I am sane - suffering loss of memory (7)
I believe the answer is:
amnesia
'loss of memory' is the definition.
(I've seen this in another clue)
'i am sane suffering' is the wordplay.
'suffering' indicates an anagram.
'i'+'am'+'sane'='iamsane'
'iamsane' is an anagram of 'AMNESIA'.
(Other definitions for amnesia that I've seen before include "Inability to recall" , "Is a name (anag.)" , "Am I sane? (anag)" , "Severe forgetfulness" , "Partial or total loss of memory" .)