For years psychiatrists have been searching for clues that would explain why some people fall into depression while others, perhaps facing greater adversity, do not. New research indicates the reason my lie in our human wiring.
A study using brain scans has raised the possibility that a gene may make people more susceptible to anxiety and depression by reducing their ability to fully process negative emotion.
According to the study, people with the suspect gene showed less gray matter and weaker connections in the mood-regulating circuit. The integrity of the circuit accounted for about 30 percent of test subjects' anxiety.
The study, by researchers at the National Institute of Health's (NIH) National Institute of Mental Health (NIMH) and published in the May 8, 2005 online edition of Nature Neuroscience, discovered mood-regulating circuit by analyzing how test subjects processed information.
Comparing the brain to an orchestra, researchers attempted to determine whether its various parts were all playing the same tune, and if not, whether the gene was responsible.
In the new study, the researchers found that one of the two types of the gene, the "short" type, contributes to general anxiety and risk of depression related to stress. It also heightens the brain's response to viewing scary faces.
Researchers examined the brain scans of 114 healthy people to see the effect of having one or two copies of the short type of the gene. Humans are equipped with two copies of the gene, inherited from their parents. Each copy is either "long" or "short."
The study's authors say the discovers probably won't lead to any breakthrough treatments for mental illness, at least not right away. They note the in some current therapies, the brain's circuitry is already the focus of attention.
