Moderate drinkers chose nitrous oxide more often than light drinkers in a laboratory choice procedure, suggesting that alcohol history may influence the reinforcing effects of the drug. Healthy volunteers sampled placebo and 10-40% nitrous oxide across four sessions and then chose between the two. Most subjective and psychomotor-impairing effects did not differ between the groups. However, moderate drinkers selected nitrous oxide a median of three times, compared with one time for light drinkers, a statistically significant difference. The findings provide suggestive evidence that prior alcohol exposure modulates how rewarding nitrous oxide is.
Brief exposures (about 1.5 minutes) to nitrous oxide at concentrations of 20-80% in oxygen did not function as reinforcers in 11 healthy volunteers with modest lifetime psychoactive drug use. In a choice procedure, subjects sampled each concentration and placebo oxygen, then chose between them. 20%, 40%, 60%, and 80% nitrous oxide were chosen by five, four, three, and three subjects respectively, none exceeding chance levels. All concentrations produced psychoactive effects, with concentration-related subjective effects. The authors conclude that nitrous oxide inhaled in a manner similar to recreational use does not act as a reinforcer across a wide range of concentrations in this population.