Tuesday, April 18, 2006

Is Anxiety the Cause or Effect?

Experts have been asking for sometime now if the anxiety that is often associated with chronic depression a cause or effect of the illness?

New research performed on mice suggests that chronic stress may be a trigger and not a symptom of depression. These findings are in the April issue of the Journal Behavioral Neuroscience. The research team from Harvard Medical School and McLean Hospital in Boston believes that the findings could also help improve treatments for the disorder.

It is already a known fact that those with depression tend to have higher levels of the human stress hormone called cortical, but it has never been clear if this was a cause or effect of depression. According to the new mouse study, long term exposure to cortical may actually contribute to depression.

Researchers exposed mice to twenty four hours and seventeen to eighteen doses of the rodent stress hormone corticosterone. This hormone was put in their water so that the stress of having an injection would not interfere with the results. This same method was done to a group of mice with a shorter term of exposure.

Those who had long term exposure took longer time emerging from a small dark compartment into a brightly lit open area, which is a common behavioral test of anxiety in animals. These results suggest that these mice were more fearful and less willing to explore their new environment.

Researchers also found that mice with longer exposure showed dulled reactions to being startled, which is an indication that their nervous system was overwhelmed.

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