Human genome giving insight into mental illnesses

From the intro to a Boston Globe story:

For decades, scientists seeking genes involved in mental illness reaped mainly frustration. But in recent months, painstaking analysis of the DNA of thousands of patients has yielded important, and surprising, insights into the roots of schizophrenia, bipolar disorder, and autism.

Though the findings do not translate into better ways to diagnose or treat patients,
researchers say that for the first time they are making real progress.

Dr. Thomas Insel, director of the National Institute of Mental Health, compares psychiatric genetics to a 1,000-piece jigsaw puzzle, in which researchers have just started to fit together a few edge pieces.

But "this is unprecedented progress," he said. "This is a time of real excitement in a field that up until now hasn't given us much to cheer about."

The findings, including major work published by Boston-area scientists, suggest that although mental illness is known to run in families, it may sometimes stem not from inherited defects but from spontaneous mutations that occur during earliest development in the womb.

Researchers are also finding some apparent genetic links between dramatically different disorders. For example, a genetic glitch previously shown to raise the risk of schizophrenia is also linked to autism and mental retardation, a study in the New England Journal of Medicine reported last month.

Dr. Edward Scolnick, director of the Broad Institute's Stanley Center for Psychiatric Resarch in Cambridge, has found himself telling people of late that the field of psychiatric genetics has "crossed the Mississippi."

"To explore the West, it will take a lot of work, and a lot of money," he said, arguing that the field needs an additional $200 million or more to quickly unravel the basic "genetic architecture" of severe mental illness. "There is a lot left to do. But we know how to go about it now."

The potential payoffs are great, Scolnick and other researchers say. Psychiatry is all but unique in medicine in its utter lack of chemical or biological tests to determine what a patient has.

Genetic research could lead to diagnostic assays to help determine whether, say, a troubled child suffers from bipolar disorder, impending schizophrenia, or garden-variety growing pains.

Newly discovered mutations could also lead to insights into what goes wrong in the brain, and so point the way to better drugs. They could also help clinicians better decide which treatments a given patient should try.

The recent findings represent only a beginning, and a confused one at that. Hopes were high that a few common, small mutations could explain a lot of mental illness, but it may turn out that, instead, rare mutations are often to blame. And the different types of mutations may interact, combining to produce various diseases or no disease at all.