Doctors have sounded the alarm over a rise in cases of nerve damage linked to the use of nitrous oxide.
In recent years, nitrous oxide – commonly known as “nos” – has become a hugely popular recreational drug. It has reportedly been widely used at festivals this summer.
In the 2019-20 Crime Survey for England and Wales, almost 9% of 16- to 24-year-olds said they had taken nitrous oxide in the last year, up from 6.1% in 2012-13.
Experts say that as use of the drug has risen, so too have cases of spinal cord and nerve damage, including paralysis.
“There is no doubt that we have seen an increase of cases, as this was almost unknown last year and now [we] see cases weekly,” said Dr Nikos Evangelou, an academic neurologist at the University of Nottingham.
Writing on Twitter, Evangelou described the situation as an epidemic, adding: “Terrifying to see paralysed young people from laughing gas canisters.”
Dr David Nicholl, a neurologist at Sandwell and West Birmingham NHS trust, also called the problem an epidemic in a recent TikTok video.
“We’re seeing dozens of young people coming into hospital because they’re off their legs; some of them have life-changing neurological injuries,” he said.
Discovered by the chemist Joseph Priestley in 1772 – and subsequently the subject of myriad experiments and cartoons – nitrous oxide became a useful tool in medical settings to treat severe pain.
While it can induce laughter and hallucinations, it can also cause neurological problems by inactivating the vitamin B12.
“B12 is crucial in the production of myelin, which is the fatty sheath around nerves in your body,” said Dr Trevor Pickersgill, a consultant neurologist at Cardiff and Vale University Health Board. When B12 is inactivated by nitrous oxide, myelin is no longer kept in good repair. “That causes spinal cord damage, which can be irreversible if untreated,” said Pickersgill.
Dr Mark Ellul, a specialist registrar in neurology based in Liverpool, said cases of nerve damage from nitrous oxide use were frequent. “I’d say as a unit we probably see a case every few weeks,” he said. “Most are young people, and many were previously unaware that the substance could be harmful. In some cases the effects can be quite severe and long-lasting.”
One study carried out by researchers in Strasbourg reported that five patients were admitted to a tertiary care centre between April 2020 and February 2021 with rapidly progressive neurological symptoms after using nitrous oxide.
“When I did a retrospective analysis of all patients admitted in 10 years prior to April 2020, not a single patient had been diagnosed with neurological complications due to nitrous oxide abuse at our hospital,” said the lead author, Maximilian Einsiedler.
While it is illegal in the UK to supply nitrous oxide for human consumption or to sell it to children, it is not illegal to possess the drug. Users often buy small silver canisters of the gas – known as whippits because of their original purpose as whipped cream chargers – and inhale it from a balloon.
However, there are concerns that large canisters of the gas are becoming more common, with giant containers 80 times the size of whippits found in the streets of London after the Notting Hill carnival this weekend.
Harry Sumnall, a professor in substance use at Liverpool John Moores University, said there was a lack of hard data on the prevalence of serious problems resulting from nitrous oxide use in the UK.
While Sumnall said that even a relatively small rise in cases from a low baseline was of concern to neurologists, he said the people most at risk of significant complications were those exposed to high quantities of the gas.
“Just to put it into perspective, [there are] more than 600,000 users in the UK, and most people if they are using it are going to be using it a few times a year, at really low levels of risk,” he said.