Is the course of brain development in schizophrenia delayed? Evidence fromonsets in adolescence

A degree of ventricular enlargement, together with a reduction of total cor tical mass and loss of asymmetry is reported in schizophrenia, but the mean ing is obscure. These changes may reflect an anomaly of brain development. Brain structure was assessed on a 1.5-Tesla MRI scan in a series of 29 adol escents at the rime of a first episode of schizophrenia and compared with 1 5 adolescents with other serious psychiatric disturbance (mostly psychotic) and 20 normal adolescent controls. The age at scan ranged between 13 and 2 0 years. In the adolescents with a diagnosis of schizophrenia, total brain volume increased with age in a way that differed significantly (p=0.007) fr om that seen in patients with other psychiatric disturbance and normal cont rols. Thus, brain growth, as assessed by this index, had reached a plateau in the control group by the age of 13 years, but this was not true of patie nts with schizophrenia. The measure that most clearly distinguished the gro ups (p<0.001 after co-varying for height and sex) was the volume of the lef t lateral ventricle - the ventricle was significantly larger in patients wi th schizophrenic illness: and ventricular size increased with age to a grea ter extent in the patient group, although not significantly so, than in nor mal controls. Thus, aspects of brain growth are delayed in patients with ea rly onset schizophrenia, and the greatest severity of illness is reflected in a component of growth that is lateralized to the dominant hemisphere. In dividuals who develop serious psychiatric illness, including schizophrenia, represent a fraction of the population in whom a component of the relative development of the cerebral hemispheres occurs late. (C) 1999 Elsevier Sci ence B.V. All rights reserved.