Pretty sure the up-tick has more to do with socioeconomics and the drug war than anything else.

I don't have any sources at hand, so take this with a grain of salt. But, I've often seen it argued that Reagan era drug policies were detrimental to poor minorities, especially black men. The problems we see today are the trickle-down effects (couldn't resist) of turning an entire generation of fathers into disenfranchised criminals.