Phil Mickelson says his gambling addiction "caused a lot of harm" to relationships with friends and family but that he is now in recovery.
The six-time major winner said his gambling had "crossed the line of moderation and into addiction".
He warned gamblers not to "confuse your enablers as friends like I did".
"It's like a hurricane is going on outside and I'm isolated in a shelter oblivious to what was happening," Mickelson, 53, wrote on social media.
"The money wasn't ever the issue since our financial security has never been threatened, but I was so distracted I wasn't able to be present with the ones I love and caused a lot of harm. This lack of presence has been so hurtful.
"'You're here but you're not with us', is something I've been told often throughout my addiction. It affected those I care about in ways I wasn't aware or could fully understand."
American Mickelson, who moved from the PGA Tour to the Saudi Arabia-backed LIV Golf last year, added that it was the "love, support and commitment" of his wife Amy that helped get him "back on track".
"She has loved me and supported me through my darkest and most difficult times. I couldn't have gotten through this without her," he said.
"After many years of receiving professional help, not gambling, and being in recovery from my addictions, I'm now able to sit still, be present in the moment and live each day with an inner calm and peace."
Mickelson, who has won 45 PGA Tour titles, has previously discussed his gambling and how he had taken steps to address it.
In August he denied claims by noted sports gambler Billy Walters that he had bet on the 2012 Ryder Cup, saying he would "never undermine the integrity of the game".
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