TORONTO -- While provinces have been keeping track of their daily COVID-19 cases, another insidious crisis has been quietly becoming more and more deadly throughout the pandemic: opioid overdoses.

In May, 170 people in B.C. died from suspected overdoses, the highest number in a single month ever recorded in the province.

It’s the collision of two health crises.

For people with opioid addiction, it can be a struggle to obtain comprehensive care due to widespread stigma and lack of resources. Now, with COVID-19, that struggle has intensified. The pandemic forced many treatment centres’ programs to scale back operations, and in some cases, even close.

One B.C. clinic that has stayed open during the lockdown is the Commercial Health Centre.

In a Vancouver neighborhood full of tree-lined streets, it’s a place for addicts to turn to when they’re struggling.

Sixty-year-old Lori Vidler credits the centre with saving her life. Vidler has long struggled with opioid addiction.

“If I had not made the choice to come into the clinic, there is absolutely no question in my mind that I would be dead,” she told CTV News.

The Commercial Health Centre -- an outpatient rehab clinic -- helped the grandmother kick street drugs by prescribing methadone.

But when the pandemic hit, the clinic was uncertain at first if it would be able to stay open. Staffing shortages and physical distancing rules have made it hard for these centres to operate.

Dr. Carole Richford, the clinic's psychiatrist, knew closing would put people at risk of relapse or overdose.

“There was many frantic phone calls,” Richford told CTV News.

So the doors remained open.

“This has been an incredibly stressful time on people,” she said. “And we know that people need to know that there is help out there for them.”

COVID-19 has swept across Canada and claimed lives in every corner of the country. It has also brought with it a multitude of stresses.

For people who experience addiction and mental health concerns, that additional stress can pose a serious risk to health.

A new report released today by UBC researchers and the Canadian Mental Health Association found that 39 per cent of people in Canada say their mental health has declined due to COVID-19.

The study also found that COVID-19 has made things worse for those who are already vulnerable. People already struggling with their mental health were two times more likely to say their mental health declined due to COVID-19, or to report having had suicidal thoughts.

“COVID-19 may have been termed the ‘great equalizer,’ but it certainly hasn’t affected everyone equally -- people who were already experiencing mental health challenges and experiences of marginalization appear to be the hardest hit,” lead researcher Emily Jenkins, a professor of nursing at UBC, said in a press release.

This aligns with the impact that Richford and other workers at the Commercial Health Centre have seen.

Since April, calls to the clinic have doubled, and staff have seen a surge in demand for substance abuse treatment.

One patient, Bill Bingham, started using when he was 11 years old.

He's been clean for a decade, but says the isolation that came with COVID-19 threatened his sobriety.

“Being alone and being in my head a lot of times is not a good place,” Bingham told CTV News. He said it feels like if you’re “not caring and going and getting loaded, so what if you overdose?”

Last month, five British Columbians died every day. Most were alone when they overdosed.

It’s a statistic that breaks Vidler's heart.

“The addicts that have died during this pandemic, these are people’s mothers, fathers, children,” she said.

Since March, more than 400 people in B.C. have died of suspected overdoses.

That's more than double the lives lost to COVID-19 within the province.