How a Bachelor's thesis on laughing gas led to a scientific publication

They were sold at every festival and in clubs: balloons filled with laughing gas. Party-goers used the balloons en masse to experience a brief euphoric high. The nitrous oxide canisters are intended for whipped cream dispensers, but recreational use skyrocketed in the last decade. Users often think its use is harmless, but this perception changed as problematic use became increasingly evident. Not only did people become paralysed, users also got behind the wheel, with all the ensuing consequences. Trading in canisters proved to be a lucrative business, with the Amsterdam Laughing Gas King as a notable example.

Problematic Use

The sale for recreational use in the Netherlands has been banned since January 2023. According to former student Sammie Back and university associate professor of clinical psychology Janna Cousijn, a good move. Back wrote her bachelor's thesis on whether laughing gas is addictive under the supervision of Cousijn. "At that time, the perception among students was that it was safe and non-addictive," says Back. Yet, users were showing up in addiction clinics, raising questions. "Some users unsuccessfully tried to stop or keep increasing their use. There are also known cases of people using hundreds of balloons for days on end. This can lead to physically dangerous situations and major social problems."

Scientific Publication

The thesis shows that nitrous oxide use could indeed be addictive and that it is not as harmless as often thought. Cousijn saw great potential in the study, and eventually, it led to a scientific publication in the Journal of Addiction. Sammie was also interviewed for a podcast series by the leading journal. "Sammie wrote a paper in eight weeks, which would be difficult for an average PhD student. I myself took nine months to write my first paper," says Cousijn. "What I find particularly clever is that she looked very broadly into the literature and included many different disciplines. An undergraduate thesis normally focuses on one aspect, but this paper is very comprehensive and also very socially relevant."

In the widely used diagnostic manual for psychiatry (DSM 5), eleven criteria of addiction are included. The paper aimed to see if laughing gas users experiences similar criteria and how often they occur. Although there is no evidence for physical dependence (as with alcohol and cocaine), there does seem to be evidence for psychological dependence among laughing gas users. "We found evidence for four of the eleven addiction criteria and had strong indications for some others. That is an important finding. At the same time, the low number of studies is very striking. It was really scraping by, and so I even looked at animal studies."

Research and Practice

Sammie Back is now training as a psychologist in an addiction clinic. Her interest in addiction care grew during her master's in clinical psychology. What appealed to her about the master is that neuroscience is combined with research into the role of environmental factors: "I think it's great that I can now bring my academic background into practice. I will possibly do research again later, but then I would like to do it with knowledge of clinical practice."

Laughing gas is increasingly being banned in more countries. Recently, a new law came into effect in the United Kingdom. Is it still necessary to demonstrate that laughing gas is addictive? "Definitely," says Cousijn, "We are looking at the whole world, and recreational use of laughing gas is still allowed in many places. We want to protect the health of everyone."

In the media

Interview AD with Sammie Back