Celtic striker Leigh Griffiths says it is "laughable" to suggest he is on leave because of problems with gambling or drugs.

The Scotland international was last month given time off by the Scottish Premiership champions to deal with issues outside of football.

Griffiths, 28, insists his absence is down to mental health.

"I just want to settle one thing and to make it clear once and for all. I am off work due to my mental health state," he posted on Twitter.

"Not gambling, not drugs, or any other issue that has been written about me since December.

"The stories, the tweets, the lies that come out people's mouth is laughable, but I suppose if they're talking about me, they are leaving someone else alone."

Celtic boss Brendan Rodgers revealed in December that Griffiths would be unavailable for "a little period of time" as he "seeks professional help".

Griffiths last played for the Hoops against Kilmarnock on December 8.

"If anyone would like to come forward with real evidence that suggests I'm off with the above mentioned either from my employers or anyone else let's see it," added Griffiths.

"I'm putting this out there now because family and friends are being asked questions and they've been told to say nothing.

"But I'll not be silenced, especially by newspapers and idiots who can write tweets and make up stories and it grows arms and legs due to people's sad and pathetic lives."