Internet-delivered cognitive behavioural therapy for post-traumatic stress disorder: systematic review and meta-analysis.

While the review found some beneficial effects of i-CBT for PTSD post-treatment, the quality of the evidence was very low because of the small number of included trials and there was insufficient evidence to support the maintenance of improvement at follow-up of 3-6 months. Further work is required to establish non-inferiority to current first-line interventions; to determine long-term efficacy; to explore mechanisms of effect; and to establish optimal levels of guidance.