When it comes to teen substance abuse, it seems like we’re always playing catch up. Anytime a new drug hits the streets, its popularity soars, and we find ourselves fighting against it. At the same time, drugs that have been around for years sometimes rise sharply and unexpectedly in popularity. Why is that? There seems to be no rhyme or reason to either the increase, or decrease, in drug use among teens. Though certain trends have been discovered over the years, the cause of those trends seems a mystery.