Internet-delivered cognitive behaviour therapy for post-traumatic stress disorder: a randomised controlled trial and outcomes in routine care

Background: Despite its potential scalability, little is known about the outcomes of internet-based cognitive behaviour therapy (iCBT) for post-traumatic stress disorder (PTSD) when it is provided with minimal guidance from a clinician. Aim: To evaluate the outcomes of minimally guided iCBT for PTSD in a randomised control trial (RCT, Study 1) and in an open trial in routine community care (Study 2). Method: A RCT compared the iCBT course (n=21) to a waitlist control (WLC, n=19) among participants diagnosed with PTSD. The iCBT group was followed up 3 months post-treatment. In Study 2, treatment outcomes were evaluated among 117 adults in routine community care. PTSD symptom severity was the primary outcome in both studies, with psychological distress and co-morbid anxiety and depressive symptoms providing secondary outcomes. Results: iCBT participants in both studies experienced significant reductions in PTSD symptom severity from pre- to post-treatment treatment (within-group Hedges' g=.72-1.02), with RCT findings showing maintenance of gains at 3-month follow-up. The WLC group in the RCT also significantly improved, but Study 1 was under-powered and the medium between-group effect favouring iCBT did not reach significance (g=0.64; 95% CI, -0.10-1.38). Conclusions: This research provides preliminary support for the utility of iCBT for PTSD when provided with minimal clinician guidance. Future studies are needed to clarify the effect of differing levels of clinician support on PTSD iCBT outcomes, as well as exploring how best to integrate iCBT into large-scale, routine clinical care of PTSD.