For many years, scientists believed that conditions such as schizophrenia, anxiety disorders, or depression developed through a combination of numerous influences, including heredity. A new international study led by the Institute of Human Genetics at the University of Leipzig Medical Center now shows for the first time that a change in a single gene can directly cause a mental disorder. The findings were recently published in the journal Molecular Psychiatry.

The World Health Organization (WHO) reports that in 2021, nearly one in seven people worldwide was living with some form of mental illness, with anxiety disorders and depression appearing most often. These disorders usually stem from a complex mix of causes in which genetics play a major role.

Having a close relative with a mental illness is considered one of the strongest known risk factors. Earlier research generally proposed that mental disorders develop only when many genetic factors interact.

GRIN2A identified as a single-gene driver
“Our current findings indicate that GRIN2A is the first known gene that, on its own, can cause a mental illness. This distinguishes it from the polygenic causes of such disorders that have been assumed to date,” says Professor Johannes Lemke, lead author of the study and Director of the Institute of Human Genetics at the University of Leipzig Medical Center.