Psych Setback: New Study Demolishes Genetic Link to Depression

Wednesday, November 04, 2009 by: David Gutierrez, staff writer
Tags: depression, health news, Natural News

(NaturalNews) A new analysis has strongly refuted a previous claim that a certain genetic mutation could predispose people toward clinical depression.

The meta-analysis, conducted by researchers from the U.S. National Institute of Mental Health and published in the Journal of the American Association, reviewed the results of 14 separate studies on a total of 14,250 people, 1,769 of whom had suffered from clinical depression, also known as major depression.

A widely reported 2003 study, published in the journal Science, found that people with a specific variant of a gene involved in serotonin transport were predisposed to develop major depression, but only if they had a history of stressful life events.

The neurotransmitter serotonin is believed to play an important role in depression, hence the popularity of the antidepressant drug class of selective serotonin reuptake inhibitors.

But the new study failed to find any connection with that gene. It did find that regardless of genetics, people with a history of stressful life events were 41 percent more likely to develop clinical depression.

"For an initial study that hadn't been replicated, [the Science study] was published to much acclaim," said research Kathleen Ries Merikangas said. "If it had been replicated, it was an important finding [but] geneticists have been uniformly skeptical from the beginning."

The interplay between genes and the environment is much more complex in mental illness than in other forms of sickness, said Keith A. Young of Texas A&M Health Science Center.

As many as 40 different genes may play a role in serotonin activity alone, Merikangas noted.

"Mental disorders are the most complex of all diseases," she said. "We're learning more about how genes can control the different biologic pathways in the brain, but more importantly, how that brain is wired to respond to environmental factors. We're at the very primitive stages of knowledge."

Sources for this story include: news.yahoo.com.