Effects of nitrous oxide on decision-strategy and sustained attention.

Effects of 10,20, and 30% N2O on decision-making strategy, reaction-times, sustained attention, the Digit Symbol Subsititution Test (DSST), short-term memory and the Clyde Mood Scale were assessed in 12 test subjects. Decision-making strategy, as measured by 2-choice probability-learning, was unaffected by 30% N2O once a strategy had been formulated, but reaction-times were increased. Sustained attention was significantly affected in 33% of our subjects, whereas performance on the DSST and on the short-term memory task was impaired in virtually all subjects. Changes were noted in several mood-scale factors with 30% N2O. No residual drug effects were found.