Effect of D-cycloserine on a Short Imagery Rescripting Intervention for Subclinical PTSD

The primary aim of this proof-of-concept-study is to investigate the utility of d-cycloserine (DCS; a partial N-methyl-D-aspartate receptor agonist) for enhancing the effect of a novel psychosocial intervention, imagery rescripting (ImRs). ImRs is a therapeutic technique that has shown positive outcomes for people suffering from PTSD and as an adjunct to CBT for PTSD. Patients are asked to recall their memory of a specific traumatic experience, and then to imagine an intervention that changes the course and outcome of the event to produce a more satisfying result. It is hypothesized that reconsolidation of the trauma memory is the mechanism of ImRs. DCS augments exposure therapy but also appears to enhance reconsolidation of memory. We hypothesize that DCS will enhance the effect of ImRs by incorporating safety cues into the trauma memory. Sixty adults with PTSD symptoms due to a traumatic event at least three months prior to intake will receive 4 sessions of either: CBT + ImRs, or CBT + imaginal exposure (IE). In sessions 2 and 3, participants will be randomized to receive either DCS or placebo (PLA). We hypothesize that DCS + ImRs sessions will enhance treatment outcome by facilitating reconsolidation of the trauma memories incorporating new safety cues. We also hypothesize that ImRs + PLA will provide equal or better outcomes as the IE + PLA condition. The primary outcome measure will be improvements in PTSD symptoms, as assessed at baseline, post-treatment and at 1-month follow-up. Secondary outcome measures will be self-report questionnaires assessing depression symptoms, general psychological complaints, sleep quality, quality of life, and PTSD cognitions.