Legalization of sports betting in Ontario, Canada was linked to a rise in severe gambling-related health problems. That’s the conclusion of a new study published in the American Journal of Preventive Medicine .

Conducted by public health researchers at the University of Toronto covering January 2012 to June 2025, the study found that emergency-room visits for gambling disorders increased steadily—about 7% per quarter—eventually reaching 99% above expected levels by mid-2025. The increase built slowly, continued through the end of the study period, and was concentrated in males ages 10 to 44.

Researchers compared the number of ER visits they observed with the number that would have been expected had online gambling had not been legalized. By April-June 2025, visits were 99% higher overall, 154% higher for males ages 10–29, and 116% higher for males ages 30–44. And these cases weren’t mild; nearly one‑third of these ER visits resulted in hospitalization.

More than 70% of the visits involved another mental health condition or heavy substance use, with gambling disorder listed as the main or a contributing reason.

“This rise in severe presentations might be a bit of a warning signal of a wider increase in harms across the general population,” said study co‑author Ryan Forrest, a public‑health doctoral student at the University of Toronto, in an interview with Time magazine. He noted that ER data only shows the most extreme cases, and doesn’t capture financial problems, relationship strain, or worsening mental health that may also be happening.

A companion study published in the Canadian Medical Association Journal found parallel increases in contacts to ConnexOntario, the province’s 24‑hour mental‑health and addictions helpline. Gambling-related contacts doubled overall after April 2022. The biggest increases were among males ages 15–44—the demographic most aggressively targeted by online sportsbooks and casino apps—including a 317% rise among those ages 15–24.

“There’s two data sources telling us there is a real health signal happening here,” Forrest said.

The April 2022 launch of Ontario’s regulated private online gambling market followed Canada’s August 2021 federal change that allowed provinces to legalize single‑event sports betting. The shift triggered rapid expansion of online gambling platforms, aggressive advertising, and nonstop promotions—including “risk‑free” bets that critics say are anything but.