Schizophrenia and Bipolar Disorder as Primarily Genetic Illnesses: It Ain't Necessarily So (Homage to George Gershwin)

Steven Hyman (1999), former director of NIMH and currently Provost of Harvard University, in discussing the role of molecular biology and neurogenetics in research on mental disorders (“Looking to the future: The role of genetics and molecular biology in research on mental illness” in Psychiatry in the New Millennium edited in 1999 by Sidney Weissman, Melvin Sabshin and Harold Eist for the American Psychiatric Press), proposed:

“Scientific and technological developments in genetics and molecular biology have been rapid and profound during the last 15 years; as a result, the use of molecular tools should drive a great deal of progress in research on mental disorders and their treatments as we approach the new millennium. At the same time, however, it is critical to recognize that molecular approaches cannot achieve the core goals of psychiatric research by themselves. Understanding mental disorders, discovering more effective treatments, and possessing – eventually -- effective approaches to prevention demand that what we learn from molecular biology and genetics be put in the context of what we are also learning at higher levels of integration; for example, from neuroscience and behavioral science...the pathophysiology of mental disorders depends on the complex interaction of genetic (“bottom-up”) factors and environmental (“top-down”) factors affecting the development and subsequent function of the brain, and hence our mental lives and behavior. The eventual discovery of genes that confer vulnerability to (or that protect against) mental disorders will not supersede research on environmental factors [sadly, this call for equal inclusion of sociocultural-environmental research has not been heeded by many financing bodies]; indeed, studies of the inheritance of mental disorders, most notably studies of monozygotic twins (i.e., twins with identical genomes), have demonstrated that genes confer vulnerability but not the certainty of mental disorder. Genes collaborate with environmental “second hits” to produce illness per se, as well as the individual’s particular pattern of illness. Thus the identification of disease vulnerability genes will provide important clues not only to neuroscientists trying to understand pathophysiology [as well as brain function], but also to behavioral scientists and others trying to identify environmental factors that lead to illness or resilience” (pp. 97-98).

Brian Koehler PhD
New York University