Nic Sheff talks about his regrets.

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The first time Nic read his father's book, he says the painful consequences of his actions began to sink in. "I cried a lot," he says. "I didn't really realize that when I was using and when I was trying to kill myself through using that I was really affecting everyone around me. ... When I read his book and just saw how much his life had been ripped apart by my using and how his marriage had been tested and how my little brother and sister were affected, it was devastating."

Nic admits that although he wasn't thinking clearly during his addiction, he wasn't completely blind to the burden he put on his family. "There was a little piece of me deep down that knew what I was doing was really tearing my family apart, but I didn't want to see that," he says. "I think that's part of the reason that I kept using drugs—to blot out that pain."

Nic says he realizes he started abusing drugs to avoid seeing his true self. "I felt like if I looked inside of myself, I would see that I was just this ugly, disgusting, worthless person. I was so scared of that, I started drinking and using so that I could escape," he says. "It's so stupid. I don't know what I was running from that whole time."