Specific examples of Marijuana as a gateway drug?

I'm doing a paper on the effects and consequences of early marijuana use, and I want to use specific examples of heroin and coke addicts that started on Marijuana when they were 13/14/15. Do you know any specific examples? Or know of any place in which I can find specific examples?
Update: I need something more along the lines of;
Anne Doe started smoking Marijuana at age 13, she began to use it more and more chronically until 17, in which she moved onto harder drugs, more specifically, crystal meth.
6 answers 6