Imaging Genetics and Psychiatry

Many important psychiatric disorders have a strong hereditary component, posing the problem of characterizing the biological mechanisms translating from the genetic level to that of complex social and behavioral abnormalities. The new field of imaging genetics uses neuroimaging methods to assess the impact of genetic variation on the human brain. Ideally, several imaging methods are used in conjunction to achieve an optimal characterization of structural-functional parameters in large groups of carefully screened individuals, whose genotype is then statistically related to these data across subjects. Imaging genetics is therefore a form of genetic association study. Although this approach is still relatively novel, the emerging literature shows that it can be used to identify neural processes involved in mediating the effect of genetic polymorphisms on psychiatric disease risk, contributing to the understanding of the pathophysiology of these complex disorders. We illustrate this approach using selected examples from genes involved in risk for schizophrenia (COMT, GRM3, DISC1, and G72), Alzheimer’s disease (APOE4), and depression, anxiety, and violence (5-HTTLPR and MAOA). Improved mechanistic understanding of psychiatric disease provides novel targets for future therapeutic interventions and may contribute to a more accurate biologically based nosology.