results showed that all four methods provided strong support for a genetic p factor that represents the pinnacle of the hierarchical genetic architecture of psychopathology.