There has never been published a randomised controlled trial of group debriefing. In this study we employed an analogue study with students to conduct the first such trial. Sixty-four participants were shown a stressful video of paramedics attending to injured and dead victims of a road traffic accident. Half the participants were subsequently debriefed and half were provided with tea and biscuits and allowed to talk amongst themselves. A 1 month follow-up was administered. It was found that, while the video was rated as distressing, there were no significant differences between the debriefed and non-debriefed groups on measures of affective distress and trauma symptoms. Those who were debriefed later recalled having wanted to talk more to someone about the video than those who were not debriefed. It is suggested that cognitive dissonance may explain this result.