The drug, D-cycloserine (DCS), has been used to treat tuberculosis and has also been shown to stimulate learning, according to The Center for Anxiety and Related Disorders.

In a double-blind, placebo-controlled study, 27 patients were randomized to receive 50 mg. of D-cycloserine or placebo one hour before each of four exposure therapy sessions, conducted as part of an overall five-session treatment plan.

During the sessions, participants were required to give speeches in front of other group members or a video camera and then listen to feedback from their peers.  

Patients who received exposure therapy plus the active drug reported significantly less anxiety compared with the placebo group.

The results of the study are published in the March issue of the Archives of General Psychiatry.

An earlier study conducted at Emory University demonstrated similar results in individuals with acrophobia, the fear of heights.