Has there been an increase in nitrous oxide use and associated harms in Australia? An analysis of triangulated data sources, 2003–2020.

• There has been growing concern, globally, regarding use of nitrous oxide (N 2 O). • Use, google search probabilities and social media posts increased from 2009 and 2020. • Sharpest increases were noted between 2015 and 2018, plateauing in recent years. • Frequency and quantity of N 2 O use remained stable and low. • Number of N 2 O-related calls to Poisons Information Centres increased sixfold. There is growing concern, globally, regarding use of nitrous oxide (N 2 O) for intoxication purposes. This paper aims to examine trends in: (i) past six month N 2 O use among a sample of people who use regularly use ecstasy and/or other illicit stimulants (2003–2020); (ii) volume of N 2 O-related Google searches and social media posts (2009–2020); and (iii) N 2 O-related calls to Poisons Information Centres (PIC) (2004–2020). Data were obtained from annual interviews with sentinel samples of Australians aged ≥16 years who used ecstasy and/or other illicit stimulants ≥monthly and resided in a capital city (∼800 each year); Google search activity; social media posts; and exposure calls to four PIC. Among samples of people who regularly use ecstasy and/or other illicit stimulants, past six-month N 2 O use increased 10% each year from 2009 to 2020, with the sharpest increase observed between 2015 and 2018 (25.4% p/year; 95% CI: 14.6–37.1). Frequency and quantity of N 2 O use remained stable and low. Google search probabilities increased by 1.8% each month from January 2009 and December 2019 (95% CI: 1.5–2.2), with the sharpest increase observed between July 2016 to December 2017 (6.0% p/month; 95% CI: 4.4–7.5). Social media posts increased 2.0% per month from January 2009 and December 2019 (95% CI: 1.1–3.0), with the sharpest increase observed between March and October 2017 (19.2% p/month; 95% CI: 1.7–39.7). The number of N 2 O-related calls to Australian PIC increased sixfold between 2016 (16) and 2020 (111). Triangulation of various data sources indicate significant shifts in N 2 O use and harms in Australia. This includes increases in use, Google searches and social media posts, although these have plateaued in recent years, coupled with increased rates of harm. These findings correspond with evidence of a global increase in N 2 O use and harm, highlighting the need for education of both people who use N 2 O and health professionals. [ABSTRACT FROM AUTHOR]