decentration vs mental state

decentration and mental state both are nouns.

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

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

decentration: Jean Piaget's theory of cognitive development where a child slowly moves away from an egocentric world to a world shared with others.
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 decentration include mental condition, psychological condition, psychological state.

decentration (noun)	mental state (noun)
Jean Piaget's theory of cognitive development where a child slowly moves away from an egocentric world to a world shared with others.	(psychology) a mental condition in which the qualities of a state are relatively constant even though the state itself may be dynamic