The five most common mental illnesses all have a common genetic root, according to a new study published Wednesday in the journal Lancet.
In the largest study ever to examine genetics and mental health, researchers found that autism, attention deficit disorder, bipolar disease, schizophrenia and major depression all share the same genetic root – a finding that may pave the way to the discovery of the underlying causes of mental illness.
“We have been able to discover specific genetic variants that seem to overlap among disorders that we think of as very clinically different,” said the study’s lead author, Dr. Jordan Smoller of Massachusetts General Hospital in Boston, in an interview with NBC News.
Although the study didn’t cover every psychiatric illness, it did show that the five most common mental diseases have a genetic link.
The study involved over 33,000 psychiatric patients, which researchers compared to nearly 28,000 mentally healthy individuals without any psychiatric disease, performing a scan of all the DNA in both groups.
As stated in their report, the researchers “aimed to identify specific variants underlying genetic effects shared between the five disorders” of autism spectrum disorder, attention deficit-hyperactivity disorder, bipolar disorder, major depressive disorder, and schizophrenia.
The results showed a common genetic root linking all five mental diseases to specific chromosomes and genetic areas known to be involved in controlling cell function called calcium channels.
This finding could suggest that a genetic weakness upstream in the development of the brain could lead to a variety of psychiatric symptoms, perhaps influenced by other genes, or by the environment as well.
“We didn’t know going in that we would be able to find commonality with such a broad array of disorders,” Smoller said. “The fact that a particular pathway emerged as being relevant was also surprising. We didn’t know about that one before.”
Dr. Ken Duckworth, medical director of the National Alliance on Mental Illness, hopes the findings may help dispel some of the stigma that still surrounds psychiatric diseases.
“Ultimately this kind of research will give us a return in terms of social attitudes toward brain-based illness,” Dickworth said. “If you can understand an illness process, it doesn’t seem so mysterious and terrifying.”