The 30-year-old is currently on a voluntary leave of absence from the PGA Tour after declaring in July he was taking time out of the game to confront personal challenges, subsequently missing the Ryder Cup.
Murmurings of a drug problem have consistently dogged Johnson, perpetuated by claims he has been serving a six-month ban after testing positive for cocaine, something he strenuously denies.
“I did not have a [cocaine] problem,” said Johnson. “It’s just something I’m not going to get into. I have issues but that’s not the issue. Like everyone I’m tested regularly by the Tour and as far as that’s concerned I haven’t failed anything.
“I would drink and drink to excess. The change I made is I just don’t do that any more. I definitely have given up hard liquor because that was the thing I went to, it’s been a big change.
“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. My way of getting rid of it [stress] was drinking or partying. That might work for that day or the next week but eventually everything keeps piling up.”
Johnson, an eight-time winner on the PGA Tour, is set to return to action at next month’s Farmers Insurance Open at Torrey Pines.