Ontario’s Big City Mayors are calling for the province to address a worsening homelessness crisis.
On Aug. 16, the mayors of 29 Ontario cities called on the government to create a dedicated mental health and addictions ministry and the legal tools to mandate treatment.
“The homelessness, mental health and addictions crisis is getting worse in communities across the province, and the status quo is not an option,” Marianne Meed Ward, chair of the advocacy association and mayor of Burlington, said in a group statement.
But experts say mental illness and addiction are only part of the picture.
Poverty and a lack of affordable housing can push vulnerable people into homelessness, while homelessness itself can worsen mental health and substance use.
“The bottom line is that substance use disorders and mental illness are highly linked to homelessness,” said Dr. Stephen Hwang, a physician at a research centre focused on homelessness, housing and health within St. Michael’s Hospital in Toronto.
“But they’re not fundamentally what’s driving the increase in homelessness we see in our communities.”
Growing homelessness crisis
Almost 85,000 Ontarians are known to have experienced homelessness in 2025, according to a January update by the Association of Municipalities Ontario.
This represents about 0.5 per cent of Ontario’s population, and is up eight per cent from 2024 and nearly 50 per cent from 2021.
Ontario’s Big City Mayors say the worsening and increasingly visible crisis is straining municipal resources and affecting public spaces.
“[T]he property tax base cannot continue to carry the growing costs of healthcare, housing and social supports,” the group said in its statement.
The group is calling for the province to create a dedicated mental health and addictions ministry, expand access to recovery and treatment programs, and review Ontario’s Mental Health Act and Health Care Consent Act to mandate treatment.
Data show that mental health and substance use problems are highly prevalent among people experiencing homelessness.
In a 2024 survey of people experiencing homelessness, nearly 60 per cent reported a mental health issue, and a similar proportion reported substance use disorders. Almost half reported both.
“[P]eople with mental illness and people who have substance use disorders are more likely to become homeless,” said Hwang. “That’s why the prevalence of mental illness and addictions in the homeless population is … much higher than in the general population.”
But the relationship runs in both directions. Homelessness itself can worsen mental health, says Tim Aubry, professor emeritus at the University of Ottawa.
“Staying in shelters is, for a lot of people, very traumatic because of the conditions,” he said. People can be exposed to conflict and victimization in shelters, while those sleeping outdoors face their own dangers.
Mental illness alone, however, does not explain the rise in homelessness. Poverty and a lack of affordable housing are fundamental drivers, says Hwang.
On average, Canadians now spend between 35 to 50 per cent of their income on housing, exceeding the Canada Mortgage and Housing Corporation’s affordability benchmark of 30 per cent. As Canadian Affairs recently reported, a dearth of new housing supply has exacerbated the housing crisis.
Hwang likens the housing crisis to a game of musical chairs. When housing is scarce, vulnerability shapes who ends up on the street, he says.
“There is a reason that certain kids are more likely to lose the game of musical chairs,” he said. “Maybe it’s because they’re smaller, or because they have a disability, or some other reason that they can’t get to the chair in time.”
What follows is a “vicious cycle,” says Hwang. People who are unwell can become homeless, then homelessness makes them more unwell, worsening mental illness and substance use.
“Substance use is a coping mechanism for people who are homeless, so if they were [even casual] substance users … it’s just going to get worse,” said Aubry, who is also outgoing co‑chair of the Canadian Housing First Network, a research and advocacy network.
Hwang says the increased visibility of drug use in encampments does not necessarily reflect a sudden rise in addiction.
As more people become homeless, drug use that once happened behind closed doors can become visible.
“Housing shortages and the affordability crisis is exposing people who might have had a substance use disorder who were perhaps functional because they were housed,” he said.
Breaking the cycle
For people already experiencing homelessness, stable housing is the foundation for recovery.
Hwang was previously a researcher with At Home/Chez Soi, a landmark project in five Canadian cities that took a “housing first” approach to homelessness. Participants were permanently housed before having to address addiction or mental illness issues.
A housing first approach is one of the strongest evidence-based approaches for people with complex mental health and substance use challenges, says Aubry.
Aubry’s own research, including a 1,200-person study in Ottawa, Toronto and Vancouver, found that subsidized housing and higher income were the strongest factors associated with exiting homelessness.
But Canada’s supply of non-market housing — such as social housing at below market rates — remains far below what experts say is needed.
Since 2017, non-market housing completions have stagnated at roughly 4,000 to 6,000 units a year, while homelessness has risen 22 per cent, a 2025 report commissioned by the Federal Housing Advocate found. The advocate has called on Ottawa to build 200,000 non-market homes annually.
But housing alone is not enough, says Hwang. People also need accessible mental health and addiction care.
“It’s absolutely essential that we link mental health treatment to housing … forced treatment for mental illness or addictions is not the answer,” said Hwang.
“We have no evidence — there’s no research — to suggest that forced treatment is effective, and we don’t have the capacity in the system to provide service to people who voluntarily seek treatment.”
