Prescriptive variables for d-cycloserine augmentation of exposure therapy for posttraumatic stress disorder

In recent years, several studies have demonstrated efficacy of d-cycloserine (DCS) enhanced exposure therapy across anxiety disorders. In this study we examined person-level variables that predicted response to DCS enhanced exposure therapy in a chronic, mixed trauma PTSD sample. The sample consisted of 67 treatment-seeking individuals, randomly allocated to receive exposure therapy augmented with DCS (50 mg) or identical looking placebo. We examined the following baseline predictors of treatment response: (1) demographic characteristics (age, gender, marital status, and education); (2) clinical characteristics (initial PTSD symptom severity, Axis I comorbidity, depression symptom severity, and antidepressants use); (3) personality characteristics (openness, conscientiousness, extraversion, agreeableness, and neuroticism). Outcome was measured with the PTSD Symptom Scale, Self-Report, which was assessed weekly during treatment. Two prescriptive variables were identified: conscientiousness and extraversion. For high conscientious participants, those who received DCS showed better outcome than those who received placebo. And for low extraversion, DCS showed superior outcome relative to placebo. Education was identified as a prognostic variable, it predicted response across both groups: higher education was related to worse outcome. Our results provide support for the influence of personality traits on DCS augmented exposure outcome and give more insight into possible working mechanisms of this novel treatment strategy. Ultimately, this may contribute to treatment matching strategies in order to improve treatment efficacy of exposure therapy for PTSD.