"I did not have a problem," Johnson told Sports Illustrated. "It's just something I'm not going to get into. I have issues. But that's not the issue."
At the time of his announcement, Golf.com reported that Johnson had been suspended for six months after testing positive for cocaine, his third failed drug test since 2009. The PGA Tour denied his suspension to the Associated Press.
Johnson told the magazine he did not go to rehab, but that he did hire a life coach and a team of other experts.
"My way of getting rid of it was drinking or partying," said Johnson of how he dealt with stress. "Yeah, that might work for that day or the next week, but eventually everything keeps piling up.
"I don't miss waking up with a hangover, and I didn't drink very often. It was just when I did, it was a little too much."
The golfer had said previously he would not return to the sport until after his fiancee, Paulina Gretzky, gave birth to their first child. Johnson on Tuesday announced the birth of their son.
Johnson has not announced when he'll play his first tournament of the 2015 season. He played in 17 tournaments last season.
The Associated Press contributed to this report
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