A large team of international scientists has made progress in solving a mystery in mental health: why so many people are diagnosed with more than one psychiatric disorder during their lives.
The study, published in the journal Nature, looked at the shared genetic causes behind 14 mental health conditions and is the most detailed research of its kind so far.
The research was led by the Cross-Disorder Working Group of the Psychiatric Genomics Consortium. The team includes top experts like Dr. Kenneth Kendler from Virginia Commonwealth University and Dr. Jordan Smoller from Harvard Medical School.
It is common for people with one mental health condition to later develop a second or even third diagnosis. This makes it harder to classify and treat mental illnesses clearly. While life experiences and the environment matter a lot, genetics also play a major role. The goal of this study was to understand how much our genes contribute to the overlap between mental illnesses.
To do this, researchers studied the genetic data of more than 6 million people. This included over 1 million people who had been diagnosed with at least one psychiatric condition, and 5 million people with no known mental illness. By comparing the two groups, the team was able to identify specific genetic markers linked to each condition.
The results showed that the 14 mental health conditions are not completely separate. Instead, they fall into five major groups that share common genetic patterns. These groups include compulsive disorders, internalizing disorders, neurodevelopmental disorders, psychotic disorders, and substance use disorders.
For example, obsessive-compulsive disorder, anorexia, and Tourette syndrome shared many genetic features and were placed in the “compulsive” group. Another group included major depression, anxiety, and PTSD.
These three conditions shared about 90% of their genetic risks. Schizophrenia and bipolar disorder, which shared about 66% of their genetic risks, were placed in their own group. Other conditions like autism, ADHD, and substance use disorders also formed their own categories based on shared genetic features.
In total, the study found 428 genetic variants that were linked to more than one mental health condition. It also identified 101 “hot spots” on chromosomes where these shared variants were found most often.
Researchers also found that the genes involved tend to follow similar patterns in the brain. For instance, the genes tied to depression and anxiety were active in cells called oligodendrocytes, which help support the brain and nervous system.
Genes linked to schizophrenia and bipolar disorder were more active in excitatory neurons, which help send signals between brain cells.
This new information could help doctors better understand how to diagnose and treat mental health conditions. Knowing which disorders are genetically similar may lead to new treatments or improvements in how current treatments are used.
Dr. Kendler explained that psychiatry is one of the few areas in medicine without clear lab tests. Doctors rely mostly on symptoms and behaviors. Genetics is helping to fill that gap and giving scientists a better understanding of how mental health conditions are connected.
In summary, this groundbreaking study found that many psychiatric conditions are linked by shared genes. This helps explain why people often have more than one mental illness during their lives. It also provides a strong scientific foundation for improving mental health diagnosis and treatment in the future.
If you care about health, please read studies that scientists find a core feature of depression and this metal in the brain strongly linked to depression.
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