Mouthaan 2013.

Methods	Design: RCT
Participants	Setting: 2 level 1 trauma centres Type of trauma exposure: injury patients transported by ambulance or helicopter. Suspected to have experienced possible severe injuries that required specialised acute medical care. Inclusion criteria: aged ≥ 18 years, proficiency in Dutch and having experienced a potential traumatic event (cf. Criterion A1 DSM‐IV PTSD diagnosis). Exclusion criteria: injury resulting from deliberate self‐harm; organic brain condition, psychotic disorder, bipolar disorder or depression with psychotic features; moderate‐to‐severe traumatic brain injury or permanent residency outside the Netherlands. Sample size: 1807 individuals considered; 1032 assessed for eligibility and 300 randomised Mean age: self‐guided Internet‐based intervention: 44.18 (SD 15.76) years; no intervention: 43.49 (SD 16.00) years Gender: 180 (60%) men; 120 (40%) women Ethnicity: not reported. 249 (83%) reported to be of Dutch cultural background. Country: Netherlands
Interventions	Group 1: self‐guided Internet‐based intervention: n = 151 Based on established CBT techniques (Trauma TIPS, which is based on CBT techniques of psychoeducation, stress management/relaxation techniques and in vivo exposure). It consists of 6 steps, including introduction to the programme and basic operating instructions; assessments of acute anxiety and arousal using VAS at pre‐ and postintervention; video features of the trauma centre's surgical head explaining the procedures at the centre and the purpose of the programme, and of 3 patient models sharing their experiences after their injury; a short textual summary of 5 coping tips for common physical and psychological reactions after trauma; audio clips with instructions for stress management techniques; contact information for program assistance or professional help for enduring symptoms; and a Web forum for peer support. Group 2: TAU: n = 149 Care as usual, available to patients from both groups, consisted of incidental, non‐structured talks with trauma centre staff or with a patient's general practitioner (GP), either directly following injury or during the course of the trial.
Outcomes	PTSD: CAPS; IES‐R Other: HADS; MINI‐Plus, version 5.0 to diagnose major depressive disorders and other anxiety disorders; mental healthcare utilisation using the Trimbos/Institute for Medical Technology Assessment questionnaire and the Short Form Health and Labour Questionnaire. Follow‐up: 1, 3, 6 and 12 months' postinjury
Notes	The authors noted that participants were reluctant to use the intervention.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation performed by a research member independent of data collection in a 1:1 ratio by a computerised program using random block sizes stratified by study centre.
Allocation concealment (selection bias)	Low risk	Randomisation performed by a research member independent of data collection in a 1:1 ratio by a computerised program using random block sizes stratified by study centre.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Patients were asked not to share information about the randomisation to the assessors, to ensure that they were blind to the allocated interventions.
Incomplete outcome data (attrition bias) All outcomes	Low risk	ITT and completer‐only analysis was undertaken using mixed‐model analysis. Modest loss to follow‐up at 1 and 3 months. However, missing data > 50% at 6 and 12 months.
Selective reporting (reporting bias)	Low risk	Outcomes were as reported in the study protocol.
Other bias	High risk	Authors affiliated with experimental intervention.