Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Proportion of people with PTSD
Systematic review	48 people Data from 1 RCT	Proportion of people meeting diagnostic criteria for PTSD 9/24 (38%) with group CBT 16/24 (67%) with waiting list control and usual care (combined analysis)	RR 0.56 95% CI 0.31 to 1.01		Not significant