Risky behaviours like fighting and drinking are on the decline, and marijuana use among Canadian youth is now at its lowest level in 20 years, according to a new study on youth health.

The findings come from the 2014 Health Behaviour in School-Aged Children survey, a cross-national research study that gives a comprehensive snapshot every four years of the state of health for young people.

The survey sampled 29,784 students in Grades 6 through 10 from 377 Canadian schools across all provinces and territories, and was done collaboratively with the World Health Organization and the Public Health Agency of Canada.

Queen’s University researcher William Pickett says it’s overall a “positive message.”

“We’re seeing, nationally and internationally, a lot of different risk taking behaviours going down in young people,” he said.

The study says cannabis use in youth peaked in 2002 – where half of boys surveyed reported trying pot – and has declined ever since. It’s now at its lowest reported use among youth since the study has been conducted. Only 23 per cent of Grade 9-10 boys and girls in 2014 reported ever having tried cannabis, compared to 40 per cent and 37 per cent respectively in 2010.

“It’s a really interesting phenomenon. It goes beyond cannabis use – it applies to some of the high-risk drinking behaviours, fighting and physical violence. There seems to be a trend of things getting better.”

It’s not entirely clear why that’s happening but it’s a “provocative trend,” Pickett added.

The study showed a continuing decline of cigarette smoking among young people in Canada, declines in the rates of beer-drinking, drunkenness, and a “very low prevalence of use of other illicit drugs such as ecstasy, cocaine, and heroin.”

Reports of bullying have declined by half since the last survey, but reports of being victimized have remained the same. The emergence of e-cigarettes as a new phenomenon, meanwhile, is concerning to the researchers, with 26 per cent of boys and 21 per cent of girls in Grade 10 reported having ever used them. Also, obesity and physical activity rates were concerning. Only 1 in 5 reported participating in enough physical activity to meet Canada’s physical activity guidelines, and 1 in 3 boys and 1 in 4 girls were considered overweight based on their Body Mass Index.

There was one broad but key finding of the report that explains some of the “why” behind health trends: relationships matter a lot for health of young people.

“It didn’t matter what aspect of health you’re looking at – young people who had solid relationships with families and in their communities and schools, they tended to thrive,” Picket said.

He said that means that policy makers should “not just to focus on the health behaviour or the health outcomes we’re seeing but focus on the underlying determinants of health.”

Pickett pointed to efforts like the Promoting Relationships and Eliminating Violence Network (PREVNet), an anti-bullying organization made up of researchers and youth organizations that works at a community level, as an example of those kinds of projects that can have important effects.

“We do a lot of stuff to make our neighbourhoods great…to make our schools good social environments. But you can have the greatest external environment in the world but if you don’t have safety, you don’t have good communication at home and a child feeling safe at home they’re not going to thrive.”