The dangers of Mary Jane are greatest for those who inhale as teens
This article was originally published with the title "Mind In Pictures"
Dwayne Godwin is a neuroscientist at the Wake Forest University School of Medicine.
Jorge Cham draws the comic strip Piled Higher and Deeper at www.phdcomics.com. He is also co-author of the new book We Have No Idea: A Guide to the Unknown Universe, published by Riverhead Books.