The former Saturday Night Live regular is sharing details about his personal life and abusive childhood in the book God, If You're Not Up There, I'm F**ked.
In an excerpt, obtained by the New York Post, he writes, ""I kept a pint of Remy (Martin cognac) in my desk at work. The drinking calmed my nerves and quieted the disturbing images that sprang into my head... when drinking didn't work, I cut myself.""
And in 1998, Hammond confesses he was in such bad shape, he was admitted to the New York Hospital after being removed from the NBC TV studios in a straitjacket.
But his addictions only grew worse in 2002.
He continues, ""I'd started adding an obscene amount of cocaine to my binges... I had to be creative about how I did it without other people catching or letting it interfere with the work. At least too much.""
Hammond entered rehab in a bid to get clean but in 2009 he relapsed after stumbling upon the ""brilliant idea"" to try crack. He later spent time in a New York City crack house before finally finding a path to sobriety.
The tome is set to hit U.S. stores on 8 November (11).