The English Malady?

Schizophrenia, mental problems, low self esteem, alcohol, LSD and other drugs, and lots of fantastic (and not so fantastic!) rock music!
Now is there a connection here, and is it something about England?
Clinton Heylin is at least trying to describe the mental problems - music connection in his book "All the Madmen: Barrett, Bowie, Drake, the Floyd, The Kinks, The Who and the Journey to the Dark Side of English Rock" (Constable 2012).

There are some sidetracks in this story (a.o. Peter Green), but the soundtrack may look like this:
Nick Drake: "Pink Moon"
Syd Barrett: "The Madcap Laughs"
Kinks: "Muswell Hillbillies"
David Bowie: "Ziggy Stardust"
Pink Floyd: "Dark Side of the Moon"
The Who: "Quadrophenia"

We get to hear about Soft Machine, who spent some days in the studio to record for "The Madcap Laughs" (not much left on the album though).
And Heylin is not afraid to put it bluntly, he says that David Gilmour and Roger Waters hijacked Syd Barrett´s album, making the final result too much their own. Right or wrong?

Probably a better read for the ones who really know these artists and their recordings (yes of course, all of you do, but I mean the other ones), since it is pretty detailed. Me, I realized that I did not know my Kinks and Who as well as I thought (not too late is it?).

To rub it in, Heylin´s appendix is called: "A fast rewind through 400 years of the English malady".