Under the influence, doctor doesn't (6)
I believe the answer is:
stoned
'under the influence' is the definition.
(I've seen this before)
'doctor doesn't' is the wordplay.
'doctor' indicates anagramming the letters.
'doesnt' with letters rearranged gives 'STONED'.
(Other definitions for stoned that I've seen before include "Slangily drunk or drugged" , "Incapable from drug-taking" , "Like Olive perhaps" , "Slangily drunk in Ostend" , "with jewels" .)