I've been following the progress of "Devil's Playground" for a few months now. It's a film about the Amish coming-of-age period called rumspringa, (see IHT/NYT article here) which means "running around". Basically, before young adults are baptized in the church, they run around with a freedom that they'll never enjoy again once they become baptized church members.
Predictably, a good number of them fall into at least moderate alcohol and drug use during this period, but an amazingly high percentage (I've seen estimates ranging from 75% to 95%) do eventually come back to their communities and become members of the church. Those few months or years before their return account for the stories you hear about Amish kids getting busted for dealing coke or driving their buggies while drunk.