Internet-based intervention for Posttraumatic Stress Disorder (PTSD) in soldiers: Exploring mechanisms of treatment outcome.

Type of intervention: Therapist-guided internet-based intervention. The intervention is delivered via an online platform. Duration and general information: Intervention and treatment procedure: The internet-based intervention lasts 5 weeks and includes 10 structured writing assignments. Patients complete two assignments per week. Each assignment requires approximately 45 minutes of writing time. Communication between patient and therapist takes place within a secure messaging system that is part of the online intervention platform. Participants receive standardized instructions for each of the writing tasks and written feedback after one working day from a trained psychotherapist (personally assigned) after eight of the ten writing tasks. Participants do not receive feedback after session 2 (biographical reconstruction) and after session 5 (moderate exposure). The feedback consists of generic parts that are complemented by individual feedback tailored to the participants’ specific needs (e.g. recognition for disclosing experiences, encouragement for exposure to traumatic event, reinforcement and motivation). Additionally, participants are able to contact the intervention team if technical support is required. For questions related to the treatment, patients can contact their personal therapist via e-mail (additional contact on demand). Requests will be answered within one working day. Adherence: Login of participants is monitored and participants are asked to determine a specific date at which they plan to work through the next assignment. If participants miss an intended date, the therapist receives an automatic notification and contacts the client via e-mail. Assessment and evaluation: Before and after the treatment, patients are invited for 3 (treatment group, n=50) or 4 (wait list control group, n=50) face-to-face diagnostic and assessment sessions at the German Army Hospital in Berlin. Trained research staff conducts structured clinical interviews (CAPS, M.I.N.I. and Mini-ICF-APP) with all patients before onset of the treatment. Furthermore, the diagnostic assessments include self-report questionnaires (e.g. PCL-5), psychophysiological measures (e.g. eye-tracking, heart rate) and an assessment of biomarkers (e.g. HPA-axis markers, cytokines and oxytocin). In addition, patients are asked to collect saliva samples for two consecutive weekdays after each assessment session. Saliva samples for cortisol analysis as well as heart rate measurements are also included in two of four exposure sessions (see below) and are guided by instructions via the online-platform. Training of research staff and psychotherapists: The research staff consists of four psychologists that receive practical training for conducting clinical interviews and all assessment procedures prior to the study onset. Specifically, training takes 3 days (8 hours each) and includes performance of clinical interviews (M.I.N.I., CAPS) and concrete instructions on how to apply assessments (heart rate, sleep EEG, eyetracking assessment). Two experienced psychotherapists receive a 2-day-training (8 hours each) on how to use the online intervention platform and on how to implement the intervention protocol and to interact with participants. The study team is accompanied by a military study physician who provides additional training for critical situations and population specific demands. Supervision is scheduled weekly. Contents, aims and methods of the intervention in detail: Biographical reconstruction (Session 1-3) Topic: Essays on three life phases: 1) from birth to age of 10, 2) age of 11 to 18, 3) age of 18 until occurrence of the traumatic event(s) Aim: Narrative reconstruction of own biography; identification of resources Method: Written biographical reconstruction Moderate Exposure (Session 4-7) Topic: Repeated detailed description of the traumatic event(s) Aim: Alteration of trauma memory Method: Written trauma exposure Cognitive Reappraisal (Session 8-10) Topic: Supportive letter to younger self, coping with events in the future Aim: Integration of traumatic event in biography, to gain a new perspective on the event (e.g., challenging dysfunctional automatic thinking, correction of unrealistic assumptions) Method: Written cognitive restructuring