Imaging as a tool in exploring the neurodevelopment and genetics of schizophrenia.

Neuroimaging has enabled us to address questions about the timing and origin of brain abnormalities in schizophrenia. First episode and longitudinal computed tomography (CT) and magnetic resonance imaging (MRI) studies of schizophrenic patients have shown that the brain abnormalities are present at onset of psychosis and are non-progressive. Such findings support the idea that schizophrenia is a developmental rather than a degenerative condition. Furthermore, the presence of ventriculomegaly and diminished hemispheric asymmetry in familial schizophrenics and in those of their relatives who appear to be transmitting the disorder, implies involvement of the genes controlling neurodevelopment. However, genetic factors do not fully account for the development of schizophrenia; early environmental insults such as obstetric complications are also important and may interact with genetic predisposition. Brain development continues postnatally and profound maturational events also occur in adolescence and early adulthood. Magnetic resonance spectroscopy (MRS) studies allow the investigation of the developmental biochemistry of the living brain and are being used to explore the role of maturational brain events in determining the onset of psychosis.