Mini-Review: A Brief History of Nitrous Oxide (N2O) Use in Neuropsychiatry
M. Gillman
Current Drug Research Reviews June 1, 2019 DOI: 10.2174/1874473711666181008163107 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Historical analysis Peer reviewed |
|---|---|
| Intervention | Nitrous oxide |
| Key points | The paper traces the history of nitrous oxide in psychiatry, from 18th-century recognition of its psychotropic actions through anaesthetic-era neuropsychiatric research (1920-1950), the adoption of low-dose dental titration in the early 1980s for psychiatric conditions including substance abuse, and the 1994 introduction of the term Psychotropic Analgesic Nitrous oxide (PAN). The authors conclude that the role of non-opioid systems in N2O's psychotropic properties remains to be established. |
Abstract
Background: Joseph Priestley’s discovery of nitrous oxide (N2O) was recorded in 1772. In the late 1790’s, Humphry Davy experimented with the psychotropic properties of N2O, describing his observations in a book, published in 1800. A dentist, Horace Wells discovered anaesthesia with N2O in 1844. Over a century after Davy, its potential usefulness in psychiatry was first recognised. The seminal researches in neuropsychiatry, between 1920 and 1950, mainly used anaesthetic concen-trations of the gas. The psychotropic actions of N2O, at non-anaesthetic doses, were first used by den-tists, mainly for its anxiolytic action. In modern dentistry, N2O is always mixed with at least 30% ox-ygen and titrated to doses rarely exceeding 40% of N2O. At these lower concentrations, untoward ef-fects are almost always avoided, including over-sedation and/or anaesthesia. In the early 1980’s, the low-dose dental titration technique was first used to investigate and treat psychiatric conditions, includ-ing substance abuse. Until then, most physicians regarded the gas only as an anaesthetic agent. An ex-ception was obstetricians who used a fixed 50% concentration of N2O diluted with oxygen for analge-sia during parturition. In 1994, to clearly distinguish between anaesthetic and non-anaesthetic concen-trations (as used in dentistry), the term Psychotropic Analgesic Nitrous oxide (PAN) was introduced.
Objective: This paper will give a brief history of the use of the N2O in psychiatry since the psycho-tropic actions were first recognised in the 18th century until the present.
Conclusion: The role of other non- opioid systems, and the extent to which they contribute to the psy-chotropic properties of N2O, still remains to be established.