self-possessed vs self-collected

self-possessed and self-collected both are adjectives.

Word	Noun	Adjective	Verb	Adverb
self-possessed	No	Yes	No	No
self-collected	No	Yes	No	No

As adjectives, self-possessed and self-collected are synonyms defined as:

Other synonyms of self-possessed include collected, equanimous, poised, self-contained.

self-possessed (adjective)	self-collected (adjective)
in full control of your faculties	in full control of your faculties