Decision-making behaviour during inhalation of subanaesthetic concentrations of enflurane

The effect of subanaesthetic concentrations of enflurane on decision-making behaviour in risk situations was assessed using a signal detection task. The subject heard noise alone (white noise) or a signal superimposed on the noise (1000-Hz tone) and had to report what he heard in each trial. Risk situations were manipulated by changing the monetary reward and penalty associated with correct and incorrect responses. Eight male volunteers participated in this study. It was found that under anaesthetic influence they did not avoid the same risks which had been avoided under control conditions. The findings are explained in terms of influence of the gas on loss of control and lessened responsibility for the result of behaviour.