A Cochrane review included 15 trials, with number of participants ranging from 30 to 1 745. The quality of the trials was generally poor. Single session individual debriefing did not prevent the onset of post traumatic stress disorder (PTSD) nor reduce psychological distress, compared to control. At one year, one trial reported a significantly increased risk of PTSD in those receiving debriefing (OR 2.51 (95% CI 1.24 to 5.09). Those receiving the intervention reported no reduction in PTSD severity at 1–4 months (SMD 0.11, 95%CI 0.10 to 0.32), 6–13 months (SMD 0.26, 95% CI 0.01 to 0.50), or 3 years (SMD 0.17, 95% CI –0.34 to 0.67). There was also no evidence that debriefing reduced general psychological morbidity, depression or anxiety, or that it was superior to an educational intervention.
Comment: The quality of evidence is downgraded by imprecise results (the confidence limits for dichotomous outcomes are wide).