June 17, 2009

Study questions genetic link in depression

A new study by U.S. researchers says it was premature to believe a single gene determines whether an individual is at increased risk for depression.

Kathleen R. Merikangas of the National Institute of Mental Health and Neil Risch of the University of California, San Francisco, led a group that re-analyzed data from 14 studies that failed to replicate one of the most celebrated findings in modern psychiatry, The New York Times reported Wednesday.

The original study, published in 2003, identified a particular variant of the serotonin gene, a brain messenger that affects mood, as determining whether a person will sink into depression after a stressful event.

Dr. Merikangas says her group found no evidence of an association between the serotonin gene and the risk of depression, no matter what a person's life experience was.

By contrast, she said a major stressful event on its own increases the risk of depression.

The new study was published Wednesday in the Journal of the American Medical Association.