The potential effect of d-cycloserine on the development of anxiety during exposure sessions in patients with agoraphobia

Abstract

IntroductionCombination of exposure therapy with d-cycloserine (DCS) in patients suffering from anxiety disorders yielded promising results regarding treatment outcomes. However, less is known about short-term effects of DCS during the treatment process, e. g. its potential influence on anxiety during exposure sessions. In this exploratory secondary analysis using data from a randomized, double-blind, placebo-controlled trial, we investigated longitudinal changes in anxiety during exposure in agoraphobic patients receiving DCS or placebo (PBO). Methods73 patients suffering from agoraphobia (with or without panic disorder) were treated with 12 sessions of individual cognitive behavioral therapy including three exposure sessions. Patients were given either PBO or 50mg of DCS after each successful exposure. Multilevel modeling was used to analyze changes in outcomes measured in subjective units of distress (SUDS) over three time points (i.e. the exposure sessions) in the two groups. ResultsWe observed a decline in several SUDS outcomes in the DCS group, namely initial anxiety, maximum anxiety during exposure and within-session habituation, while the PBO group mostly maintained similar levels of anxiety from session to session. Anxiety at the end of exposure appeared to be stable in the DCS group as well. DiscussionOur findings suggest potential short-term effects of DCS on anxiety during exposure. Long lasting and high degree of anxiety over exposure sessions is burdensome for the patients. Thus, modifications to reduce anxiety during exposure or to accelerate the learning process while maintaining the same treatment efficacy could be desirable. However, given the exploratory nature of the analyses, confirmatory studies testing the hypothesis of a decline of SUDS in agoraphobic patients are needed before confident conclusions can be made.