Why wonder?
I thought such usage was already documented?
( JustHere, Fri 4 Apr 2003, 17:12, archived)

Wasn't it
'shrooms he was into?
(Active Hiatus, Fri 4 Apr 2003, 17:14, archived)

Whichever
hallicinogens were definitely involved! :-D
( JustHere, Fri 4 Apr 2003, 17:25, archived)

well,there is some truth
the "mad hatters" were actually real, in a sense.
in earlier times, hatmakers used materials that, over time, induced brain damage in a great many of them. thus, the term was coined.
(Rumours of Dinoadventures death have been greatly exaggerated., Fri 4 Apr 2003, 17:34, archived)