Disciple, fellow with nothing left, more depressed (8)
I believe the answer is:
follower
'disciple' is the definition.
(I've seen this before)
'fellow with nothing left more depressed' is the wordplay.
'fellow' becomes 'F' (abbreviation - of a society etc.).
'with' means one lot of letters go next to another.
'nothing' becomes 'O' (looks like zero - 0).
'left' becomes 'l' (common abbreviation).
'more depressed' becomes 'lower' ('low' can be similar in meaning to 'depressed').
'f'+'o'+'l'+'lower'='FOLLOWER'
(Other definitions for follower that I've seen before include "One accepts the leadership of another" , "fan" , "Disciple" , "A devotee or a pursuer" , "Person who succeeds" .)