Johnson - an eight-time winner on the PGA tour - withdrew from the WGC-Bridgestone Invitational in Ohio on Monday, citing personal reasons.
And the 30-year-old released a statement on Thursday underlining his intention to take a break, ruling him out of next week's PGA Championship and the Ryder Cup in September.
"I am taking a leave of absence from professional golf, effective immediately," the statement read.
"I will use this time to seek professional help for personal challenges I have faced.
"By committing the time and resources necessary to improve my mental health, physical well-being and emotional foundation, I am confident that I will be better equipped to fulfil my potential and become a consistent champion.
"I respectfully ask my fans, well-wishers and the media for privacy as I embark upon this mission of self-improvement."
PGA of America president Ted Bishop wished Johnson all the best and said he was sad the talented golfer will not be participating in Kentucky as well as Scotland, with the United States aiming to reclaim the Ryder Cup crown.
"Obviously we are disappointed Dustin Johnson will not be playing in the PGA Championship or be a part of the 2014 Ryder Cup squad at Gleneagles," said Bishop.
"Having spent time with Dustin at the last two Ryder Cups, we know he's an amazingly talented young man capable of winning major championships and becoming a Ryder Cup staple for the next two decades.
"We wish Dustin the best and look forward to his return."
Johnson has enjoyed a successful season on tour, winning the WGC-HSBC Champions.
He also finished second at back-to-back tournaments at the Pebble Beach National Pro-Am and the Northern Trust Open in February, while he was fourth at both the WGC-Cadillac Championship and the US Open.