Background: Syrians represent the largest group among refugees in Germany. Many of them were exposed to sequential traumatizing events including war, escape and post-migration stressors, which significantly increase the risk to develop symptoms of posttraumatic stress and other mental disorders. However, there is a lack of adequate treatment options for traumatized refugees in Germany. Moreover, their access to psychosocial care is often restricted due to legal regulation, language barriers, and unclear cost coverage. We therefore aim to develop a low-threshold supportive self-help app for Syrian refugees with posttraumatic stress symptoms. By conducting a randomized controlled trial, we further aim to evaluate the apps' efficacy, usability, acceptance, and economic health benefit/cost-effectiveness. Methods: We will develop a modular, interactive self-help app in Arabic, which will be grounded on cognitive-behavioral models for the treatment of posttraumatic stress. Subsequently, screened positive (i.e., Syrian refugees, 18-65 years old, mild to moderate posttraumatic stress symptomatology as quantified by the Posttraumatic Stress Diagnostic Scale for DSM-5/PDS-5) participants (ideally up to n = 234) will be randomly allocated to an intervention (IG) and control group (CG), respectively. Participants in the IG will gain access to the self-help app for one month, while participants in the CG will receive psychoeducational reading material in form of a comprehensive brochure on traumatization and posttraumatic stress. Measurements are scheduled before the intervention (T0), directly after the intervention (T1, one month later) and three months after the intervention (T2). Using linear mixed effect models, we will investigate change in posttraumatic symptomatology. We will also test for changes in secondary outcomes such as depression, anxiety, and quality of life. Moreover, we will inspect the usability and user acceptance of the app. To evaluate the app in terms of its economic health benefit, the incremental cost-effectiveness ratio will be calculated. Discussion: We plan to make the app freely available to the general public after evaluation. Thus, the app can help to add-on to routine care, which currently lacks sufficient and appropriate treatment options for Syrian refugees. Trial registration: German Clinical Trials Register/Deutsches Register Klinischer Studien (DRKS). Registration ID: DRKS00013782. Registered: 06th of July 2018. © 2019 The Author(s).

posttraumatic stress Digital health RCT intervention traumatization Refugee Self-management program Syria App Mhealth trauma

clinical protocol clinical outcome depression Germany refugee anxiety disorder psychoeducation human controlled study randomized controlled trial Aged quality of life health program Arabic (language) male female Posttraumatic Stress Diagnostic Scale PDS 5 software scoring system Article major clinical study Syrian adult posttraumatic stress disorder DSM-5 Self Care clinical effectiveness cost effectiveness analysis self help