Depressed; squandered, they say (4)
I believe the answer is:
'depressed' is the definition.
(I've seen this in another clue)
'squandered they say' is the wordplay.
'squandered' becomes 'blew' ('blow' can be a synonym of 'squander').
'they say' shows a homophone (sound like).
'blew' sounds like 'BLUE'.
(Other definitions for blue that I've seen before include "Colour of low spirits" , "Oxbridge sports award" , "Colour; squander" , "Sad - colour" , "Sky-coloured" .)