Within- and between-subject variability in the reinforcing and subjective effects of nitrous oxide in healthy volunteers.
Drug and alcohol dependence September 1, 2001 DOI: 10.1016/s0376-8716(00)00234-9 via PubMed
Summary
AI-generated from the abstractThe reinforcing and subjective effects of nitrous oxide varied more between people than within the same person across sessions. Twelve volunteers without drug dependence inhaled 30% nitrous oxide or 100% oxygen for 10 minutes each, then chose between the two or drug-free air nine times per session. Choice differed across subjects but stayed stable within subjects. Some subjective effects correlated with choice and differed between consistent choosers of nitrous oxide and non-choosers, but drug liking and euphoria—standard measures of abuse liability—were unrelated to choice. Subjective effects fluctuated across sessions more than reinforcing effects did, underscoring the need for multiple measures when assessing abuse liability.
Study at a glance
| Characteristics | Within-subjects experimental study Peer reviewed |
|---|---|
| Sample size | 12 |
| Population | Volunteers with no history of drug dependence |
| Intervention | 100% oxygen |
| Dose | 30% N2O |
| Duration | Five sessions, each with 10-minute sampling and nine choice trials every 5 minutes |
| Key finding | Individual differences in subjective and reinforcing effects of nitrous oxide were larger than within-subject variability, and drug liking and euphoria were unrelated to choice. |
Abstract
Within- and between-subject variability in the reinforcing and subjective effects of nitrous oxide (N(2)O) was studied across five sessions. Twelve volunteers with no history of drug dependence sampled 30% N(2)O and 100% oxygen for 10 min each, then chose nine times, once every 5 min, among N(2)O (e.g. "Agent A"), oxygen (e.g. "Agent B"), or "drug-free air." Choice varied across subjects but was stable within subjects. Quantitative differences in subjective effects occurred within and across subjects. Some subjective effects were correlated with choice and/or differed between subjects who were consistent choosers of N(2)O versus those who were not. However, drug liking and euphoria, two face-valid measures of abuse liability, were unrelated to choice. Thus, the present study found individual differences (i.e. between-subject variability) in subjective and reinforcing effects of N(2)O and, in terms of within-subject variability, suggested that subjective effects fluctuate across sessions to a relatively greater extent than do reinforcing effects. The varying degrees of correlation between N(2)O choice and its subjective effects emphasize the need for obtaining multiple measures when characterizing abuse liability of this drug.