regression vs psychological medicine

regression and psychological medicine both are nouns.

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

regression (noun)	psychological medicine (noun)
returning to a former state	the branch of medicine dealing with the diagnosis and treatment of mental disorders
the relation between selected values of x and observed values of y (from which the most probable value of y can be predicted for any value of x)
(psychiatry) a defense mechanism in which you flee from reality by assuming a more infantile state
an abnormal state in which development has stopped prematurely