This is the VOA Special English Health Report.
We all know that some people do not seem
as emotionally strong as others when life gets difficult. But why is that? A
study published in two thousand three in the journal Science offered an answer.
The study followed almost eight hundred
fifty people from birth through age twenty-six. Researchers found that those with
a short version of a certain gene were more likely to get depressed after a sad
or difficult experience.
They found that people with the normal length of the
gene were better able to weather life's storms. The gene is a transporter of
serotonin, a brain chemical involved with mood and desire for food.
The two thousand three study captured attention among
mental health professionals, and popular culture. In fact, Science magazine recognized
the discovery of "genes for mental illness" as the number two "Breakthrough
of the Year." The winner was observations about mysteries of the universe.
Last week, however, other researchers published
findings of a large new study. They report finding no link between the
serotonin transporter gene and the risk of depression. The findings appeared in
the Journal of the American Medical Association.
Risch is director of the University of California, San Francisco, Institute for
Human Genetics and a leader of the new study. He says the earlier study gained so
much recognition, it became -- in his words -- "fixed in many people's
minds as true."
The National Institute of Mental Health and Kaiser
Permanente Northern California also took part in the latest study.
researchers used information from fourteen studies involving more than fourteen
thousand patients. The scientists examined the data using the same measures as
the two thousand three study.
They found that the risk of depression was not higher
among those with the shorter gene. But they also found that stressful events
themselves did appear to increase the risk for depression.
Neuroscientist Avshalom Caspi, then at Kings College
London, led the two thousand three study. He is now at Duke University in North
Carolina. He has criticized the new study as incomplete. He says it ignores
evidence that supports the original research.
Zandi is a genetic researcher at Johns Hopkins University School of Public
Health in Maryland. He agrees that this latest study is not the final word.
PETER ZANDI: "After many years of trying to figure
out what is going on with the genetic cause of depression, we're still not
that's the VOA Special English Health Report, written by Caty Weaver. For more
health news, go to voaspecialenglish.com. I'm Steve Ember.