The 26-year-old actor checked into rehab last year after his problems started to get out of control but he says he wouldn’t take anything back.
Speaking to a US magazine, Zac said: “I was drinking a lot, way too much. It’s never one specific thing. I mean, you’re in your 20s, single, going through life in Hollywood, you know?
“Everything is thrown at you. I wouldn’t take anything back; I needed to learn everything I did. But it was an interesting journey to say the least.”
Following rehab, the former High School Musical star now has sessions with a therapist and attends alcoholic anonymous meetings.
He said: “I just started going. And I think it’s changed my life. I’m much more comfortable in my own skin. Things are so much easier now.
“No matter who you are, you face challenges growing up. You go with your things, you learn, you have to. It’s impossible to lead an honest and fulfilling life as a man and not make mistakes and ‘fess up to them when you need to. But it’s especially humiliating when they happen to be so public and so scrutinised.”
Zac claims that the pressures of growing up in the spotlight, and feeling like he had to be a role model, played a part in his battle with drink and drugs.
“When you have success young, and you accept the good things, you have to accept all of it,” he said. “You have to accept the moments of glory but also a great responsibility.
“And that responsibility, to some degree, involves being a role model. At the same time, I’m a human being, and I’ve made a lot of mistakes. I’ve learned from each one.”