In the adolescent substance treatment program I run, 95 percent of the referrals are for marijuana, and in 2009 the number of referrals tripled. My young patients started telling me, "Doc, why would I stop using marijuana? It's medicine for my anger." I even heard parents say, "Maybe I should get my kid a medical marijuana card so they don't get in trouble for smoking pot."
Meanwhile, new research was showing that marijuana was potentially more damaging to the developing adolescent brain than we previously thought. There are studies that show adolescents who use marijuana regularly may have an increased risk of developing psychosis and may lower their IQ by up to 8 points. Some people laugh at me when I explain these research findings. "That's just reefer madness," they say. But for families grappling with drug-using children, this is no laughing matter.
I decided there was an urgent need to get out the word that marijuana is definitely NOT safe for adolescents. So over the next 3 years, I gave more than 100 talks to any group that would listen – Boy Scouts, churches, colleges, news organizations, parent groups, policy makers, professional organizations, Rotary clubs, schools, students, prevention experts, and teachers, to name a few. I also developed written materials for the Colorado Department of Education and my personal website to provide up-to-date information.
At heart, I am a scientist and a physician, not a public speaker. However, in 2009 only a handful of people were speaking up to protect kids from bad information about marijuana. I figured someone had to do so, and I'm glad I did.
Today, I see signs of hope. Parents frequently say to me, "Doc, I'm worried about what marijuana is doing to my kid's developing brain." They are getting the message, and I believe more and more kids are starting to understand as well.
 Hall W, Degenhardt L., Adverse health effects of non-medical cannabis use, Lancet, 2009 Oct 17;374(9698):1383-91. doi: 10.1016/S0140-6736(09)61037-0.