Abstract
•The term ‘inhalants’ is used to cover a diverse group of drugs.•Population-level surveys use a range of definitions when measuring inhalant use.•Epidemiology will be improved by consistent terminology and definitions.•Nitrous oxide, volatile solvent, and alkyl nitrite use should be measured separately.
The term ‘inhalants’ is commonly used to describe a group of drugs that are characterised by the route of administration. There are three main sub-groups of inhalants; volatile solvents, alkyl nitrites, and nitrous oxide. These drugs all have different pharmacological properties, use patterns, and potential harms; yet they are sometimes grouped together in survey instruments. This critical review aimed to present a comparative analysis of how these inhalant drugs are defined, and use measured, across a range of population-level drug use surveys.
Population-level drug use surveys of youth (n=5) and general population (n=6), which measured use of at least once type of inhalant drug, were analysed as case studies. The types of inhalants surveyed were extracted, as well as definitions of these drugs, from code books or survey methods.
Differing definitions were used between surveys, and included differences between countries, and between surveys intended to measure youth and general population drug use. Of the six general population surveys; five reported nitrous oxide use, five reported volatile solvent use, and four reported alkyl nitrite use. Of the five youth-specific surveys; three reported volatile solvent use, whereas only one reported on alkyl nitrite use, and one reported nitrous oxide use.
There is no consistent approach used to define or measure the use of inhalant drugs, which has implications for global comparisons and understanding drug use in different populations. We conclude that the term ‘inhalants’ should be discontinued, due to the limited value in continuing to group very different types of drugs solely on the basis of their route of administration. Improving the epidemiology of volatile solvents, alkyl nitrites, and nitrous oxide as distinct drug types will be of benefit to harm reduction, treatment, and prevention efforts, and ensure these are targeted appropriately to population groups and context of use.