In the latest in a series of studies of how mice acquire, express and extinguish conditioned fear, the UCLA team finds yohimbine helps mice learn to overcome the fear faster by enhancing the effects of the natural release of adrenaline. Adrenaline prompts physiological changes such as increased heart and metabolism rates in response to physical and mental stress.
Writing in the March/April edition of the peer-reviewed journal Learning and Memory, the team reported that mice treated with yohimbine overcame their fear four times as fast as those treated with vehicle or propanolol, a medication commonly used to treat symptoms of anxiety disorders by blunting the physiological effects of adrenaline.
Yohimbine is most commonly used to treat erectile dysfunction. It can cause anxiety in susceptible persons, and should never be used without a doctor's recommendation and supervision.
These new findings come on the heels of evidence published by the same UCLA research team last fall (Journal of Experimental Psychology, October 2003) that suggests full, frequent exposure to a fear during behavioral therapy may be more effective in treating anxiety than the standard practice of gradual, spaced exposure. For example, it may be more effective to treat fear of heights by taking a patient straight to the top of a tall building in rapid succession, rather then taking them to increasingly higher floors over a lengthy period of time.
"We are at the threshold of a new era in our understanding and treatment of anxiety disorders," said Dr. Mark Barad, the UCLA Neuropsychiatric Institute's Tennenbaum Family Center faculty scholar and an assistant professor of psychiatry and biobehavioral sciences. "Current treatment protocols use medications intende
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University of California - Los Angeles