Abstract
Interventions administered shortly after a traumatic event have the potential to prevent posttraumatic stress disorder (PTSD) and related mental health conditions. A key challenge in delivering such interventions is understanding how PTSD symptoms develop in the acute post-trauma period, defined as the first 30 days after a trauma. Mobile devices have the potential to transform the way symptoms are assessed and how treatment is delivered in that they can capture the dynamic and nuanced nature of symptom progression after trauma. Symptoms can be assessed through active strategies that require user input, such as self-report, or through passive strategies, such as location information. Adaptive mobile interventions can be tailored to target PTSD symptoms as they appear and ultimately prevent more chronic courses of illness. Considerations for how such mobile strategies should be implemented are discussed.