We all knew Crochet can help people. The concentration required to crochet helps people focus and when they focus, their mind is taken away from other matters.
And if you learn to crochet, you can create something. Not just for yourself, but for others in need.
The Blanket Project (report) does this by going into prisons (normally juvenile) and helps some of the troubled kids to learn to crochet blankets for the needy.
crochetconcupiscence has put together a list of 5 other prisons that do the same thing. Read the list of these prisons here: Crochet in Prisons.