Five Psychiatric Disorders Share Genetic Risk Factors

Five different psychiatric illnesses share a handful of genetic risk factors, report researchers in The Lancet.

Four DNA mutations were discovered in the genomes of people who had at least one of five distinct disorders: attention deficit-hyperactivity disorder, autism, bipolar disorder, major depressive disorder and schizophrenia. The findings feed into a broader goal of “moving beyond descriptive syndromes in psychiatry and towards a [classification] informed by disease cause,” write the researchers in their report.

Two of the genetic variants are not linked to any particular gene function, but the other two are found in genes involved in controlling the flow of calcium in neurons, which regulates the brain cells’ activity. There’s a chance, then, that one kind of drug could treat multiple disorders. As lead study author Jordan Smoller of Harvard Medical School and Massachusetts General Hospital told the New York Times:

“The calcium channel findings suggest that perhaps—and this is a big if —treatments to affect calcium channel functioning might have effects across a range of disorders,”

The team examined the genomes of 33,332 patients with at least one of the disorders and compared them to the genomes of 27,888 people without, making the project the largest ever genetic study of psychiatric illness, say the researchers.

Their results suggest that same mutation may lead to different disorders in different people, depending on other factors. As Judith Rapoport, chief of the child psychiatry branch at the National Institute of Mental Health, told the Boston Globe:

“There’s a sense in psychiatry there may be some very common genetic variants that, let’s say hypothetically, very early on affect very early brain development. . . . Then, maybe environment, or interactions with other genes” causes a particular illness to develop.

The results point to a future were quantitative genetic data could be incorporated into qualitative clinical diagnoses. In an accompanying commentary, psychiatrist researchers Alessandro Serretti and Chiara Fabbri from the University of Bologna in Italy write “the present study might contribute to future [classification] systems, which could be based not only on statistically determined clinical categories, but also on biological pathogenic factors that are pivotal to the identification of suitable treatments.”