Research confirms antibiotic increases effectiveness of psychotherapy for anxiety

However, tolerance may become a limiting factor

Anxiety is a normal human response to stress, but in some, it can develop into a disabling disorder of excessive and irrational fears, such as obsessive-compulsive disorder, panic disorder, or posttraumatic stress disorder.

Effective treatments are available and can involve either behavioral therapy or medications. Although "it makes intuitive sense that combining these two treatments would result in even better results," David Tolin, Ph.D. notes that has unfortunately not yet been the case and the majority of the evidence suggests that combined therapy is no more effective than behavior therapy alone, and in some cases can even be less effective.

Dr Tolin is one of the three authors of a meta-analysis published in the journal Biological Psychiatry, in which they evaluated a potentially important new treatment paradigm for anxiety.

Dr Tolin explains the impetus behind their analysis: "Recently, several researchers have tried a radically different approach: instead of just throwing two effective monotherapies at the problem, they have instead looked at medications that specifically target the biological mechanisms that make psychotherapy work in the first place." John H. Krystal, MD, Editor of Biological Psychiatry and another of the study's authors, adds that "there has now been a sufficient amount of research in this area to take a step back to look at the basic research conducted in animals and the initial clinical trials."

Their analysis examined the effectiveness of adding D-cycloserine, an old antibiotic drug long approved for the treatment of tuberculosis, to exposure-based fear treatment in animals and humans. The meta-analysis, a pooling of the published literature on this approach, provides evidence that D-cycloserine enhances the learning process in the brain, indicating that, unlike antidepressants and benzodiazepines, it may improve the effectiveness of behavioral therapy in achieving fear extinction.

There is a caveat, however, as the authors also discovered that tolerance may develop to this effect. Dr Krystal comments that, if so, "it may be best used before therapy sessions to 'warm up the brain' and make it more responsive to the treatment sessions rather than as a daily treatment."

Dr Tolin makes an additional, important observation, "Another very exciting aspect of this work is that it's one of the few really good examples of translational research in psychiatry: taking basic science from the laboratory, in this case animal studies, and translating that research into useful interventions for humans."

Although additional research is clearly necessitated, this confirmation of the effectiveness of D-cycloserine is a positive step forward in improving treatments for individuals suffering with anxiety disorders.

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Norberg MM, Krystal JH, Tolin DF. A Meta-Analysis of D-Cycloserine and the Facilitation of Fear Extinction and Exposure Therapy. Biol Psychiatry. 2008 Jun 15;63(12):1118-1126.   [Abstract]