Harmonization of transdiagnostic psychiatric phenotypes across a large multi-site study reveals high burden of neuropsychiatric multimorbidity in 16p11.2 and 22q11.2 copy number variant carriers.

Modern psychiatric research is increasingly collaborative, but significant differences in recruitment and assessment methods across cohorts present major methodological challenges when integrating data. The Core Psychiatric Phenotype Summary (C2PS) tool was developed to harmonize data on psychiatric/neurodevelopmental diagnoses and subthreshold symptoms from multiple sources. Demonstrating its reliability, and breadth and depth, we report findings in the largest cohort to date of individuals with reciprocal copy number variants (CNVs) at 22q11.2 or 16p11.2, collected across 14 international si