Nitrous oxide (more commonly known as laughing gas) is a widely used drug in the United Kingdom and many other European countries. This colorless, sweet-tasting gas has been used for over a hundred years recreationally and in medicine as an anesthetic and pain reliever.
Nitrous oxide is easy to obtain and relatively affordable, satisfying the two factors that drive drug consumption: price and availability. Short-acting effects include euphoria, a heightened sensation, and a slight feeling of disconnection from the body. It is inhaled through balloons or small bottles called “whippets.”
The drug is used by people of all ages, but young people make up the majority of those who report using it. Between 16 and 59 years old, 1.3% reported using nitrous oxide compared to 3.9% among those aged 16 to 24 years. As with all drug use information, it is difficult to be precise about the number of people using nitrous oxide and how often they use it. We know that some people will naturally be reserved when it comes to admitting drug use; for fear of being stigmatized and/or getting into trouble.
As with all medications, there are some risks associated with the use of nitrous oxide. It is these risks that have attracted widespread media attention over the past year. The UK government has responded to some doctors’ concerns about the possible harms of using nitrous oxide by updating legislation that makes possession of the drug a class C crime.
The use and supply of nitrous oxide was already restricted under the Psychoactive Substances Act, a topic discussed by Elf Professor Harry Sumnall in a previous Mental Elf blog.
Although most media attention has focused on health risks, such as neurological damage, there has been little discussion about the potential for addiction after use. Therefore, a recent review exploring this aspect by Back and colleagues (2023) is timely.
Nitrous oxide is easy to obtain and relatively affordable, satisfying the two factors that drive drug use: price and availability, but is it harmful to people who use it recreationally?
Methods
The authors conducted a literature review of studies that investigated recreational use of nitrous oxide rather than medical use. Nitrous oxide has been used medically as an anesthetic for over a hundred years.
This review of the available literature aimed to obtain information on how addictive the substance is when using the Diagnostic and Statistical Manual version 5 (DSM-5) criteria. This includes eleven elements such as tolerance to a drug, craving, and withdrawal symptoms. The DSM criteria are widely used in research and by doctors to evaluate individuals and their use of a medication or medications to establish whether a problem exists.
The authors included both human and animal studies in their literature search.
Results
After reviewing the literature and cross-checking against DSM-5 criteria, the authors concluded that nitrous oxide use met four of the eleven DSM-5 addiction criteria. The four were:
- Criterion 1: use more medication than intended.
- Criterion 3: Spend a considerable amount of time using the drug.
- Criterion 6: experiencing social or interpersonal problems.
- Criterion 8: potentially physically dangerous use.
It’s important to note that these were all for those who use nitrous oxide a lot, meaning frequently or at higher doses. Although the authors do not precisely define intensive use, they do mention that less than 3% of those who use the drug do so at least once a week, and the “most regular” users inhale 10 or more injections a day.
According to this review, regular users of nitrous oxide may meet some of the DSM-5 criteria for addiction.
Conclusions
The popularity of nitrous oxide has grown in recent years, as evidenced by the empty canisters littering many streets across the UK. The drug is often perceived to be harmless or at least low risk, except for the rarer cases of neurological damage that some people have experienced; however, its addiction potential is not well understood. This study makes this aspect the focus of its research.
The authors state that based on their findings, nitrous oxide should be considered addictive for heavy users of the drug, as it meets four of the eleven DSM-5 criteria. Although they do say that there are limitations with the studies they reviewed and included.
If we think about where nitrous oxide fits in the hierarchy of drug harms, it remains one of the least harmful of all widely used recreational drugs. The only sure way to avoid drug harm is to not use them in the first place, but that is neither an effective nor realistic approach, despite successive Governments base their drug policies and messages on that misconception.
Nitrous oxide has increased in popularity in recent years, but its addiction potential is still poorly understood.
Strengths and limitations
The authors are a little more candid about the limitations of the studies they found than about the problems with their own study. There is no mention or justification as to why they chose to conduct a literature search rather than a systematic review. The latter method is a more reliable and in-depth way of investigating the evidence.
As mentioned, some key aspects of their study are not clearly defined, such as what exactly is a “heavy” nitrous oxide user? Other important details are missing such as the inclusion and exclusion criteria used by the authors in their literature search.
It is also not useful to use the term addiction instead of physical or psychological dependence. It would have been a little more work, but it would have produced a more useful article if the authors had adopted this terminology and explored the topic in this more precise way.
There are many limitations to the studies included in this article that the authors describe. These include methods and sampling. For example, some studies were based on rats and many of the studies were qualitative or case-based. The authors rightly argue that larger cohort studies are needed to try to answer the question about the potential for nitrous oxide dependence.
On a more positive note, this article is timely and helps raise awareness about an aspect of nitrous oxide that has not received enough attention: its dependence profile. Crucially, the authors note that the risk of harm is greater for those who use the drug more frequently and at higher doses.
Future research should focus on the physical or psychological dependence that nitrous oxide users may experience, rather than the less specific term: addiction.
Implications for Practice
Given the limitations of the study and the literature on which it is based, it is still unclear what the addiction potential of this drug is. This clearly limits the doctor’s ability to advise anyone using the medication they encounter. This also restricts any public health messages or interventions that seek to reduce harm, given the limited information we have so far about the drug’s addictive potential.
Perhaps the best we can say at this time is that people who use nitrous oxide more frequently and in higher doses are at the highest risk of developing problems, whether physical or psychological. Frequency and dosage are factors that determine the potential harm caused by many drugs.
People who use nitrous oxide more frequently and in higher doses are at greater risk of developing problems, whether physical or psychological.
Declaration of interests
No conflicts of interest.
Links
primary job
Back, S., Kroon, E., Colyer‐Patel, K., & Cousijn, J. (2023). Does nitrous oxide addiction exist? An evaluation of the evidence for the presence and prevalence of substance use disorder symptoms in recreational nitrous oxide users. Addiction. https://doi.org/10.1111/add.16380
other references
Hamilton, I. Sumnall, H. Nitrous oxide: Suella Bravermans’ call to reclassify the drug has been rejected by government advisers, 2023. https://theconversation.com/nitrous-oxide-suella-bravermans-call-to-have-the-drug-reclassified-has-been-rejected-by-government-advisers-201265 The conversation.
Sumnall, H. Hamilton, I. Monaghan, M. New Psychoactive Substances: important information for health professionals. The mental elf, 3third March 2017 – https://www.nationalelfservice.net/mental-health/substance-misuse/novel-psychoactive-substances-important-information-for-health-professionals/
UK Government, 2023. Nitrous oxide: updated damage assessment https://www.gov.uk/government/publications/nitrous-oxide-updated-harms-assessment/nitrous-oxide-updated-harms-assessment-accessible
UK Home Office, 2023. Nitrous oxide ban: guidance. https://www.gov.uk/government/publications/nitrous-oxide-ban/nitrous-oxide-ban-guidance
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