Morphological brain imaging studies on major psychoses

The first application of computed tomographic scan to the schizophrenic brain by Johnstone et al. initiated a new neuroscience research era with new perspectives on the neurobiological aspects of major psychoses. The most common paradigm in the flurry of brain imaging studies following the first report was the case-control study comparing controls and patients with major psychoses. However, some application was also made of sophisticated case-control paradigms, such as comparisons between affected and non-affected identical twins discordant for schizophrenia. Very few prospective cohort studies have been applied in this field. During the past two decades of studies, several brain morphological features have converged. Both schizophrenics and patients with affective disorders showed subtle but significant quantitative differences in brain structures compared with controls. For schizophrenia, the differences were in the lateral and third ventricles, medial temporal lobe, supratemporal gyrus, frontal lobe and such subcortical nuclei as striatum and thalamus. For affective disorders, they were in the cortical sulci, lateral ventricle, striatum, pituitary and adrenal glands. Generally, the differences were greater in schizophrenics, in males and on the left side than in patients with affective disorders, in females and on the right side. Qualitative morphological abnormalities such as T2-weighted hyperintensity were also demonstrated in elderly patients with affective disorders. For both schizophrenia and affective disorders, abnormal anatomical neurocircuit models of the respective pathophysiologies have been proposed to explain the brain multi-lesions. Some recommendations for future research in the structural brain imaging of major psychoses have also been proposed.