Unlearning Fear: Lessons From Mice
Anxiety Disorders Lessen During Exposure Therapy
Fear extinction seems to be a two-step process, Barad explains. A certain amount of intense exposure to the feared situation will trigger the unlearning process.
Once that process is underway, it is time for periods of "training" -- again facing the fear in blocks of time. But that training should be delayed a bit, as should successive training periods, to let new learning become integrated in the memory, says Barad. Then anxiety disorder should be overcome.
Michael Davis, PhD, professor of psychiatry and behavioral sciences at Emory University School of Medicine in Atlanta, has conducted similar studies involving rats.
The complexity lies in the "tension" between the fearful memory and the new response, he explains. "It's easy to quickly become fearful of something one perceives as dangerous. But extinction is new learning, and it will always compete with the old memory. The question is: Is the extinction response strong enough to extinguish that lingering memory?"
Exposure therapy indeed works, as his clinical experience and laboratory experiments have shown. However, he's found that either multiple exposures in a very short period of time -- or exposures spaced quite far apart -- will get someone past anxiety disorder, Davis tells WebMD. Anything in between just doesn't work, he says.
Barad's study sheds light on the nuances of fear extinction and anxiety disorders, but it's not likely the final word, Davis says.