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BOSTON — In a landmark study that could fundamentally reshape the landscape of mental healthcare, researchers have uncovered evidence that most psychiatric disorders are not isolated islands of illness but are deeply interconnected by a shared genetic architecture.
The analysis, published Dec. 10 in the journal Nature, examined DNA data from over 6 million individuals, making it the largest and most detailed genomic study of its kind to date. The international team found that 14 different psychiatric conditions—ranging from depression and anxiety to schizophrenia and anorexia—cluster into five distinct “genomic families.” These findings provide a biological explanation for why more than half of people diagnosed with one mental health condition will eventually be diagnosed with a second or third in their lifetime.
“This work provides the best evidence yet that there may be things that we are currently giving different names to that are actually driven by the same biological processes,” said corresponding author Andrew Grotzinger, PhD, assistant professor of psychology and neuroscience at the University of Colorado Boulder, in a statement released with the study.
Breaking Down the Five ‘Genomic Families’
For decades, psychiatry has relied on symptom-based diagnoses. A patient is diagnosed with “Major Depressive Disorder” if they meet specific behavioral criteria, and “Generalised Anxiety Disorder” if they meet others. However, the new research suggests that these symptoms often spring from the same genetic well.
The researchers identified five underlying “genomic factors” that account for nearly two-thirds of the genetic differences between those with a psychiatric disorder and those without. These factors grouped the 14 conditions into the following families:
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Internalizing Disorders: Including major depression, anxiety disorders, and post-traumatic stress disorder (PTSD).
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Schizophrenia and Bipolar Disorder: Despite being historically treated as distinct, the study found that 70% of the genetic signal associated with schizophrenia is shared with bipolar disorder.
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Compulsive Disorders: Grouping obsessive-compulsive disorder (OCD), anorexia nervosa, and Tourette disorder.
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Neurodevelopmental Disorders: Including autism spectrum disorder (ASD) and ADHD.
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Substance Use Disorders: Covering alcohol, cannabis, tobacco, and opioid use disorders.
In the case of “internalizing disorders” like depression and anxiety, the overlap was even more striking, with approximately 90% of the genetic risk estimated to be shared across the cluster.
A Look Inside the Brain’s Wiring
The study did more than just find correlations; it identified where in the brain these shared genes are most active. By integrating genetic data with maps of brain tissue, the researchers discovered that different genomic families impact different types of brain cells.
For instance, the genetic variants shared by schizophrenia and bipolar disorder were highly active in excitatory neurons—the cells responsible for sending signals across the brain. Conversely, the “internalizing” cluster of depression and anxiety was more closely tied to oligodendrocytes, specialized cells that maintain the brain’s “insulation” or wiring infrastructure.
“By identifying what is shared across these disorders, we can hopefully come up with strategies to target them in a different way,” Grotzinger explained. This could eventually lead to treatments that address the underlying biological root rather than requiring multiple separate medications for different symptoms.
Expert Perspective: Why This Matters Now
While the findings are groundbreaking, experts emphasize that they are a roadmap for the future rather than a guide for today’s clinical practice.
“The results help explain why comorbidity is the rule rather than the exception in psychiatry,” said Jordan Smoller, MD, Director of the Center for Precision Psychiatry at Massachusetts General Hospital and co-corresponding author of the study. He noted that the research clarifies why patients often move between different diagnoses over time as their symptoms evolve.
However, Dr. Smoller also cautioned that these findings are not yet ready to guide genetic testing or prescribing decisions in a doctor’s office. “In the near term, these findings are not intended to change clinical practice directly,” he told Medscape Medical News. “The shared genetic factors identified must be linked more directly to clinically meaningful outcomes, such as treatment response and functional recovery.”
Limitations and the Road Ahead
Despite the study’s massive scale, it has limitations. The primary analysis was conducted using data from individuals of European ancestry. Researchers acknowledged that larger, more diverse datasets are needed to ensure these findings apply to all populations.
Additionally, genetics is only one piece of the puzzle. Environmental factors, lived experiences, and trauma also play critical roles in the development of mental illness. The study aims to complement, not replace, the understanding of how environment and biology interact.
For patients and families, the research offers a sense of validation. It suggests that having multiple diagnoses is not a sign of a “uniquely broken” brain, but rather a reflection of a shared biological vulnerability that modern science is finally beginning to map.
Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.
References
Primary Study
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Grotzinger, A. D., Werme, J., Peyrot, W. J., et al. (2025). Mapping the genetic landscape across 14 psychiatric disorders. Nature. DOI: 10.1038/s41586-025-09820-3
