The progression of Ms Caldwell’s addiction – from youthful misuse to life-threatening compulsion – has become increasingly common. The Annual Report of America’s Poison Centers found there was a 58 % increase in reports of intentional exposure to nitrous oxide in the US between 2023-2024.

In a worst-case scenario, inhalation of nitrous oxide can lead to hypoxia, where the brain does not get enough oxygen. This can result in death. Regular inhalation can also lead to a Vitamin B12 deficiency which can cause nerve damage, degradation of the spinal column and even paralysis. The number of deaths attributed to nitrous oxide poisonings rose by more than 110% between 2019 and 2023, according to the Centers for Disease Control and Prevention.

Until recently users would take single-use plain metal canisters weighing around 8g and inhale the gas using a balloon. But when usage spiked during the pandemic, nitrous oxide manufacturers began selling much larger canisters online – as large as 2kg – and, eventually, in shops selling electronic vapes and other smoking paraphernalia.