The modern psychotherapy has a great arsenal of drugs that may relieve the patient’s pain, help them overcome their disturbances and personality disorders. However, the majority of drugs is capable of only dealing with the consequences of disorders’ effect on patients and can ease clinical manifestations thereof. An innovative stage in psychiatric treatment has been entered with the start of D-cycloserine (DCS) application. D-cycloserine is a putative nootropic agent known to have profound effect on the N-methyl-D-aspartate (NMDA)-glutamate synapses that are responsible for the functions of learning and memory (Allen, 1996). This unique partial agonist has proven to have profound positive effect in treating tuberculosis, but recent research on animals enabled scientists to assume that DCS will be highly helpful in the facilitation of fear extinction in combination with exposure therapy in treating human patients with anxiety disorders (Hofman et al., 2006).

There are several reasons for the DCS propriety in treating various psychotic disorders from the point of view of NMDA receptors; as noted by Ressler et al. (2004), “some disorders, particularly the anxiety-related disorders exemplified by specific phobia, have an emotional learning component to them that can be facilitated with psychotherapy” instead of dealing with the abnormalities in their ultimate sense. Looking at the mechanism of memory formation and the significance of an emotional element in it, one will clearly realize why NMDA-glutamate synopses’ stimulation has so much potential for the psychiatric treatment progress.

Much experimental work has been conducted regarding the effect of DCS on phobia treatment, e.g. acrophobia as examined in the works of Ressler et al. (2004) and Davis et al. (2006). Both studies are dedicated to the DCS role in treating acrophobia and assessment of the overall DCS impact on the progress of corrective psychopathology. Ressler et al. (2004) used DCS as an adjunct in the extinction learning processes of humans in the period of virtual reality exposure (VRE) therapy proven successful for treatment of phobias and disorders. The task was to find out whether acute treatment with DCS would augment extinction of fear for patients having acrophobia. The results showed significant differences in fear reduction in groups with placebo and drug groups, which proves the indiscriminate role of DCS in fear extinction. Some other findings include: the conclusion that DCS does not reduce the level of fear or avoidance of fear during the therapy, DCS enhances extinction of fear within the virtual environment, and that the DCS extinction effect may last for about 3 months (Ressler et al., 2004). Generally, Ressler et al. (2004) make conclusions on the reduction of general acrophobia measures with the help of DCS and the scope of overall subjective and functional improvement.

Davis et al. (2006) support these findings; the researchers also base their research theoretically, exploring the role of DCS in fear conditioning. Authors also examine the potential for causing generalized extinction and prove its possibility, which means that “DCS facilitates extinction by enhancing the devaluation of the US representation elicited by the presentation of light CS” (Davis et al., 2006). The US stands here for the unconditioned stimulus, and CS is a conditioned stimulus. Generalized extinction may lead to loss of fear to any cue, which is potentially dangerous. Nonetheless, DCS has proven to reduce reinstatement of fear after extinction and successfully combines with behavioral exposure therapy (Davis et al, 2004). It is surely not the only study that supports the combined usage of behavioral therapy and DCS, which will be clear further.

Possible assistance of DCS in fear conditioning in combined usage with CBT is proven in the discussion of obsessive-compulsive disorder treatment in the article of Rothbaum (2008). The arguments that the author uses are the serious role of DCS in fear conditioning with further help in learning new behaviors that can be provided by CBT (Rothbaum, 2008).

Rothbaum (2008) utilizes data from previous successful cases of treating three anxiety disorders by CBT and medications. If one discusses medicines alone compared to CBT in treating diverse anxiety disorders, OCD included, no prevalence was found. Besides, prevalence of CBT combined with medications does not also reveal itself experimentally; but this is true only about traditional medicines like alphrazolan, buspirone, imipramine etc. However, as soon as experiments were pursued under the same conditions but with the application of DCS, much more positive results were shown. The author assumes their dependence on the mechanism of DCS effect and makes positive evaluations of the discovered perspective (Rothbaum, 2008).