Being told what drug and effects to expect can change how people respond to nitrous oxide. Healthy volunteers could choose between inhaling nitrous oxide (10-40% concentration) or placebo (oxygen) after sampling both. One group was told the concentration and typical effects (tingling, euphoria, dysphoria); the other was only told the drug came from one of six classes. Thirty percent nitrous oxide was chosen more often than chance only by informed participants, and the probability of choosing 20-40% nitrous oxide was higher in the informed group. Subjective effects were unaffected, but psychomotor impairment at the highest concentration was greater in the non-informed group, suggesting that information can modulate reinforcing and impairing effects.
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.