Canadian hospitals saw a spike in the number of youth hospitalized for eating disorders during the COVID-19 pandemic, new data from the Canadian Institute for Health Research reveal.

The numbers released Thursday show girls aged 10 to 17 with eating disorders were hospitalized nearly 60 per cent more following the onset of the pandemic.

The rate for this cohort went from 52 hospitalizations per 100,000 people in 2019-20 to 82 hospitalizations per 100,000 in 2020-21.

It paints a stark portrait of one facet of youth mental health across the country, experts say, noting that an eating disorder needs to be extremely severe to require hospitalization.

"That's really the tip of the iceberg when it comes to young people with fairly significant eating disorders, because there are so many barriers to accessing care," said Dr. Leanna Isserlin, psychiatric director of the child and adolescent eating disorders program at CHEO.

"And so many young people would never meet the criteria for hospitalization but ... are still very unwell with their eating disorders."

The rate of eating disorder hospitalizations for youth of all genders aged five to 24 in Canada was 20 per 100,000 in 2020-21, up from 15 per 100,000 in the two years leading up to the onset of the pandemic.

The data was drawn from the Discharge Abstract Database and Ontario Mental Health Reporting System.

Isserlin said she's seen the spike bear out in her practice at the Ottawa-based children's hospital.

"We had to redistribute our staff. We had to pull staff from other parts of the mental health-care programs who typically would treat things like depression and anxiety or other psychiatric disorders, who came to help on in our unit," she said.

Tracy Johnson, director of health system analytics at CIHI, said it's hard to measure the overall prevalence of eating disorders, so looking at hospitalization data is a good jumping off point to measure trends.

"We do know that advocates suggest that we don't have enough resources for eating disorders, and that goes for everything from identifying kids as early as possible and getting them more appropriate care," Johnson said.

That said, there's also limitations to the data.

"We don't know who doesn't seek care for these things," Johnson said. "You get admitted to hospital because you're the sickest of the sick kids."

The boost in hospital visits and admissions for eating disorders was not, however, reflected for other mental health issues.

Hospitalizations for anxiety disorders decreased from 39 per 100,000 youth in 2019-2020 to 35 per 100,000 in 2020-2021, while for psychotic disorders the numbers held relatively steady, going from 69 per 100,000 to 70 per 100,000.

Emergency department visits for substance-related disorders, meanwhile, plummeted.

The rate in 2019-2020 was 385 per 100,000 youth, and in 2020-2021 it was 280 per 100,000.

"Overdosing on alcohol was down," Johnson said. "Kids were at home, there were no parties and gatherings, there wasn't university parties. So all of those things contribute to a decrease in both hospital visits and (emergency department) visits for substance use."

The numbers counter the narrative that the pandemic was bad for all aspects of mental health, Johnson said.

"The triggers for some things are different."

This report by The Canadian Press was first published May 5, 2022.