Psychiatric genetics

Psychiatric genetics is a subfield of behavioral neurogenetics and behavioral genetics which studies the role of genetics in the development of mental disorders (such as alcoholism, schizophrenia, bipolar disorder, and autism). The basic principle behind psychiatric genetics is that genetic polymorphisms (as indicated by linkage to e.g. a single nucleotide polymorphism) are part of the causation of psychiatric disorders. Psychiatric genetics is a somewhat new name for the old question, "Are behavioral and psychological conditions and deviations inherited?". The goal of psychiatric genetics is to better understand the causes of psychiatric disorders, to use that knowledge to improve treatment methods, and possibly also to develop personalized treatments based on genetic profiles (see pharmacogenomics). In other words, the goal is to transform parts of psychiatry into a neuroscience-based discipline. Recent advances in molecular biology allowed for the identification of hundreds of common and rare genetic variations that contribute to psychiatric disorders. Research on psychiatric genetics began in the late nineteenth century with Francis Galton (a founder of psychiatric genetics) who was motivated by the work of Charles Darwin and his concept of desegregation. These methods of study later improved due to the development of more advanced clinical, epidemiological, and biometrical research tools. Better research tools were the precursor to the ability to perform valid family, twin, and adoption studies. Researchers learned that genes influence how these disorders manifest and that they tend to aggregate in families. Most psychiatric disorders are highly heritable; the estimated heritability for bipolar disorder, schizophrenia, and autism (80% or higher) is much higher than that of diseases like breast cancer and Parkinson disease. Having a close family member affected by a mental illness is the largest known risk factor, to date. However, linkage analysis and genome-wide association studies have found few reproducible risk factors.