Former evangelical leader Ted Haggard's drug and sex scandal made national headlines. How has his life changed since his first interview on The Oprah Show?

Read a book excerpt from Tweak: Growing Up on Methamphetamines by Nic Sheff.

Today, Fergie is a multiplatinum recording artist, who has traveled the world with the Black Eyed Peas. But in 2001, she was broke, unemployed and addicted to crystal meth. Fergie reveals why she turned to drugs after her girl group, Wild Orchid, was dropped from their record label. Watch as she shares her rock-bottom moment.

Beautiful Boy author David Sheff, his son Nic, and former drug addicts give insight into their addiction. What do they want parents and siblings to know about prevention and what caused their disease?

In her new book, Gayle Haggard talks about making the decision to stay in her marriage.