Are "acid casualties" a bit of a myth? I mean how many people have taken acid once, or even many times - "many" as in ten or seventy, as opposed to doing it every weekend for decades, and been permanently damaged? Some, no doubt. I've met maybe two or three people who have taken it once or a handful of times, had one bad trip and will not take it again, so to some extent they are "damaged" but they seem generally fine and functional otherwise.
My guess would be those who are permanently adversely affected have a tendency towards psychosis already and it simply "brought out" what was already there, alcoholism or at least heavy drinking might do the same thing, as might trauma, grief or enough stress.
The Dielectric club in Leicester was so exclusive, they had their own record label, 'Die Hard' .. 9pm start, 7am finish every Saturday night .. dub plates dropped most nights, hardcore rave security so tight the plain clothes police gave up in the end, my car was nicked one morning from their car park, I got it back but all the windows had been smashed out. 20K sound system and a dance floor purposely built with industrial strength springs underneath, best nightclub I've ever been to by miles ..
The Last Of The Summer Wine theme tune done in bashment style, or dub if you don't know what your talking about .. or reggae if your name's Phillipa or Jeremy and you're doing your gap year from Uni ..