Psychiatric Disorders Linked Genetically

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Five psychiatric disorders, including schizophrenia, autism and depression, appear to share some genetic underpinnings, according to a new study thought to be the largest of its kind.

The work, published Wednesday in the Lancet, provides early evidence that several disorders thought to be distinct appear to have some genetic overlap, and it may help in one day diagnosing mental illness based on faulty biological processes, and not just on behavioral symptoms.

There has been previous research showing some shared genes between schizophrenia, a condition characterized by a disconnect with reality, and bipolar disorder, in which patients' moods swing between depressive lows and manic highs. But this study was the first to look at potential genetic connections between a wider range of psychiatric disorders, some of which begin during childhood and others in adulthood.

Conducted by an international collaboration of scientists, the effort compared the genes of some 33,000 people with schizophrenia, bipolar disorder, major depression, autism or attention-deficit hyperactivity disorder, and also compared them with a group of nearly 28,000 controls. Researchers looked for single nucleotide polymorphisms, or differences in a single building block of DNA, that were linked with these conditions, and identified several regions of the genome that were associated with all five diseases.

The findings suggest "there are some common liability factors, so you can have some genes that predispose you to some psychiatric disorders and other genes that direct you to specific disorders, along with environmental factors," said Alessandro Serretti, a professor at the Institute of Psychiatry at the University of Bologna, who wasn't involved in the study, but wrote a commentary to accompany it.