Emergency department visits for gambling disorders doubled following the legalization of single-event sports betting and expansion of Ontario's online gambling market, according to a University of Toronto study. The increase was predominantly among young men.

Canada legalized single-event sports betting in August 2021. In April 2022, Ontario allowed private companies to operate in a regulated online gambling market. Ontario's market now includes 83 gaming and betting sites operated by 43 private companies. In 2024, Ontarians wagered $82.7 billion CAD through 2.6 million player accounts.

Researchers analyzed emergency department visits for gambling disorders among Ontarians aged 10 to 105 before and after the expansion. Over 14 years, 757 people had 952 emergency department visits where gambling disorder was the main or contributing reason. Almost three-quarters were male. By the end of the study period, visits were 154% higher than expected among males aged 10 to 29, and 116% higher among males aged 30 to 44. No changes occurred in females.

More than 70% of visits involved another mental health condition or heavy substance use, and almost one-third led to hospital admission. The findings were published in The American Journal of Preventive Medicine.