bipolar disorder vs manic-depressive psychosis

bipolar disorder and manic-depressive psychosis both are nouns.

Word	Noun	Adjective	Verb	Adverb
bipolar disorder	Yes	No	No	No
manic-depressive psychosis	Yes	No	No	No

As nouns, bipolar disorder and manic-depressive psychosis are synonyms defined as:

bipolar disorder and manic-depressive psychosis: a mental disorder characterized by episodes of mania and depression

Other synonyms of bipolar disorder include manic depression, manic depressive illness.

bipolar disorder (noun)	manic-depressive psychosis (noun)
a mental disorder characterized by episodes of mania and depression	a mental disorder characterized by episodes of mania and depression