Typist's chair adjusted for doctor (12)
I believe the answer is:
psychiatrist
'for doctor' is the definition.
(psychiatrist is a kind of doctor)
'typist's chair adjusted' is the wordplay.
'adjusted' indicates an anagram.
'typists'+'chair'='typistschair'
'typistschair' anagrammed gives 'PSYCHIATRIST'.
(Other definitions for psychiatrist that I've seen before include "One who treats mental disorders" , "Mental-illness doctor" , "Carl Jung, perhaps" , "Treater of mental illness" , "Doctor of the mind" .)