Aspired to treat depression (7)
I believe the answer is:
despair
'depression' is the definition.
(thesaurus)
'aspired to treat' is the wordplay.
'to treat' indicates anagramming the letters.
'aspired' anagrammed gives 'DESPAIR'.
(Other definitions for despair that I've seen before include "Resignation" , "Lose or lack hope" , "Opposite of 10" , "Give up hope" , "Hopeless" .)