MessageToEagle.com - Scientists work hard to unravel what causes psychiatric disorders and how to better diagnose and treat them.

Genetic contributions to psychiatric disorders do not in all cases map to present diagnostic categories, a new family and twin studies suggest.

Recently, scientists conducted the largest genetic study of mental illness concentrating their studies on five mental illnesses that share genetic links.

The illnesses - that are related in some way are - major depressive disorder, schizophrenia, autism spectrum disorder, attention deficit-hyperactivity disorder (known as ADHD) and bipolar disorder.

"These disorders that we thought of as quite different may not have such sharp boundaries," says Jordan Smoller of Massachusetts General Hospital, one of the lead researchers for the international study appearing in The Lancet.

That has implications for learning how to diagnose mental illnesses with the same precision that physical illnesses are diagnosed, says Bruce Cuthbert of the National Institute on Mental Health, which funded the research.

"We are still in the early stages of understanding what are the causes of mental illnesses, so these are clues," Smoller says.

The Psychiatric Genomics Consortium, a collaboration of researchers in 19 countries, analyzed the genomes of more than 61,000 people, some with one of the five disorders and some without. They found four regions of the genetic code where variation was linked to all five disorders.

Of particular interest are disruptions in two specific genes that regulate the flow of calcium in brain cells, key to how neurons signal each other. That suggests that this change in a basic brain function could be one early pathway that leaves someone vulnerable to developing these disorders, depending on what else goes wrong.

For patients and their families, the research offers no immediate benefit. These disorders are thought to be caused by a complex mix of numerous genes and other risk factors that range from exposures in the womb to the experiences of daily life.

"There may be many paths to each of these illnesses," Smoller cautions.

At the same time, the study offers a lead in the hunt for psychiatric treatments, says NIMH's Cuthbert. Drugs that affect calcium channels in other parts of the body are used for such conditions as high blood pressure, and scientists could explore whether they'd be useful for psychiatric disorders as well.

The findings make sense, as there is some overlap in the symptoms of the different disorders, he says.

People with schizophrenia can have some of the same social withdrawal that's so characteristic of autism, for example. Nor is it uncommon for people to be affected by more than one psychiatric disorder.

Funding:
National Institute of Mental Health.

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