psychiatry vs psychological medicine

psychiatry and psychological medicine both are nouns.

Word	Noun	Adjective	Verb	Adverb
psychiatry	Yes	No	No	No
psychological medicine	Yes	No	No	No

As nouns, psychiatry and psychological medicine are synonyms defined as:

psychiatry and psychological medicine: the branch of medicine dealing with the diagnosis and treatment of mental disorders

Other synonyms of psychiatry include psychopathology.

psychiatry (noun)	psychological medicine (noun)
the branch of medicine dealing with the diagnosis and treatment of mental disorders	the branch of medicine dealing with the diagnosis and treatment of mental disorders