ill-treated vs abused

ill-treated and abused both are adjectives.

Word	Noun	Adjective	Verb	Adverb
ill-treated	No	Yes	No	No
abused	No	Yes	No	No

As adjectives, ill-treated and abused are synonyms defined as:

Other synonyms of ill-treated include maltreated, mistreated.

ill-treated (adjective)	abused (adjective)
subjected to cruel treatment	subjected to cruel treatment
	used improperly or excessively especially drugs