It is a fact, sadly, that addiction will touch almost everyone’s lives, even the most accomplished among us. This is what happened to Nic Sheff, a top-of-his-class teen who started experimenting with pot before moving into harder drugs, gradually spiraling into a harrowing cycle of highs, lows, homelessness, sobriety and relapse. His father, Rolling Stone writer David Sheff, could only watch helplessly as Nic’s roller-coaster ride became worse