Most teens think pot is no biggie. And it probably isn't if they are using infrequently as a treat. But for many teens, pot is becoming the high of choice. It mellows you out, you don't throw up from it, and hey it's legal in Colorado so how bad can it be.
Well as it turns out, it's not good. In the developing brain of teens, it changes the way the brain grows. Rather than trotting out your own lecture on why drugs are bad, why not read this article at the dinner table!
http://www.bostonglobe.com/lifestyle/health-wellness/2014/04/15/casual-marijuana-use-creates-brain-changes-new-report-shows/X1cN8A7h5pOVJkeYkXTXlJ/story.html