Passionate artist's over depression (6)
I believe the answer is:
ardent
'passionate' is the definition.
('ardent' can be similar in meaning to 'passionate')
'artist's over depression' is the wordplay.
'artist' becomes 'ra' (Royal Academician, member of Royal Academy of Arts).
'over' shows that the letters should be reversed in order.
'depression' becomes 'dent' ('dent' can be a synonym of 'depression'**).
'ra' written backwards gives 'ar'.
'ar'+'dent'='ARDENT'
(Other definitions for ardent that I've seen before include "Passionate, full of feeling" , "Enthusiastic or passionate" , "passion" , "Passionate and glowing" , "Fiery and zealous" .)