Originally published in the Toronto Sun

A new study that analyzed adolescent emergency room visits could cause the idea pot legalization is safe for youth to go up in smoke.

Researchers studied the critical care records of kids between the ages of 13 and 21 at Children’s Hospital Colorado over a 10-year period and found ER visits related to pot use are on the rise.

According to a study presented by Dr. George Sam Wang, an assistant professor of pediatrics at the University of Colorado, there were 639 pot-related visits to the hospital in 2014 – more than four-times the 146 similar visits in 2005. In total, researchers found there were 3,443 marijuana-related visits during the period in which the data was collected.

Mental illness symptoms related to marijuana use made up the vast majority (66%) of those hospital visits.

Colorado has been at the forefront of marijuana legalization in North America, having enacted pot use for medicinal purposes in 2010 and recreational purposes in 2014.

“The state-level effect of marijuana legalization on adolescent use has only begun to be evaluated,” Dr. Wang said, according to the American Academy of Pediatrics. “As our results suggest, targeted marijuana education and prevention strategies are necessary to reduce the significant public health impact the drug can have on adolescent populations, particularly on mental health.”

Following the Trudeau Liberals’ introduction of the proposed Cannabis Act C-45 in the House of Commons last month, some Canadian health care professionals, such as the Canadian Psychiatric Association, have expressed concern that any legalization of marijuana in Canada “must protect mental health of young Canadians.”