jamais vu vs mental confusion

jamais vu and mental confusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
jamais vu	Yes	No	No	No
mental confusion	Yes	No	No	No

As nouns, mental confusion is a hypernym of jamais vu; that is, mental confusion is a word with a broader meaning than jamais vu:

jamais vu: the experience of being unfamiliar with a person or situation that is actually very familiar; associated with certain types of epilepsy
mental confusion: a mental state characterized by a lack of clear and orderly thought and behavior

Other hypernyms of jamais vu include confusedness, confusion, disarray, muddiness.

jamais vu (noun)	mental confusion (noun)
the experience of being unfamiliar with a person or situation that is actually very familiar; associated with certain types of epilepsy	a mental state characterized by a lack of clear and orderly thought and behavior