Big hitting golfer Dustin Johnson is serving a six-month suspension from the PGA Tour after testing positive to cocaine according to Sports Illustrated in the USA.

Reporting on their website golf.com, the magazine says Johnson has now failed three drug tests, one for marijuana in 2009 and two for cocaine, in 2012 and 2014.

The magazine says Johnson was suspended for the 2012 failed test but that was kept quiet as the PGA Tour’s drug-testing policy does not require disclosure of suspensions or any disciplinary action against players who test positive for recreational drugs.

Johnson has simply said he is taking a break from golf due to “personal challenges”.

“I am taking a leave of absence from professional golf, effective immediately. I will use this time to seek professional help for personal challenges I have faced,” Johnson said in a statement released on Thursday.

“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.”

Johnson, his agent and the PGA tour have so far refused to elaborate or make further comment.

Johnson is missing at an important time of the season with the year’s final major, the PGA Championship, on next week.

He will also miss the US PGA tour playoffs and will not take his place in the US Ryder Cup team to play in Scotland at the end of September nor the WGC Champions event he won in China late last year.