D-cycloserine (DCS), used in concert with psychotherapy, is an effective treatment for some anxiety-related disorders

A tuberculosis drug called D-cycloserine (DCS), used in concert with psychotherapy, is an effective treatment for some anxiety-related disorders, according to research by scientists at Emory University School of Medicine and the Center for Behavioral Neuroscience (CBN).

The study was led by Michael Davis, PhD, Kerry Ressler, MD, PhD, and Barbara Rothbaum, PhD, of the Department of Psychiatry and Behavioral Sciences and is reported in the November issue of the Archives of General Psychiatry.

In the study of 28 people suffering from acrophobia, which is an abnormal fear of heights, either DCS or placebo was given to study participants, followed by two virtual reality sessions that simulated standing in a rising glass elevator. Compared to subjects who took only placebo, those treated with DCS experienced a significant reduction in their fear of heights that was maintained for at least three months (the longest time tested) after concluding therapy.

The mechanisms governing the fear response, located in a region of the brain called the amygdala, function abnormally in an acrophobic's brain. DCS binds to neurotransmitter receptors in the amygdala called NMDA (N-methyl-D-aspartate) receptors. When combined with virtual reality exposure therapy, DCS facilitates fear extinction in the acrophobic's brain.

"Cognitive behavioral psychotherapy uses a process called 'fear extinction' to treat individuals with phobias, as well as more complicated problems, such as post-traumatic stress syndrome," said Dr. Davis.

"Fear extinction involves repeated exposure to a fearful memory or object, in the absence of adverse consequences. Because it was known that DCS improves NMDA synaptic transmission and we found it improved extinction in rats, we hoped to facilitate the effects of cognitive behavioral therapy by combining DCS with virtual reality therapy in humans. Our results demonstrate that this combination is effective, and that these effects can be long lasting."