NRG1 and psychotic disorder: Ventricular enlargement is a major neuroanatomical biomarker in schizophrenia.36 It has been linked to NRG1 risk variants in first-episode schizophrenia patients37 and in individuals at high risk for psychosis.38 We reported enlarged lateral ventricles in transgenic mice with CRD-NRG1 overexpression.14 Here, we confirm increased ventricular size in T-Nrg1 mice, demonstrating ventricular enlargement as a specific outcome of hyperactive CRD-NRG1 signaling.