Suicide deaths by gas inhalation in Toronto, Canada-an observational study of emerging methods of suicide from 1998 to 2020.

Background: Inert gases are an emerging means of suicide in Toronto, Canada. Trends in suicide by these methods change over time, yet long-term patterns remain uncharacterized in cities like Toronto. Aims: To update trends in suicide using inhalational gas and explore the profiles of individuals using different methods in Toronto. Methods: Suicide deaths were identified from coroner’s records and classified by suicide methods. Time trends were explored, and bivariate analyses were performed to characterize differences in profiles between groups. Results: There were 229 suicide deaths by inert gas between 1998 and 2020. For 2016–2020, suicide by nitrogen increased by 100%, whereas there was a decrease in suicide by helium (38%) and charcoal burning (57%) compared to 2011–2015. Males comprised a higher proportion of inhalational gas deaths compared to other methods. Individuals who died by compressed gas and charcoal burning were more likely to have left suicide notes compared to people who died by other methods. Limitations: The number of suicide deaths by gas inhalation may be underestimated due to potential misclassification. Conclusions: Suicide prevention strategies including restricting access to suicidal means, providing helpline information on the products, and responsible media reporting should each be advocated for.