Making the Case

Abstract

Genome-wide association studies (GWAS) have revolutionized the field of psychiatric genetics by examining genetic variation at millions of single-nucleotide polymorphisms (SNPs) in many thousands of individual genome using microarrays. The sample sizes for these studies range from tens of thousands on up. Results to date from GWAS have called into question the validity of current diagnostic categories in psychiatry. For example, there may be some level of genetic risk that is shared across many psychiatric disorders, with the final symptom clusters of a given disorder being shaped by other genetic, epigenetic, and environmental variables. Research findings on three mental disorders are evaluated to make the case that stressful life events play a crucial role in the etiology of mental disorders. The mental disorders discussed include schizophrenia, bipolar disorder, and depression. These findings set the stage for the remainder of the book.