[KansasGirl]

It is not about Roger Water's drift into insanity but Syd Barrett's, the founder of Pink Floyd. He was an acid freak and drove himself insane. Some people believe he was schizophrenic. Wish You Were Here (Crazy Diamond, specifically) and The Wall were also written about Syd Barrett.

[FreeTally]

It is not about Roger Water's drift into insanity but Syd Barrett's, the founder of Pink Floyd.

Doh! What the heck was I thinking. Of course, I meant Syd, Roger was still in the band. Duh!

[Sword_of_Gideon]

The Wall were also written about Syd Barrett

Not exactly. Per Roger Waters, the Wall has more to do with his falling into the excesses of stardom & his childhood (with a little of Syd thrown in there for good measure).