Tyson Fury took cocaine to deal with depression brought on by not getting the recognition he felt he deserved after becoming world heavyweight champion, his trainer said.
Fury tested positive for the drug earlier this month after twice postponing a scheduled rematch against Wladimir Klitschko.
In a subsequent interview with Rolling Stone the troubled boxer revealed his struggles with mental illness, telling the magazine if "I could take my own life, and I wasn't a Christian, I'd take it in a second."
Peter Fury, the 28-year-old's trainer and uncle, told BBC Radio 5 Live's Sportsweek that he didn't believe the British boxer was addicted to drugs.
He said: "Whatever he's taken will be a result of the depression. The way he's been received since he won the world title, to him, in his mind, he wasn't recognised in anywhere near the way he should have been.