Disturbed state of mind during a fever (8)
I believe the answer is:
delirium
'disturbed state of mind during a fever' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for delirium that I've seen before include "Hallucinatory state of wild excitement" , "Febrile mental confusion" , "Wild state of mind" , "Feverish state" , "state of ecstasy" .)