Researchers are increasingly discovering that psychiatric disorders that appear very different from one another may actually have overlapping genetic foundations.
In February of the previous year, scientists reported that eight separate psychiatric conditions shared common genetic factors. A December follow-up study in Nature became the largest of its kind.
Genetic Patterns Across Psychiatric Disorders
Researchers analyzed genetic data from over one million people with 14 psychiatric disorders and five million without diagnoses.
Their findings were surprising: only five shared genetic patterns appeared to explain much of the risk for developing psychiatric disorders across all 14 conditions.
One of the researchers, Andrew Grotzinger, an assistant professor of psychology and neuroscience at CU Boulder, explained that the genetic findings showed the individuals had more similarities than differences.
Understanding shared features could lead to treatments that target multiple disorders instead of separate approaches for each.
The latest research identified five distinct genetic groupings that explain most of the shared genetic risk across psychiatric conditions.
Conditions characterized by compulsive behaviors — such as anorexia nervosa, Tourette syndrome, and obsessive-compulsive disorder (OCD) — fall within the same genetic cluster.
A separate cluster includes depression, anxiety disorders, and post-traumatic stress disorder (PTSD), while substance use disorders make up a third genetic grouping.
Neurodevelopmental disorders, including autism and attention-deficit/hyperactivity disorder (ADHD), make up a fourth genetic grouping. This overlap may help explain why these conditions often share similar symptoms or frequently occur alongside one another.
Genetic Overlap Between Schizophrenia and Bipolar Disorder
One of the study’s most significant discoveries was the strong genetic connection between schizophrenia and bipolar disorder. About 70% of schizophrenia-related genetic signals are also linked to bipolar disorder, suggesting the conditions share genetic roots.
“Currently, psychiatric diagnoses are based largely on observed symptoms, and many individuals receive multiple diagnoses. This can make treatment more complicated and can be discouraging for patients,” explained Grotzinger.
The findings suggest some differently labeled disorders may share the same biological mechanisms.
This builds on 2019 research identifying 109 genes linked to eight psychiatric conditions.
In the February study, researchers examined nearly 18,000 genetic variants linked to both shared and disorder-specific genes across the eight conditions. They introduced these variants into precursor cells that develop into neurons to investigate how they influence gene activity during human brain development.
Through this approach, the team identified 683 genetic variants that altered gene regulation and then examined their effects further using neurons from developing mice.
Genetic variants that influence multiple seemingly unrelated traits or conditions are known as pleiotropic variants. The researchers found that these variants had more protein interactions and affected a wider range of brain cell types, suggesting a broader role in brain development and function.
How Shared Genetic Variants Shape Brain Development
Pleiotropic variants were also found to influence regulatory processes involved throughout different stages of brain development. Their effects on gene networks and biological pathways may explain why the same genetic changes contribute to multiple psychiatric conditions.
“Pleiotropy has traditionally been considered a complication because it makes psychiatric disorders more difficult to categorize,” said University of North Carolina geneticist Hyejung Won, lead author of the February study published in Cell.
Understanding pleiotropy could enable treatments targeting shared pathways across multiple psychiatric conditions.
Taken together, these findings suggest that the future of psychiatric diagnosis and treatment could be fundamentally different from current approaches.
With nearly 1 billion people affected by mental health conditions, these advances could transform how disorders are understood and treated.
Read the original article on: sciencealert
Read more:Mushrooms causing tiny human hallucinations contain no psychedelics