Drunk amused when leader is changed (7)

I believe the answer is:

pickled

I'm a little stuck... Click here to teach me more about this clue!

'drunk' is the definition.
(pickled can informally mean drunk)

I can't explain the rest of the clue.

(Other definitions for pickled that I've seen before include "Preserved - drunk" , "Drunk (as a gherkin?)" , "Preserved in vinegar or brine" , "Soused" , "Preserved in liquid" .)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app