The World Health Organization and the Public Health Agency of Canada have released the results of the latest survey of nearly 30,000 children in 377 schools across Canada, first administered in 1990.

The 2014 Health Behaviour in School-aged Children survey is conducted in 44 countries every four years to take a snapshot of the mental and physical health of children aged 11 to 15 in Grades 6 through 10.

“This study is about life, the universe and everything for teenagers,” said Canadian co-author Elizabeth Saewyc, a professor at the University of British Columbia. “We look at everything from whether they are eating their vegetables to getting enough sleep and risk-taking behaviour.”

Pot use down

Cannabis use is now at its lowest level since 1990. About 23 per cent of boys and girls aged 15 and 16 report having tried the drug, which is down by half from its peaks in 2002, when 50 per cent of boys said they had smoked, and 1998, when 40 per cent of girls had tried pot.

“Young people that have positive relationships with adults and that feel connected at school are far less likely to use cannabis or participate in risky drinking,” said Saewyc.

A dramatic drop since 2010 helped erase the steady growth in experimentation with cannabis recorded through the ’90s.

Older teens exercise less

Only one in five children in the survey participates in moderate to vigorous physical activity often enough to meet Canada’s physical activity guidelines. That number hasn’t changed much since 2002. Time spent on physical activity declines with age until Grade 10, when 22 per cent of boys were active for at least 60 minutes a day and only 10 per cent of girls. More than 50 per cent of boys and 40 per cent of girls watch more than two hours a day of television and nearly as many spent more than two hours a day playing video games.

Teen girls sexually harassed

One in four children reported being bullied at least twice a week in 2014, a figure that has been rising since 2006. However, the number of children that admit to victimizing others has dropped by half over the same period. About two-thirds of girls at all ages report being indirectly bullied, often through exclusion or spreading lies, and by Grade 10, 40 per cent say they have been sexually harassed. Nearly 30 per cent of boys report being physically bullied, about double the rate for girls.

Signs of depression

When researchers probed for early signs of depression — feeling sad or hopeless every day for two weeks in a row — they found Grade 9 and 10 girls were most at risk. More than 40 per cent reported sadness that prevented them from doing their usual activities. One in three Grade 9 and 10 girls reported that they often felt lonely.

“The differences start as early as Grade 6, but by Grade 10 the indicators are twice as high for girls than boys,” said Saewyc.

Sugar waning, but ...