Manchester United legend Eric Cantona admits leaving the club was difficult.
The French star said he still finds it difficult going back to Old Trafford - because he found it so difficult to leave in the first place.
Cantona, 45, quit the club in May 1997 after five successful seasons, but admitted it was not an easy time in his life.
He told GQ: "If you are a heroin addict, and you've gone through the agonies of withdrawal, you don't go back and start hanging out with your dealer.
"I found leaving Manchester United very, very hard.
"It was, as I say, like quitting a class A drug. Psychiatrists have demonstrated that the body of a retired professional footballer can replicate the kind of symptoms that you get with abrupt opiate withdrawal.
"And that's why I've avoided going back."
