A landmark study published in Nature has identified five genetic signatures shared across 14 distinct psychiatric disorders, suggesting these conditions have more biological similarities than previously understood. The research, led by scientists from the University of Colorado Boulder, Harvard, and Mass General Brigham, analyzed DNA data from more than 1 million individuals diagnosed with at least one psychiatric disorder and 5 million without any diagnoses.
The study discovered that five underlying “genomic factors” involving 238 genetic variants account for the majority of genetic differences between those with a particular disorder and those without. These factors organize psychiatric conditions into five categories: compulsive disorders such as anorexia nervosa, Tourette disorder, and obsessive-compulsive disorder; internalizing conditions including depression, anxiety, and post-traumatic stress disorder; substance use disorders; neurodevelopmental conditions such as autism and attention-deficit/hyperactivity disorder; and a fifth category linking bipolar disorder and schizophrenia. Notably, the research found that 70 percent of the genetic signal in schizophrenia is also present in bipolar disorder, despite the field historically viewing them as distinct conditions.
The findings identify specific biological pathways underlying these groupings. In bipolar disorder and schizophrenia, genes influencing excitatory neurons—which transmit signals across other neurons—tend to be over-expressed. In internalizing disorders like depression and anxiety, variants in genes controlling oligodendrocytes, specialized cells that maintain and protect the brain’s wiring, were common. Some shared genetic factors appear to influence brain development during fetal stages, while others may have greater impact later in adult life.
According to Andrew Grotzinger, assistant professor at CU Boulder, the findings suggest that conditions currently given different names may actually be driven by the same biological processes. As he noted, “By identifying what is shared across these disorders, we can hopefully come up with strategies to target them in a different way that doesn’t require four separate pills or four separate psychotherapy interventions.” Jordan Smoller, director of the Psychiatric and Neurodevelopmental Genetics Unit at Mass General Hospital, said the findings provide “valuable clues for advancing our understanding and treatment of mental illness with greater precision.”
This article is an AI-assisted summary. All facts and figures are drawn from the original report: https://news.harvard.edu/gazette/story/2025/12/new-research-finds-5-genetic-signatures-shared-by-14-psychiatric-disorders/