Giving a speech in public can be unnerving for just about anyone, but for people with social anxiety disorder, it's downright terrifying. Now, a small study suggests a surprising way to calm those and other social fears: a drug better known for fighting bacteria.
The drug D-cycloserine (DCS) is approved for use as an antibiotic, but it also stimulates NMDA receptors on brain cells. Animal experiments have shown that these receptors are crucial for learning, and in 2003, a team led by neuroscientist Michael Davis at Emory University in Atlanta showed that giving people with acrophobia small doses of DCS just before a therapy session helped them learn to overcome their fear of heights (ScienceNOW, 10 November 2003).
The new study tests the same idea on a far more common problem, social anxiety disorder. According to the National Institute of Mental Health, about 5.3 million people in the U.S. suffer from the disorder, which entails extreme anxiety and physical discomfort in everyday social situations. Current treatments--anti-anxiety drugs and cognitive behavioral therapy--help only about half of those afflicted, says Michael Otto, a clinical psychologist at Boston University.
To see if DCS could do better, Otto and colleagues gave the drug to people with social phobia an hour before a therapy session. During the session, the volunteers had to speak in front of a small audience and get feedback from the group. It's a stressful situation, but it helps teach patients that they often perform fine despite their anxiety, Otto says. In the study, 17 people got DCS and therapy, once a week for 5 weeks, while another 15 patients got placebo pills before therapy. Both groups improved, but the improvement was much more dramatic in the DCS group. A month after the last therapy session, the DCS patients reported less social anxiety in day-to-day life than did the placebo patients and had healthier scores on three diagnostic tests that measure anxiety, the researchers report in the March issue of the Archives of General Psychiatry.
The study's findings bode well for using DCS to augment therapy for a wide range of anxiety disorders, including post-traumatic stress disorder and obsessive compulsive disorder, says Davis. Using DCS is "fundamentally different" from the usual approach in psychiatry, he says. "You're not trying to treat the symptoms, but you're facilitating the learning that goes on with therapy."