Gambling Disorder ER Visits Nearly Doubled After Ontario Opened Online Betting. The Increase Was Almost All Young Men.

A public health experiment has been running north of the border for four years, and the emergency room is where its results are showing up.

When Canada legalized single-event sports betting in August 2021, and Ontario followed in April 2022 by letting private companies operate online gambling platforms alongside the government's own, the province became the largest regulated iGaming market in North America almost overnight. By 2024, Ontarians had wagered 82.7 billion Canadian dollars across 83 licensed sites run by 43 private operators, using 2.6 million player accounts.

A new study in the September issue of the American Journal of Preventive Medicine traced what happened to the province's emergency departments over those years. The short version: visits for gambling disorder climbed far beyond what population trends predicted, and the rise landed with unusual precision on young men — the group the online betting industry markets to hardest.

A Market, Then a Doubling of Emergency Visits

The research team, based at the Institute for Clinical Evaluative Sciences (ICES) in Ontario, drew on health administrative data covering a 14-year window — long enough to establish a pre-expansion baseline and then watch it bend. Across that span they identified 757 people who accounted for 952 emergency department visits in which a gambling disorder was recorded either as the main reason for the visit or as a contributing factor. Close to three-quarters of those patients were male.

The absolute numbers are modest: a few hundred people in a province of roughly 16 million. That is the point the authors make rather than avoid. Gambling disorder sends people to hospital rarely and late. The signal worth reading is the shape of the curve, not its height.

And the curve bent sharply at exactly the moment the authors would expect. Measured at the end of the study period, observed visits were 154 percent higher than expected among males aged 10 to 29, and 116 percent higher than expected among males aged 30 to 44. Among females, the study found no detectable change at all.

Why "Expected" Is Doing Real Work Here

The comparison is not against the start of the study — it is against a counterfactual. The team modeled what visit counts should have looked like given the population's size, age structure and underlying trends, then compared observed against predicted. That design blunts the obvious objection that emergency visits rise for every reason over time. It does not, on its own, prove that legalization caused the increase; nothing short of a randomized trial could. But the timing, the demographic specificity, and the absence of any comparable shift in women make a coincidental explanation harder to defend.

The authors also brought corroborating evidence. The same team had already documented a substantial increase in gambling-related contacts to ConnexOntario, the province's mental health and addiction helpline, after the market expanded — but hedged that finding, because operators and advertisers are required by law to display the helpline number. Emergency departments carry no such promotion. In that sense, the ER data test the helpline result rather than simply repeat it.

Stigma Hides the Real Denominator

If the study contains one sentence that ought to be read twice, it is this one, from senior author Daniel Myran, a physician and scientist at ICES and an associate professor in the University of Toronto's department of family and community medicine.

"Most people experiencing gambling problems will never seek care, so the concern is that the increases in ED visits for gambling disorders we observed may be revealing much larger increases in gambling-related harm."

That is the structural problem with measuring behavioral addiction. Alcohol and opioid crises leave chemical traces in toxicology panels and death certificates. Gambling leaves bank statements and sleepless nights. People arrive at hospitals only after the damage has compounded, which is why prior research has consistently found that those who do seek help typically do so only once health and social harms are already severe.

Wait times, triage priorities and stigma all push in the same direction. A person in the middle of a gambling crisis is unlikely to describe it as the reason for their chest pain, and an emergency clinician has roughly ten minutes to find out.

Nearly a Third of These Visits Ended in Admission

The clinical picture those late arrivals present is not simple, and the study's severity data is easy to skim past. More than 70 percent of the gambling-disorder emergency visits involved another mental health condition or heavy substance use. Nearly a third ended in a hospital admission — a high bar for an emergency department that sends most psychiatric and substance-related presentations home with a referral.

That pattern matches what clinicians see in dual diagnosis care, where disordered gambling, depression, anxiety and alcohol use tend to arrive together and reinforce one another. A betting loss drives drinking; the drinking erodes sleep and mood; the mood drives another attempt to win it back. Treating only the gambling in that loop tends to send the patient back out with the other half intact.

What the Study Cannot Tell Us

Administrative data has limits, and the paper's own framing is worth taking at face value.

Diagnosis codes capture what a clinician recorded, not everything a patient was experiencing, and gambling disorder is frequently missed in emergency settings where triage staff are trained to look for imminent physical risk. The study cannot separate sports betting from casino or slots play, though the market expansion it measures was overwhelmingly online. It cannot distinguish between more people developing gambling problems and the same number of people deteriorating faster — a meaningful difference for prevention policy. And Ontario is not the United States: its government-run platform predates the expansion, its advertising rules differ, and its single-payer data infrastructure is more complete than anything assembled across fifty state health systems.

Even so, the most transferable finding is about targeting. The increase did not diffuse evenly. It pooled in men under 45, and most heavily in men under 30 — the demographic that live-odds advertising, same-game parlays and in-app deposit bonuses are engineered to reach.

A Warning Written in Ontario, Mailed to the United States

Since the Supreme Court struck down the federal ban on sports betting in 2018, more than three dozen states have legalized it, and the vast majority permit wagering from a phone. Tax revenue has been the dominant argument in statehouses; treatment infrastructure has been an afterthought. Illinois became the first state to formally classify gambling disorder as an addiction under its substance use disorder statute only in July 2026 — and the accompanying fiscal analysis noted that less than a tenth of a percent of the state's gambling revenue was reaching treatment.

Myran's conclusion reads less like a research finding than a regulatory memo. Jurisdictions weighing an expanded online market "should carefully weigh these potential risks and, if proceeding, consider additional safeguards, including restrictions on marketing and higher-risk forms of gambling, alongside better recognition and treatment of gambling-related harms."

What Better Treatment Would Actually Look Like

The last clause is the one that costs money. Restrictions on advertising are cheap to write. Building a system that can absorb a 154 percent increase in severe presentations is not — and unlike opioid use disorder, there is no medication waiting on the shelf. No drug is approved for gambling disorder anywhere.

Care for gambling addiction therefore runs on therapy and structure: cognitive behavioral approaches that restructure the distorted beliefs driving chase behavior, motivational work for people who are not yet ready to stop, and the debt counseling, family involvement and peer programs — Gamblers Anonymous among them — that address the damage the betting apps never see. Screening is the missing entry point in most of the country. Brief validated questionnaires can be folded into primary care, emergency triage and behavioral health intake at almost no cost, and the Ontario data suggest the people who need them most are precisely the ones least likely to bring gambling up on their own.

The province did not plan to become the continent's test case. It simply moved first and kept records. Whichever state expands next will find out the same thing, and the emergency departments will know before the legislature does.