Who are some boxers whose career was derailed by alcohol or drugs?

[Marchegiano]

Ike Ibeabuchi

[Damn Wicked]

Oscar DeLahoya and Ricky Hatton.

Both those guys ruined the end portion of their fighting careers. Both guys partied hard and got fat between fights. You could see how faded they were in their final years.

[sbbigmike]

Errol spence...

And obviously geeked leading up to Crawford hope it's not a bad omen

[shawnkemp804]

Tony Tucker and Tony Tubbs

[ProblemChild_JakePaul]

One thing that always struck me as odd is how Dan Rafael is staunchly anti-alcohol, but is morbidly obese.
His stance almost has to be because of the psychological effects of alcohol and not the physical ones.

[MinuteMaid5]

Mike Tyson