Preliminary data from a study using the drug d-cycloserine (DCS) combined with virtual reality exposure therapy suggests that the combination therapy is effective in reducing elevated startle response and decreasing symptom severity in military personnel with post-traumatic stress disorder (PTSD).
The data was presented at the American Psychiatric Association meeting in Washington, DC.
Barbara Rothbaum, PhD, and Kerry Ressler, MD, PhD, faculty members of the Department of Psychiatry and Behavioral Sciences at Emory University are leading a study that began in 2006 using DCS combined with virtual reality therapy to treat PTSD. The National Institute of Mental Health of the National Institutes of Health funds the study.
"This particular combination of treatment techniques and medication arises from years of studying fear and, most importantly, what decreases fear," says Rothbaum. "We are very excited about the prospects of this combined therapy."
Rothbaum and Ressler and Michael Davis, PhD, also an Emory faculty member, completed the first human trial using DCS with virtual reality exposure therapy for acrophobia, or fear of heights, in 2004.
The process of extinction - a process by which a patient is presented with a fearful situation repeatedly with no adverse consequences - uses a brain protein called the NMDA receptor.
Previous lab experiments by Davis and his team of researchers showed D-cycloserine speeded up the extinction of fear. This was predicted based on work by other scientists who had shown that DCS, originally used at high doses to treat tuberculosis, made the NMDA receptors work better when it was given at low doses.
Study participants are military personnel returning from Iraq who have been diagnosed with PTSD. All participants meet individually with a therapist for six sessions and receive virtual reality treatment for five of those sessions. Participants are randomized into three separate groups to determine which medication they receive immediately prior to each virtual reality session: those who receive a placebo, those who receive DCS and those who receive alprazalam (Xanax). Participants take one pill before each virtual reality therapy session for a total of only five pills.
Each group meets with a trained therapist once a week for six weeks. The therapist helps veterans confront and cope with memories of what happened to them in Iraq using virtual reality. The virtual reality exposure therapy portrays scenes, sounds, vibrations and odors related to combat in Iraq. Researchers also test galvanic skin response and heart rate, and will measure the level of cortisol, a stress hormone that is in the saliva.
A total of 150 volunteers will be enrolled. Participation in the study is confidential.
Rothbaum is a professor of psychiatry and behavioral sciences and director of the Trauma and Anxiety Recovery Program in Emory University School of Medicine. In addition to being Emory faculty, Ressler and Davis are researchers at the Yerkes National Primate Research Center and members of the Center for Behavioral Neuroscience. Ressler is a Howard Hughes Medical Institute investigator.
Maryrose Gerardi, PhD, assistant professor of psychiatry and behavioral sciences is the primary therapist for the study. The Virtual Iraq module was developed by Dr. Skip Rizzo and colleagues at the Institute for Creative Technologies and School of Gerontology at the University of Southern California.
Ressler and Davis are co-authors of a patent for the use of D-cycloserine for the specific enhancement of learning during psychotherapy and are co-founders of Therapade Pharmaceuticals, LLC, which holds the patent rights for this indication. Dr. Rothbaum is a co-owner of Virtually Better, Inc. (VBI) that creates virtual reality environments for therapeutic use, although VBI did not create the Virtual Iraq module being used in this study. The terms of these arrangements have been reviewed and approved by Emory University in accordance with its conflict of interest policies.
A podcast describing Post-traumatic Stress Disorder and the DCS/Virtual Reality study can be heard at: