The former High School Musical pin-up hasn't spoken about the problems that prompted him to seek treatment last year, but now he tells The Hollywood Reporter he has learned major life lessons after hitting a low in his life.
He tells the publication, "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."
He adds, "When you have success young, and you accept the good things, you have to accept all of it. 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."
The actor admits that work was largely to blame for his past problems, because his career kept him away from family and friends.
He explains, "(It) started to become the reason to go anywhere, the reason to talk to anybody. The phone calls I received were regarding (work), the ones I wanted to make were regarding scripts or to producers. Slowly but surely, I was no longer living in my house. It was just hotel to hotel. So my hobbies went out the window."
He turned to drugs and alcohol in a bid to cope with his busy life, adding, "I was just so deep into my work, it was really the only thing I had. I clung to it in a way that became a little bit destructive."
Following his rehab stint, Efron moved into a new home with his brother, and he admits he's glad his former bachelor pad in Laurel Canyon is no longer his base: "That house was sort of in the middle of everything. It spit you out on one end on Sunset and on the other end onto Ventura Boulevard. It was a great idea initially - concrete floors, metal windows - a great bachelor pad, in my opinion. But it was surrounded by windows, and at night people started coming up and tapping on the glass while I was asleep. It started to get a little bit strange."
Meanwhile, Efron, who entered rehab for an addiction to alcohol and drugs a year ago, maintains a street fight he had with a homeless man in Los Angeles' notorious Skid Row district in March had nothing to do with his substance abuse issues, despite reports to the contrary.
He says, "I had a friend come pick me up late at night - we were looking for a place Downtown to get a bite and catch up. We were having trouble finding somewhere - a lot of places were closed - and the car ran out of gas off the 110 (freeway). It was ridiculous. We had to pull over.
"A homeless guy, or vagrant, tapped on the driver's-side window. Before I knew it, he (the friend) was out of the car, and they started fighting. I saw that (the homeless man) was carrying some sort of a knife, or shank, and I got out of the car to disarm him. At some point, he dropped the knife, and I got hit pretty hard in the face - and almost instantly the police were there to break up the fight.
"(It was) the most terrifying moment in my life."