A comparative study of the harms of nitrous oxide and poppers using the MCDA approach

Summary

Nitrous oxide (laughing gas) and alkyl nitrites (poppers) rank among the least harmful recreational drugs when assessed on 16 criteria including dependence, injury, and economic cost. An expert panel using Multi-Criteria Decision Analysis scored nitrous oxide at 6 and poppers at 5 on a 0–100 overall harm scale, placing them just above magic mushrooms (psilocybin). Nitrous oxide scored higher for dependence, environmental damage, mental impairment, and family adversities; poppers scored higher for injury, drug-related damage, economic cost, and mortality. The findings aim to inform UK policy decisions, as nitrous oxide possession is not currently controlled under the Misuse of Drugs Act.

Study at a glance

Abstract

The recent surge in recreational (non-medical) use of nitrous oxide (N 2 O, also known as ‘laughing gas’) often by inhaling it from balloons, has attracted the attention of some politicians with calls to control its possession under the United Kingdom (UK) Misuse of Drugs Act 1971 (currently selling, but not possession, for recreational use is controlled under the Psychoactive Substances Act 2016). Meanwhile, the recreational use of nitric monoxide (NO) as delivered by alkyl nitrites, also known as ‘poppers’ has also raised concerns, but unlike N 2 O, its use was not controlled under the 2016 Act. To inform future-decision making processes and ensure that any such decisions are based on the best evidence, Drug Science conducted a Multi-Criteria Decision Analysis (MCDA) about N 2 O and poppers to compare the overall harms of these two drugs to the harms of 20 drugs previously evaluated and published by Nutt et al. The group assessed harm scores for N 2 O and poppers on the original 16 harm criteria using the associated 0 to 100 scales, on each of which 100 had been assigned to the most harmful drug and zero to the least harmful, though that often meant no harm. On the overall harm scale, N 2 O scored 6, just above magic mushrooms (psilocybin) while ‘poppers’ scored 5. Together these are the three lowest drugs on the overall harm scale. Although their overall scores are similar, the reasons behind the ratings differ. Nitrous oxide was considered more harmful than poppers for Dependence, Environmental Damage, Drug Related Relative Impairment of Mental Functioning, and Family Adversities, while poppers are more harmful than N 2 O for Injury, Drug Related Damage, Economic Cost, and Drug Related Mortality. When assessing the risk different substances may hold when making policy decisions, it is important to acknowledge the relative contribution of these diverse harms within different domains.