, Volume 203, Issue 4, pp 745–752 | Cite as

Enhancement of suggestibility and imaginative ability with nitrous oxide

  • M. G. WhalleyEmail author
  • G. B. Brooks
Original Investigation



Imaginative suggestibility, a trait closely related to hypnotic suggestibility, is modifiable under some circumstances. Nitrous oxide (laughing gas) is commonly used for sedation in dentistry and is reported to be more effective when combined with appropriate suggestions.


The aim of this study was to determine whether nitrous oxide inhalation alters imaginative suggestibility and imagery vividness.


Thirty participants were tested twice in a within-subjects design, once during inhalation of 25% nitrous oxide and once during inhalation of air plus oxygen. Before the study, participants’ expectancies regarding the effects of nitrous oxide were assessed. Participants were blinded to drug administration. During each session, participants were verbally administered detailed measures of imagination and suggestibility: the Sheehan–Betts Quality of Mental Imagery scale and the Stanford Hypnotic Susceptibility Scale Form C, minus the hypnotic induction.


Imaginative suggestibility and imaginative ability (imagery vividness) were both elevated in the nitrous oxide condition. This effect was unrelated to participants’ expectations regarding the effects of the drug.


Nitrous oxide increased imaginative suggestibility and imaginative ability. Possible explanations of these findings are discussed with respect to the effects of N-methyl-d-aspartate antagonists and to other pharmacological effects upon suggestibility and imagination.


Suggestibility Nitrous oxide Imagination Imaginative ability Imagery Hypnosis Hypnotisability Suggestion Vividness NMDA 



The authors would like to thank David Oakley, Irving Kirsch, and Celia Morgan for their helpful comments during the preparation of this manuscript.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Hypnosis Unit, Department of PsychologyUniversity College LondonLondonUK

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