Health, law enforcement and school officials met Friday in Durango to grapple with the effects of legal marijuana on children and to push back on what they said were myths about marijuana use.

Dr. Christian Thurstone, the main presenter, repeatedly compared Colorado’s legal marijuana industry to Big Tobacco’s history of misleading the public and appealing to underage consumers.

Thurstone is an attending physician at Denver Health’s Adolescent Substance Abuse Treatment, Education and Prevention Program of Behavioral Health, and an associate professor of psychiatry at the University of Colorado Denver.

Thurstone objected to some findings in a state report released Thursday that found teen marijuana use actually declined from 2011 to 2013. During that time, the medical marijuana industry grew dramatically in Colorado.

“It’s irresponsible to make that conclusion – that marijuana commercialization, legalization, causes a drop in youth marijuana use,” Thurstone said.

Thurstone said the report uses 2013 data, before nonmedical retail marijuana sales began, and surveyed only children who attend school, not including dropouts. He also said the drop was not “statistically significant.”

The Community Cannabis Forum drew more than 100 professionals to Miller Middle School’s auditorium. The forum had the atmosphere of a combined D.A.R.E. class, school board meeting and professional convention. Thurstone made two presentations, followed by a panel discussion.

Thurstone recited a litany of marijuana research. He said marijuana use in adolescence is associated with decreased IQ, increased risk of later addiction and higher risk of psychosis, including schizophrenia, later in life.

The adolescent brain has well-developed pleasure centers but has an immature prefrontal cortex, which controls impulses, he said.

“They have a gas pedal that works great and a brake that’s not fully developed,” he said.

Thurstone said there is no longer any debate among scientists that marijuana can cause physical as well as psychological addition. The risk of addiction is about one in six for adolescent users and one in nine for adult users, he said.

Kristen Hale, clinical manager for Axis Health System in Durango, said chronic teenage users are smoking illegally obtained medical marijuana. Colorado law limits medical and retail marijuana to adults 21 or older, but teens are still getting it, she said.

“They’ll straight-up tell you what they’re smoking,” she said during the panel discussion. “They know what strain they’re smoking. They know what they like the best.”

Another problem has been teenagers who smoke with their parents, Hale said.

Scott Smith, a group facilitator with La Plata Youth Services, said parents who use marijuana can be an obstacle in treating their teenagers.

“If parents are continuing to use and tell their kids not to, it’s a huge mixed message,” Smith said.

Thurstone recommended one-on-one motivational interviewing as an effective treatment for addiction. Others said group counseling for adolescents had proved ineffective.

Jonny Radding, co-owner of Durango Organics and Wellness Center, was the only marijuana industry representative to attend.

He said his facility works to make sure everyone who enters the dispensary has a valid medical marijuana card. He also encouraged parents to educate their children about marijuana’s drawbacks.

cslothower@durangoherald.com