Extremely miserable detectives turned up for doctor (5)
I believe the answer is:
medic
'for doctor' is the definition.
(doctor is a type of medic)
'extremely miserable detectives turned up' is the wordplay.
'extremely' suggests removing the centre (only the extremes of the word are used).
'detectives' becomes 'CID' (abbreviation for Criminal Investigation Department).
'turned up' shows that the letters should be reversed in order.
'miserable' with its centre taken out is 'me'.
'cid' written backwards gives 'dic'.
'me'+'dic'='MEDIC'
(Other definitions for medic that I've seen before include "Eg, doctor" , "He may offer treatment" , "Physician (informal)" , "Health worker" , "What was Basutoland" .)