Josh Peck Opens Up About His Past Addiction to Drugs and Alcohol: 'I Used It to Numb My Feelings'

He's been acting for over two decades, but Josh Peck, who first rose to fame on the hit Nickelodeon series Drake & Josh, doesn't revisit his past work.

"I don't even watch my new stuff," Peck, 35, tells PEOPLE in this week's issue. The actor, who currently has a recurring role on How I Met Your Father, adds: "I don't watch anything!"

Understandably because for Peck, Hollywood life was often the setting for some very painful times in his life, including a public weight struggle and a years-long drug addiction that he details for the first time in his new memoir, Happy People Are Annoying.

"I was always looking for something outside to fix my insides," says Peck, who has been sober since 2008. "But eventually I realized that whether my life was beyond my wildest dreams or a total mess, it didn't change the temperature of what was going on in my mind. I knew that nothing in the outside world would make me feel whole."

Born and raised in New York City, Peck began performing stand-up comedy as an adolescent before a breakout role on Nickelodeon's The Amanda Show led to Drake & Josh.

"I spent most of my life dying to be typical but I grew up with a single mom, I was overweight and I was a musical theater kid who really had no social status," says Peck, who recalls being teased relentlessly because of his size. "Comedy was my natural defense mechanism."

Emma McIntyre/Getty

But eventually, the actor, who weighed nearly 300 pounds at 15, (he recalls regularly eating large pizzas on his own) knew he had to make some healthy changes and after 18 months of diet and exercise, he dropped 127 pounds. But still, he wasn't satisfied.

"It became clear that once I lost the weight that I was the same head in a new body," Peck says. "What is really clear is that I overdo things. And then I discovered drugs and alcohol. And that became my next chapter. I used food and drugs to numb my feelings."

Josh Peck/Instagram

Experimenting with alcohol and drugs like cocaine as a teen into his early 20s provided an outlet for his private pain — and for insecurities stemming from childhood. "It was really a buffet," says Peck.

"I had this illusion of becoming more confident and attractive when I was partaking," he says. "I was trying to quiet that voice that woke me up every morning and told me I wasn't enough."

But eventually, due to his addiction, Peck found himself with a reputation in Hollywood for being "unstable and erratic," he recalls. "I had worked so hard for this thing and I was getting very close to losing it."

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Nickelodeon Josh Peck and Drake Bell

Peck joined a treatment program and got sober; a critically acclaimed role in The Wackness and then success in then-nascent social media outlets, including Vine and Instagram, followed.

"By walking through discomfort and by doing my best to break down the false identity I had for myself, I was able to get to the place that I was always seeking," says Peck, who is married to film editor Paige O'Brien and a dad to their 3-year-old son Max. "I'm just trying to do good work that makes people happy."

He also has a newfound appreciation for the journey that brought him here.

"It took me a really long time to love the 15-year-old version of me," says Peck. "But now I understand how strong he was. And I feel like everything in my life set me up to find this chapter of health, peace and contentment."

Happy People Are Annoying will be available on March 15.