Researchers Find New Psychiatric Applications for Scopolamine
Old anticholinergic drug might treat depression and anxiety (Feb. 12)
Scopolamine is an anticholinergic agent with many uses. For example, it prevents nausea, vomiting, and motion sickness.
Now, the drug is re-emerging as an antidepressant, with recent studies showing that it can rapidly improve mood in depressed patients. In addition, in a new study published in Biological Psychiatry, researchers at the University of California–Los Angeles have found that scopolamine may also be a possible treatment for anxiety disorders.
Exposure therapy — where the key goal is the elimination of fear through repeated “safe” exposure to the threat — is commonly employed for the treatment of anxiety disorders. However, its effectiveness is diminished because humans and animals alike tend to be sensitive to context, causing “extinction learning” to be dependent on the environment in which it occurs, the new report says. This makes memories formed during extinction unstable. As a result, extinguished fears commonly return when people put themselves in new situations.
In an effort to solve this dilemma, researchers took a novel theoretical approach. Employing an animal model of exposure therapy, they found they were able to disrupt contextual processing during extinction in rats using low doses of scopolamine, which blocked the return of fear when the rats were exposed to both the original and a new context.
Scopolamine also slowed the rate of extinction memory formation, which was overcome by adding training sessions.
Taken together, these findings indicate that scopolamine may serve as a promising pharmacological adjunct to exposure therapy by improving a patient’s resiliency to environmental changes, according to the authors.
Source: Elsevier; February 12, 2013.