The number of Ontario teens visiting a hospital emergency department for self-harm more than doubled over nearly a decade, according to a new study that researchers say shows rising demand for mental health supports in the province.

The study, published this week in the Canadian Journal of Psychiatry, also found the rates of visits by teens aged 13 to 17 for mental health problems rose 78 per cent in that same period between 2009 and 2017.

Increases in both types of visits were even more pronounced among teenage girls, it says.

The study was conducted using data on emergency department visits from the Canadian Institute for Health Information. It notes that teens who intentionally hurt themselves through poisoning or injury are at risk for repeated self-harm or suicide.

The authors say more research is needed to shed light on the reasons for these increases, which could indicate that more teens are harming themselves, more are seeking help in emergency departments, or a combination of both.

“Something changed in 2009,” said the study's lead author, Dr. William Gardner, a senior scientist at the CHEO Research Institute and professor of epidemiology at the University of Ottawa.

Before then, rates of emergency department visits by teens for self-harm had been declining, falling by roughly a third over the six previous years, and visits for mental health issues had increased only slightly, he said.

Though the study did not examine the possible reasons for the shift, Gardner said the research team has identified factors that warrant further examination.

One possibility is that the recession of 2008 contributed to familial stress, but Gardner said they would then expect to see the visit rates decline again as the economy improved.

Another potential factor is the launch of the iPhone in 2007, and the ensuing rise in smartphone use, he said.

“Engagement with social media could lead to increased rates of self-harm, at least for vulnerable adolescents,” Gardner said.

“This could happen in several ways: by normalizing self-harm, by triggering it, by getting teens to emulate self-harming peers, or by exposing youths to cyber-bullying.”

However, he said, social media may also benefit some struggling teens by providing them with a way to “escape social isolation or find encouragement to seek treatment.”

It could also be that efforts to destigmatize mental illness in the period studied have encouraged teens and their families to seek help when they need it, Gardner said.

“We have to say that if kids who are in trouble are more likely to come to seek care, that's good. It's sad that there's all those kids (who are struggling) but better to know about it than not,” he said.

However, emergency departments only provide crisis care and cannot offer the long-term support teens dealing with mental health problems need, Gardner said.

When the rate of teens going to the emergency department doubles, that means there is a great increase in demand for mental health care, and the number of providers has not grown in the same way, he said.

“It has a huge effect on waiting lists and on the case loads of providers,” he said. “We don't have the resources to cope with the demand and it's really important that people look at that.”