Procedures
pain, PTSD, ’
iCT-PTSD and iStress-PTSD were delivered online via a series of therapy modules with therapist support by messages within the online programme, SMS, and short weekly phone calls (designed to last on average 20 min) over the first 12 weeks (weekly treatment phase), and three monthly phone calls over the next 3 months (booster phase). Therapists could, with the participant's knowledge, read the information that they provided in the modules and write notes for them directly into the modules.The therapists were clinical psychologists experienced in providing face-to-face CBT. Therapists received training in the delivery of both online treatments and treated at least one person as a supervised training case with each treatment. Training involved familiarisation with the content of modules and the functionality of the programme and group supervision. There was no specified timeframe for training. Therapists received weekly group supervision for each of the treatment types to ensure adherence to protocol and to ensure high quality of treatment delivery. iCT-PTSD supervision was led by AE (expert in CT-PTSD), and iStress-PTSD supervision was led by AR (expert in stress management therapy). Therapists’ adherence to treatment components was assessed by independent raters (graduate psychologists) from a randomly selected audio recording of a whole phone call for each participant and the messages therapists sent via the online system for the week of this call. Treatment credibility (participant and therapist ratings)iCT-PTSD implements all procedures of cognitive therapy for PTSD, one of the trauma-focused CBT programmes recommended by NICE and international treatment guidelines.iStress is a stress-management therapy programme focusing on learning and practising a wide range of coping skills that have been shown to be efficacious with diverse groups experiencing stressors.Waiting list with usual clinical care involved 3 months of usual clinical care (general practitioner and other treating NHS services, eg, a stable dose of psychotropic medication, and treatment for pain and comorbid medical problems) while waiting for allocation to one of the internet-delivered treatments. Participants completed assessments at baseline (ie, at randomisation) and at 6 weeks and 13 weeks after randomisation. If participants no longer met PTSD criteria at 13 weeks, their participation in the trial was finished and they were offered treatment for residual symptoms.