Efficacy of Internet-delivered Cognitive-behavior Therapy for PTSD

PTSD is a debilitating psychiatric disorder strongly linked to subsequent psychiatric and medical problems. Trauma-focused cognitive behavioral therapy (CBT-T) such as prolonged exposure is an effective treatment for PTSD and is recommended in most clinical guidelines as first-line treatment but is seldom available in regular care. A possible solution to significantly improve access to evidence-based treatment would be the use of remotely delivered digital intervention. Preliminary research shows that therapist-guided internet delivered to be effective and safe, but studies have typically excluded patients with severe PTSD. Before this type of treatment can be offered in regular care in Sweden, it needs to be further evaluated also with psychiatric patients suffering from severe PTSD. If therapist-guided internet delivered prolonged exposure would be found to effective, this project has the potential to be the first step towards implementation of a novel, superior and more cost-effective mode of treatment delivery for adults with PTSD in regular Swedish health care. The study is a single-blind, parallel-group superiority randomized controlled trial with 284 patients (142 per arm) that will compare therapist-guided internet delivered prolonged exposure with therapist-guided internet delivered cognitive-behavioral therapy The primary outcome is the blind-rater administered Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Secondary outcomes are cost effectiveness, mediators of change, dropout rate, and negative effects. The trial will also be preregistered at the Open Science Framework. Research questions to be answered are: 1. Is guided i-CBT with exposure more efficacious than an active control condition (therapist-supported internet-delivered psychoeducation, relaxation and support) in regard to reduction of blinded assessor rated PTSD symptom severity 1-month post-treatment? 2. Is guided i-CBT with exposure more cost-effective than an active control condition (therapist-supported internet-delivered psychoeducation, relaxation and support) in regard to reduction of blinded assessor rated PTSD symptom severity 1-month post-treatment? 3. Are the therapeutic gains of i-CBT maintained at long term follow up (6 and 12 months after treatment)? 4. Is guided i-CBT with exposure more efficacious than an active control condition (therapist-supported internet-delivered psychoeducation, relaxation and support) in regard to reduction in depressive symptoms and increase in quality of life up to 12 months after treatment completion? 5. What are the mediators of change in guided i-CBT for PTSD?