Shia LaBeouf says drinking "almost" messed his life up.
The 'Transformers' star insists he is keeping his "head low" and has been sober for a year.
He said: "That s**t almost f***ed up my life. Alcohol or any of that s**t will send you haywire. I can't f**k with none of it. I've got to keep my head low.
"I got a Napoleonic complex. I start drinking and I feel smaller than I am, and I get louder than I should. It's just not for me, dude.
"I had people tell me it was going to [ruin my career]. People I respected - dudes I wanted to work with - just looked me in the eyes and said, 'Life's too short for this s**t.' I'm still earning my way back. I'm happy working."
And whilst the 30-year-old actor grew up amongst fellow Disney alumni like Hilary Duff and the Jonas Brothers, he never felt like he fitted in with them.
Speaking about his father's friends, he added: "There were drugs everywhere - marijuana, cocaine, heroin. [My dad] gave me my first joint when I was probably 11 or 12.
"They would invite the Hilary Duffs and Miley Cyruses to go to the Jonas Brothers concert, and I'd be there with my friends. But we were outsiders. It felt distant."
However, Shia believes he would not have got some of the work he has without being a bit of a "loose cannon".
He told Variety.com: "I don't think I'd be working with the directors I've been working with if I had not f***ed up a bit. They wanted a f***ing fireball. They wanted a loose cannon. I'm learning how to distill my 'crazy' into something manageable, that I can shape and deliver on the day ... [Before] I was an open wound bleeding on everything."
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