Driven insane (6)
'driven insane' is the definition.
('craze' can be a synonym of 'drive insane')
This is the entire clue.
(Other definitions for crazed that I've seen before include "out to lunch" , "Driven insane - having network of fine cracks" , "(Of glaze) cracked" , "Finely cracked; mad" .)
(Other definitions for deranged that I've seen before include "Crazy" , "Lunatic" , "Gardened, being quite mad" , "What Ophelia was eventually" , "Disordered; insane" .)