There are rumours of famous traders who drink heavily but I don't want slander anyone. This is a rare clip of a trader (Greg Riba), although he may have retired from trading at that point, actually go on the record while intoxicated: He does share some good trading wisdom: Queued to start around 34:30
I dated a girl who's previous boyfriend was nicknamed "The wolf of Old Street", or just one of them, a trader area in London, and he drank and took so much coke that in the four years they were together, since 28, he could not function without viagra and sometimes had to also inject it into his John Thomas. She said he was a top trader though.