Effects of Mindfulness-Based Internet Intervention on ICD-11 Posttraumatic Stress Disorder and Complex Posttraumatic Stress Disorder Symptoms: a Pilot Randomized Controlled Trial.

Objectives: A substantial proportion of trauma survivors with posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD) continue to experience symptoms even after trauma-focused therapies. Internet-based interventions could facilitate access to treatment for PTSD and CPTSD. The current pilot study aimed to investigate the effects of mindfulness-based internet intervention on PTSD and CPTSD symptoms. Methods: A randomized controlled trial (RCT) design with two measurement points (pre-test and post-test) was used to investigate the effects of a structured mindfulness-based internet intervention on PTSD and CPTSD symptoms as well as anxiety, depression, and positive mental health. In total, 70 university students with high levels of PTSD and CPTSD symptoms based on ICD-11 criteria participated in the study: 31 in the intervention group and 39 in the waiting list control group. Results: We found that the mindfulness-based internet intervention reduced CPTSD disturbances in self-organization (DSO) symptoms (ES = - 0.48 [- 0.96; 0.00]), particularly negative self-concept (ES = - 0.72 [- 1.21; - 0.24]) and disturbances in relationships (ES = - 0.55 [- 1.03; - 0.07]). Moreover, the intervention reduced the symptoms of PTSD sense of threat (ES = - 0.48 [- 0.96; - 0.01]) and promoted positive mental health (ES = 0.51 [0.03; 0.99]). High user satisfaction and good usability of the intervention were reported. Conclusions: Promising treatment effects were found, indicating that mindfulness-based internet intervention can reduce CPTSD symptoms and have a positive effect on mental health among youth in general. The findings of the current study contribute to the further development of trauma care using internet-delivered interventions.Trial registration: ClinicalTrials.gov NTC04333667 (3 April 2020).