catathymia vs mental state

catathymia and mental state both are nouns.

Word	Noun	Adjective	Verb	Adverb
catathymia	Yes	No	No	No
mental state	Yes	No	No	No

As nouns, mental state is a hypernym of catathymia; that is, mental state is a word with a broader meaning than catathymia:

catathymia: A state in which mental processes are under the control of the emotions.
mental state: (psychology) a mental condition in which the qualities of a state are relatively constant even though the state itself may be dynamic

Other hypernyms of catathymia include mental condition, psychological condition, psychological state.

catathymia (noun)	mental state (noun)
A state in which mental processes are under the control of the emotions.	(psychology) a mental condition in which the qualities of a state are relatively constant even though the state itself may be dynamic