The Biology Of Mental Illness

As research offers more insight, one company is ready to market a home test to measure genetic susceptibility to schizophrenia


One percent of all Americans - some 2.4 million people - have schizophrenia. An estimated 5.7 million have bipolar disorder. And 2.2 million adults have obsessive-compulsive disorder.

What if you found out tomorrow that you could become one of them?

Within two years, a Kentucky medical genetics company plans to market a home test designed to help consumers determine whether they are genetically susceptible to schizophrenia. The test, performed at home and analyzed in a lab, is the culmination of 10 years of research - and for better or worse, an example of what the brave new genomic world has wrought.

On a routine basis, researchers make headlines with a steady stream of findings that point to biological underpinnings of mental and emotional disorders that have stumped scientists for generations.

Genes, the minuscule, biological instruction manuals that tell our bodies how to develop, have been tied to cocaine addiction, bipolar disorder, schizophrenia, anorexia nervosa and more.

Still, scientists have only chipped at a mammoth iceberg. They greet some new genetic tests with grave reservations. And they worry that the emphasis on genetics gives consumers the frightening impression that they are doomed from the womb. Psychiatric illnesses are complex, they say - and there is far more to ponder than biology.

"It's a complicated public health message," says Holly Peay, co-chairwoman of the psychiatric genetic special interest group for the National Society of Genetic Counselors and associate director of the genetic counseling training program at the National Human Genome Research Institute in Bethesda.

"What we're hoping happens is that the public and individuals and families increasingly understand that mental illness has a strong biological component and a strong environmental component."

Dr. J. Raymond DePaulo Jr., chairman of the department of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, adds, "You can't separate the two. It's not nature versus nurture - it's nature and nurture."

Consider the past. Karen Mann has. She knows that once, lithium was the medication for bipolar disorder. And a dark and lingering stigma accompanied the words "mental illness." There were no options and little hope.

So four years ago, when Mann first learned she was bipolar - a disorder also called manic depression for its sweeping mood swings - she thought of someone she knew. Her grandmother had the disorder, too.

"I knew there was a genetic link," she said.

But unlike her grandmother, Mann, 30, has had the benefit of several medications. She is a psychiatric nurse and a board member for the National Alliance on Mental Illness of Maryland.

Also unlike her grandmother, she lives in an era when researchers are untangling the roots of psychiatric disorders. For example:

Australian scientists in January said that they had identified a gene that causes bipolar disorder in about 10 percent of those with the condition.

In March, the BBC reported on a U.K. Institute of Psychiatry finding that genes contribute to a person's chances of becoming a cocaine addict.

Also in March, National Institute of Mental Health researchers found that patients' response to antidepressants depended on the version of a gene they inherit.

In April, the Proceedings of the National Academy of Sciences published research that expanded previous findings on how a gene linked to schizophrenia influences the brain.

A research project in Baltimore and other locations focuses on genes that influence risk for anorexia. Elsewhere, researchers have estimated that genetics account for 56 percent of the liability for developing the disorder.

"The next big story is the brain," DePaulo says. He likens the constant patter of research to sprinkles before a good storm. These are not breakthroughs; they are the preludes to breakthroughs.

"It is an exciting time," says Stephen Doochin, executive director and chief development officer for NARSAD: The Mental Health Research Association, founded 20 years ago as the National Alliance for Research on Schizophrenia and Depression.

Over the years, the organization has broadened its reach, funding $194 million in mental health research, including $66 million in genetics-related studies.

"Pieces of a puzzle are being identified," Doochin says. "You know you've got a lot of missing pieces, but you are seeing a much broader picture."

In one respect, research already has fundamentally transformed the way mental illnesses are perceived. When Mann was first diagnosed, she remembered thinking, "There was that stigma I didn't want." But reports that biology plays a role in mental illness have helped chase away that albatross.

"It decreases the unfair stigma that society puts on the mentally ill," says Harry Brandt, director of the Center for Eating Disorders at Sheppard and Enoch Pratt Hospital and head of psychiatry at St. Joseph Medical Center.

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