We formally modeled this genetic covariance structure in Genomic SEM13, finding that a four correlated factors model fit the data well (Fig. 1b). Factor 1 consists of disorders characterized largely by compulsive behaviors (AN, OCD, TS). Factor 2 is characterized by disorders that may have psychotic features (SCZ, BIP). Factor 3 is characterized primarily by childhood-onset neurodevelopmental disorders (ADHD, AUT). Factor 4 is characterized by internalizing disorders (ANX, MDD). In line with prior evidence for a higher-order transdiagnostic “p-factor”5-7, we find that a hierarchical model also fit the genetic covariance structure well (Fig. 1c). We retained these two models—the four correlated factors model and the hierarchical factor model—to examine the utility of the genomic factors at biobehavioral, functional genomic, and molecular levels of analysis. We discuss a post-hoc bifactor model (Fig. 1d) at the end of the Results section.
