Chapter 3.Genomics in Geriatric Psychiatry

The flow of events leading from variation in a gene sequence to the development of the various cognitive, behavioral, and emotional criteria that encompass psychiatric disorders of later life is not straightforward. However, the understanding of these processes is well under way and has the potential to significantly influence the practice of geriatric psychiatry in the twenty-first century. The completion of the Human Genome Project a decade ago marked a milestone in the field of genomics. Since then, the field has rapidly moved forward, with the first genomic mapping of a living human followed by the more recent availability of direct-to-consumer genome sequencing. Personalized genome sequencing (Levy et al. 2007) is a reality that will have a profound impact on the field. Family, twin, and adoption studies have demonstrated robust genetic influences in schizophrenia, bipolar disorders, and Alzheimer’s disease (AD), and conventional and newer approaches have advanced the understanding of the specific genetic components of these disorders. In this chapter, we have attempted to 1) summarize key advances in genomic science, 2) provide an introduction to the growing field of genomic medicine (especially as it relates to genetic testing), and 3) review the current state of understanding of genetics of mental disorders of aging and later life.