Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Proportion of people developing PTSD
RCT	152 people with psychological distress after physical injury, 116 followed up at 13 months (per protocol analysis)	Proportion of people meeting DSM-IV criteria for PTSD 13 months 10/61 (16%) with CBT (4 sessions between 5 and 10 weeks after the injury) 15/55 (27%) with no psychological intervention	RR 0.6 95% CI 0.3 to 1.5		Not significant
Symptoms that may lead to a diagnosis of PTSD
RCT	132 bus drivers who had been attacked in the previous few days	Improvement in measures of anxiety (assessed using Horowitz scale; change in mean score from baseline) 6 months from 7.4 to 6.2 with CBT (1 to 6 sessions) from 7 to 6.9 with standard care	Significance not assessed
RCT	132 bus drivers who had been attacked in the previous few days	Improvement in intrusive symptoms (change in mean score from baseline) 6 months from 10.9 to 7.7 with CBT (1 to 6 sessions) from 7.2 to 4.7 with standard care	Significance not assessed
RCT	132 bus drivers who had been attacked in the previous few days	Improvement in measures of depression (change in mean score from baseline) 6 months from 3.6 to 3.2 with CBT (1 to 6 sessions) from 3.6 to 3.3 with standard care	Significance not assessed
RCT	132 bus drivers who had been attacked in the previous few days	Improvement in avoidance symptoms (change in mean score from baseline) 6 months from 11 to 9.5 with CBT (1 to 6 sessions) from 8.4 to 7.3 with standard care	Significance not assessed
RCT	152 people with psychological distress after physical injury, 116 followed up at 13 months	Mean reduction in severity of PTSD symptom score (assessed using the Impact of Event Scale) 13 months 20.7 with CBT (4 sessions between 5 and 10 weeks after the injury) 11.2 with no psychological intervention	Adjusted mean difference 8.4 95% CI 2.4 to 14.4	Effect size not calculated	CBT