Post-traumatic stress disorder (PTSD) is one of the most frequent anxiety disorder in the general population (Kessler and al., 2005). Currently, the treatment of choice for PTSD is cognitive-behavioral therapy (CBT; Foa, Davidson and Frances, 1999). Based on remission rates after treatment, successful outcomes of CBT for PTSD vary between 46 and 54 % when dropouts are considered, and between 56 and 70% among those who completed their therapy (Bradley and al., 2005). Thus, there is room for improvement.
Recently, the results of two published studies on the treatment of phobia of heights (Ressler and al., 2004) and social phobia (Hofman, 2006) indicated that the efficacy of CBT was increased by adding D-cycloserine. The superior efficacy of CBT/D-cycloserine over CBT/Placebo in the treatment of anxiety disorders can result from a greater release of glutamate, a substance facilitating the extinction of fear (Davis, Myers, Ressler and Rothbaum, 2005; Richardson, Ledgerwood an Cranney, 2004). However, to our knowledge, no study has yet compared CBT/D-cycloserine to CBT/Placebo in the treatment of PTSD. The main hypothesis of the current study is that the efficacy of CBT for PTSD will be increased when combined with D-cycloserine compared to a placebo.
