Brain imaging in normal and abnormal brain development: new perspectives for child psychiatry

Abstract

Non-invasive brain imaging permits the study of normal and abnormal brain development in childhood and adolescence. This paper summarizes current knowledge of brain development for healthy adolescents and for patients with childhood-onset schizophrenia (COS), a rare form of the disorder. The implications of these findings are explored. Cross-sectional and longitudinal brain magnetic resonance imaging (MRI) studies are reviewed. The pattern and temporal characteristics of anatomic brain MRI in adult-onset schizophrenia (AOS) and COS are reviewed, and discussed in terms of normal brain development and candidate mechanisms. A consistent, abnormal pattern of childhood brain development is found for COS. Normal children show non-linear regionally specific changes in gray matter volume and linear increase in white matter. COS children have smaller brain volumes due to a 10% decrease in cortical gray matter with white matter sparing. Moreover, there is a progressive loss of regional gray matter particularly in parietal, frontal and temporal regions during adolescence that is more striking for COS than that seen for AOS. In COS, developmental data are consistent with models of time limited diagnostically specific abnormalities of synaptic and dendritic production and pruning. Selected human postmortem brain and developmental animal studies relevant to such models are reviewed.