Keeper first dropped in depressing experience (5)
I believe the answer is:
owner
'keeper' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for owner that I've seen before include "Title-holder" , "Person having property" , "Title holder?" , "The one in lawful possession" , "One who possesses" .)