highly strung vs overstrung

highly strung and overstrung both are adjectives.

Word	Noun	Adjective	Verb	Adverb
highly strung	No	Yes	No	No
overstrung	No	Yes	No	No

As adjectives, highly strung and overstrung are synonyms defined as:

Other synonyms of highly strung include edgy, high-strung, jittery, jumpy, nervy, restive, uptight.

highly strung (adjective)	overstrung (adjective)
being in a tense state	too tightly strung
	being in a tense state