Many people would expect that the legalization of medical marijuana in 2010 followed by the legalization of recreational marijuana in 2014 would increase the rate of adolescent marijuana use in Colorado.

National and state data from 2015, however, revealed that admitted use of marijuana remained about the same for adolescents over the last decade. In spite of that surprising finding, Dr. Sam Wang, assistant professor of pediatrics and emergency medicine for Children’s Hospital Colorado (Children’s Colorado) located at the University of Colorado Anschutz Medical Campus, and his colleagues at Children’s Colorado noticed an anecdotal uptick in visits by adolescents for marijuana-related issues to Children’s Colorado emergency rooms.

“We anecdotally noticed that we were seeing a lot more kids testing positive for marijuana and saying that they used marijuana,” Wang said.

To determine whether the rate of visits to the emergency room for marijuana-related issues was increasing, Wang and his colleagues reviewed marijuana-related diagnostic codes and positive urine drug screens for adolescents, ages 13 to 21, in the Children’s Colorado EDs and urgent care clinics from 2005 to 2015.

Their study, “Impact of Marijuana Legalization in Colorado on Adolescent Emergency and Urgent Care Visits,” was published in the Journal of Adolescent Health in August 2018.

The data confirmed their observations of an increase in marijuana-related ED visits. What they did not expect was the magnitude of the increase. Annual marijuana-related visits jumped from 161 in 2005 to 777 in 2015. The data from the year 2015 reflects just one year of legalized recreational use and five years of legalized medical-only use.

The ED visits included patients who came in complaining of acute effects of marijuana, including psychosis, agitation and hallucinations. It also included patients who came in for other issues and admitted to marijuana use during their visit or tested positive for marijuana through a urine drug screen.

Dr. Rakesh Mistry, director of research for the Children’s Colorado Section of Emergency Medicine and associate professor of pediatrics at the CU School of Medicine, who was part of the research team, said that many of those who visited the ED for marijuana-related issues are already a population that’s at high risk for substance abuse.

Behavioral health evaluations were the main reason for many of these ED and urgent care visits, accounting for 67 percent. Researchers noted that annual behavioral health evaluations in patients with either admitted marijuana use or positive drug screens also had a dramatic increase, from 84 to 500 for the same time period. In total, 71 percent of those with diagnostic codes related to marijuana or a positive urine drug screen were also diagnosed with mental illness.

The most common diagnoses were depression, mood disorder, and anxiety. Researchers also noted that a large portion of those who tested positive for marijuana also tested positive for other substances such as alcohol, amphetamines, and opiates. Some other co-diagnosis with marijuana use were respiratory, neurological, gastrointestinal, and poisoning or overdose.

“A lot of patients came in for psychiatric complaints or depression … that population is already going to undertake risky behaviors like substance abuse. This study helps us identify a particular population that is at increased risk for safety events, for suicide and other injuries. We want to find a way to help that population,” Mistry said.

As Colorado and other states continue to evaluate how legalization of marijuana affects its population and especially adolescent health, this research illustrates that while the number of adolescents admitting to using marijuana may not have changed much with legalization – perhaps the way they are using it is.

“There was a recent paper that showed that adolescents are using more vaporizers and edible products for marijuana and that’s concerning. Those products have more concentrated, higher potency THC [the ingredient in marijuana that makes you feel high]. So, while we may not be seeing overall usage changing, the quality/quantity of use is changing, and that may in and of itself impact adolescent health,” Wang said.

Based on their findings, Wang and Mistry say that the effects of legalized recreational marijuana on behavioral health need to be explored more. Mistry said he believes there should be more education and regulation to accompany the legalization of marijuana, which is illegal for use in people under age 21.

“Although legal for adult use in many places, it’s still not appropriate for adolescent use. It can impact their future cognitive abilities and academic achievements, especially the higher potency products that are now literally available everywhere,” Wang said.

To prevent teenagers from using and abusing marijuana, or cigarettes, e-cigarettes, alcohol or any illicit drug, it’s important to talk to your children about the dangers of using at a young age, and to keep the dialogue open and ongoing, doctors say. Click here for more information about “How to talk to your kids about marijuana.”