Brom 1993.

Methods	Design: RCT
Participants	Setting: Participants were recruited from police records of MVA and seen on an outpatient basis. Type of trauma exposure: MVA Inclusion criteria: exposure to an MVAs of moderately serious‐to‐serious severity Exclusion criteria: not specified Sample size: 738 people randomised and written to by the police and invited to take part in study; 151 agreed to take part in the study; 83 (36%) agreed to take part in the monitoring group and 68 (13%) took up the offer of intervention. Mean age: 37.6 (SD 16.6) years Gender: 89 (58.9%) men; 62 (41.1%) women Ethnicity: not reported Country: Netherlands
Interventions	Group 1: counselling intervention: n = 68 Counselling intervention lasted 3–6 sessions depending on need. Components of the intervention included: practical help and information on procedures following an MVA and general information about psychological reactions; support to recognise that the event was over, to explore the experience and related emotions and to mobilise support networks; reality testing and confronting emotional reactions; confronting the memory of the experience; ongoing contact at least 2–3 months after the accident; referral for psychotherapeutic treatment where indicated. Group 2: monitoring group: n = 83 Monitoring group were unaware that they were part of a comparison study and received assessments only.
Outcomes	PTSD: IES Other: Trauma Symptom Inventory Follow‐up: 1 and 6 months
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not reported but outcomes were likely to be measured by the therapists.
Incomplete outcome data (attrition bias) All outcomes	High risk	The plan of analysis and management of dropout is not reported.
Selective reporting (reporting bias)	Unclear risk	No study protocol identified.
Other bias	High risk	Randomisation occurred prior to potential participants agreeing to take part in the study and participants were only aware that they were either invited to participate in a secondary prevention programme or that they were invited to participate in a research project. The response rate for the monitoring group was 36%, for the intervention group 13%. Symptom scores on the IES were not matched at baseline. Groups were not matched for marital status and income. Individuals in the monitoring group were more likely to be married and had a statistically significant higher level of income.