May 15, 2012 -- Scientists have developed a test that may be able to predict who is at risk for schizophrenia, a complex mental illness that is thought to run in families. To develop the test, scientists used a new approach to identify a comprehensive group of genes most likely linked with the disease.
"We have really broken the code," says researcher Alexander B. Niculescu III, MD, PHD, associate professor of psychiatry and medical neuroscience at the Indiana University School of Medicine, Indianapolis. "We have identified the most comprehensive and best list of genes so far."
The new model depicts schizophrenia as a disease that occurs from a mix of genetic variations affecting the brain's development and connections, along with stress and other environmental factors.
The study is published in Molecular Psychiatry.
Schizophrenia affects about 1% of Americans, according to the National Institute of Mental Health. The chronic, disabling disorder is marked by symptoms such as hallucinations, paranoid thoughts, and disorganized thinking. Although treatable, many patients refuse medications because of the side effects.
For years, scientists have known that genes and environment both play a role in schizophrenia.
"It was suspected that there were likely many genes involved, but the evidence from genetic studies was variable and inconclusive for many of them," Niculescu tells WebMD.
Genetics of Schizophrenia
The researchers drew information from genome-wide association studies, independent studies, and other sources to develop the list of genes.
When they had the list, they tested it in four different groups of people. They found it could identify those with schizophrenia and those without. The test was accurate in 2 out of 3 people, Niculescu says.
The genetic risk test is at very early stages. If all goes well, a commercial company could develop it within in three to five years, Niculescu estimates.
The test would be useful for children in high-risk families in which a relative has the disorder, he says.
"In this way, if the score is higher, those children could be followed more closely," he says. Treatment could be started earlier for better results, he says.
It is a prediction only. "In the end, your genes are not your destiny."
"A higher score on the test we developed just means your brain connectivity may be be different," he says.
That could lead to creativity or illness, depending on other genes and environmental factors.
The researchers also found much genetic "overlap" between schizophrenia and other disorders, including bipolar and anxiety disorders.
That may help put the focus on treating symptoms, Niculescu says. That, in turn, may reduce the ''labeling" of mental illness and its stigma, he says.
Niculescu is a founder of Mindscape Diagnostics. A co-author is a founder of Cypher Genomics.
Genetics of Schizophrenia: Perspective
The researchers have simplified what is a ''very confusing area," says Stephen R. Marder, MD, professor of psychiatry at the Semel Institute of the University of California Los Angeles David Geffen School of Medicine. He reviewed the findings for WebMD.
"They have integrated information from very large genetic studies on schizophrenia and other kinds of studies and come up with patterns that may help us understand the genetics of schizophrenia," he says.
The new model, he says, suggests that risk is affected by how the brain develops and forms connections, and how factors in the environment may affect genes.
"This new research points to looking not so much at specific abnormal genes, but looking at actually what the genes do in the brain to make people vulnerable to schizophrenia," he says.
Marder reports consultant work for Amgen, Abbott, Pfizer, Lundbeck, Roche, and Otsuka Pharmaceutical Company. He is also director of the Mental Illness Research, Education, and Clinical Center at the VA of Greater Los Angeles.