Kuhn 2017.

Study characteristics
Methods	Randomised controlled trial
Participants	Sample size: 120 Diagnosis: DSM‐IV PTSD Method of recruitment: advertisements through fliers, media coverage, social media and websites (Craigslist) Method of diagnosis: PCL‐C Trauma type: various Age (mean): PTSD Coach: 39.43 (SD 15.16) years; wait list: 39.12 (SD 14.08) years Sex: 69.2% women, 30.8% men Location: US Comorbidities: not reported Adjunctive therapy: not reported Adjunctive medication: not reported Unemployment: not reported University education: 14.2% Exclusion criteria: currently receiving treatment for PTSD Baseline PTSD: all participants met diagnostic criteria for PTSD (no participant had a PCL score < 35). Baseline PCL scores (mean): for PTSD Coach: 63.19 (SD 11.78); wait list: 60.59 (SD 10.24)
Interventions	Internet programme based on trauma‐focused CBT versus wait list Experimental arm Duration: 12 weeks Treatment protocol: PTSD Coach PTSD Coach condition participants were instructed to download the app and use it however they would like in an attempt to mimic real use. They were e‐mailed links to the post‐treatment assessment 3 months later and follow‐up assessment 6 months. Comparator arm Duration: 12 weeks Treatment protocol: wait list Wait list participants received no intervention during the treatment period. After the post‐treatment assessment, they were told that the app being studied was PTSD Coach, that the app was available in the App Store and Google Play Store, and that they were now free to download and use it if they would like. They were e‐mailed links to the post‐treatment assessment 3 months later and follow‐up assessment 6 months.
Outcomes	Time points for assessment: 3 and 6 months Primary outcome: PCL Secondary outcome: PTSD symptom coping self‐efficacy, PHQ‐8 and B‐IPF
Notes	Funding source: not reported Declarations of interest among the primary researchers: none
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "randomized to conditions by the study coordinator using adaptive randomization, with the probability of condition assignment changing based on the assignment of participants already in the trial using www.randomizer.com."
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Impossible to blind participants or therapists.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: self‐reported measures.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Following the intent‐to‐treat principle, data from all randomized participants were analyzed, and multiple imputation was used to replace missing values, with 10 imputed data sets being generated."
Selective reporting (reporting bias)	Low risk	Study protocol not available but it was clear that the published reports included all expected outcomes, including those that were prespecified.
Other bias	Low risk	Study appeared free from other sources of bias.