Delayed White Matter Growth Trajectory in Young Nonpsychotic Siblings of Patients With Childhood-Onset Schizophrenia

Context Nonpsychotic siblings of patients with childhood-onset schizophrenia (COS) share cortical gray matter abnormalities with their probands at an early age; these normalize by the time the siblings are aged 18 years, suggesting that the gray matter abnormalities in schizophrenia could be an age-specific endophenotype. Patients with COS also show significant white matter (WM) growth deficits, which have not yet been explored in nonpsychotic siblings. Objective To study WM growth differences in nonpsychotic siblings of patients with COS. Design Longitudinal (5-year) anatomic magnetic resonance imaging study mapping WM growth using a novel tensor-based morphometry analysis. Setting National Institutes of Health Clinical Center, Bethesda, Maryland. Participants Forty-nine healthy siblings of patients with COS (mean [SD] age, 16.1 [5.3] years; 19 male, 30 female) and 57 healthy persons serving as controls (age, 16.9 [5.3] years; 29 male, 28 female). Intervention Magnetic resonance imaging. Main Outcome Measure White matter growth rates. Results We compared the WM growth rates in 3 age ranges. In the youngest age group (7 to Conclusions In this first longitudinal study of nonpsychotic siblings of patients with COS, the siblings showed early WM growth deficits, which normalized with age. As reported before for gray matter, WM growth may also be an age-specific endophenotype that shows compensatory normalization with age.