monomania vs possession

monomania and possession both are nouns.

Word	Noun	Adjective	Verb	Adverb
monomania	Yes	No	No	No
possession	Yes	No	No	No

As nouns, monomania and possession are synonyms defined as:

monomania (noun)	possession (noun)
a mania restricted to one thing or idea	anything owned or possessed
	the act of having and controlling property
	(sport) the act of controlling the ball (or puck)
	the trait of resolutely controlling your own behavior
	a territory that is controlled by a ruling state
	a mania restricted to one thing or idea
	being controlled by passion or the supernatural