Neuroimaging Studies in Psychotic Disorders

Abstract

Neuroimaging techniques yield not only structural but also physiological information, of particular interest in the scientific and clinical investigations of psychiatric disorders. Of note, the development of new imaging tools in the last two decades, such as high-resolution three-dimensional magnetic resonance imaging, allows to accurately examine small brain structures and their regional function. The combination of conventional magnetic resonance imaging (MRI) studies with functional studies has improved the detection of abnormalities in blood flow, metabolism, and neurotransmitter receptor function. It has the potential of providing a better-integrated model to understand molecular biology and also has clinical and treatment applications. Structural imaging studies have confirmed the presence of cortical abnormalities in chronic schizophrenia, especially in the prefrontal and temporal cortex. In early episodes of psychosis in adolescents, a loss of gray matter has also been observed in the frontal, temporal, and parietal lobes. With magnetic resonance spectroscopy, the most frequent abnormality observed in chronic patients was a decrease of the N-acetylaspartate/creatine ratio in the hippocampus and in the prefrontal region. Diffusion tensor imaging studies in people with adult-onset schizophrenia have generally reported reductions in fractional anisotropy in areas corresponding to the major fasciculi connecting the frontal, temporal, and parietal cortices. Compared with their respective controls, individuals with adolescent-onset schizophrenia showed decreased fractional anisotropy in the parietal regions. In this chapter, we review structural, functional, and metabolic brain changes in patients with psychotic disorders, using magnetic resonance imaging.