A gene variation long thought to increase a person’s risk for major depression when paired with stressful life events may actually have no effect, according to a new analysis. The result challenges a common approach to studying depression risk factors.
Most mental disorders are thought to be caused by a combination of many genetic risk factors interacting with environmental triggers. Finding the exact combinations of factors, however, has been a significant challenge. Advances during the past decade have led to powerful tools for studying how genes and the environment interact to affect the risk for disease. In 2003, these advances allowed scientists to show that variation in a gene called the serotonin transporter gene affected the risk of major depression in people who had a number of stressful life events over a 5-year period.
Serotonin is a chemical messenger that helps brain cells communicate. The serotonin transporter directs serotonin from the space between brain cells back into the cell for reuse. Since the most widely prescribed class of medication for treating major depression acts by blocking this protein, it’s been a prime suspect in mood and anxiety disorders.
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