Optimizing Exposure Therapy for Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a disruptive disorder, with a large psychological, social and economic impact. Exposure therapy is a first-line treatment for PTSD. Although it has proven to be an effective treatment for PTSD, fifty percent of people remain symptomatic after treatment. Extinction learning is thought to be the most important mechanism of action of exposure therapy. Extinction is based on the learning non-threat inhibitory associations. Pre-clinical studies have established strategies to enhance inhibitory learning and thereby improve treatment effects. These strategies are summarized within Inhibitory Learning Theory (ILT). This current project examines ILT-based strategies and techniques to improve exposure treatment outcome in PTSD.

The project comprises three separate randomized controlled trials (RCTs), with identical study designs and consecutive participant enrolment. Per study, patients suffering from PTSD will randomly allocated to standard exposure or ILT-enhanced exposure. ILT enhancement strategies include maximizing expectancy violation, increasing fear and stimulus variability and increasing context variability.

Optimizing inhibitory learning will enhance treatment efficacy for PTSD.

Data will be collected prior to the exposure session (T1), during the exposure session (T2), one week after the exposure session (T3) and at 3-month follow-up (T4).

Irrespective of group allocation, participants will receive one 90-minute exposure session. The control group will receive ‘standard exposure’, that is, exposure as it is currently delivered in routine clinical practice. The experimental group will receive ILT-enhanced exposure, such as 1) maximizing expectancy violation, 2) increasing fear and stimulus variability and 3) increasing context variability.