Surprised no mention of Edwin Rosario yet. Chapo was a drunk and a drug addict and died of an aneurysm because of his habits.
I seriously doubt Tyson was into any sort of drugs while he was with D'Amato and his first few years after Cus died. Yes, he would have dabbled a bit, being a kid in the slums, but not when he was training to be a boxer 24-7. I think Tyson exaggerated his experience with drugs as a youth in hindsight to explain the cocaine habit he had a lot later on, at age 40.
The answer to the question the thread is asking would be too long. I think people in general take recreational drugs and/or alcohol. Yes, professional athletes do too. Top boxers are possibly more prone to doing so than a lot of other athletes only because they have more 'off time' when they get to the top level. I'm guessing most people keep their drink and drug usage quite private/secret. At least in the past that would have been the case. Since the 1980s it's become fashionable for celebrities to 'confess' their drug habits, which is a pathetic spectacle, imo. Like we should give a f**k.
Kirkland Laing beat Roberto Duran... but couldn't beat the drink and drugs. Ray Leonard on the powder in the 80's.
Nobody mentioned Alexis Arguello, yet? That is a tragic story. Not sure if he was doing drugs and alcohol in his prime years, but once he retired vice caught with him quickly
Johnny Tapia did coke to the point of having multiple heart attacks throughout his career. Maybe the worst case, but he still had a good career.