The Collaborative International Dictionary of English v.0.48:

Unstrung \Unstrung\
   See strung.

WordNet (r) 3.0 (2006):

unstrung
    adj 1: emotionally upset; "the incident left him unstrung and
           incapable of rational effort"

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "unstrung":
   aghast, anemic, appalled, ashen, asthenic, astounded, awed,
   awestricken, awestruck, blanched, bloodless, chicken, cowardly,
   cowed, crushed, dashed, deadly pale, debilitated, demoralized,
   drooping, droopy, dull, effete, etiolated, faint, faintish, feeble,
   flabby, flaccid, floppy, frozen, gone, gray with fear, gutless,
   horrified, horror-struck, imbecile, impotent, intimidated, languid,
   languorous, limber, limp, listless, lustless, marrowless,
   nerveless, neurasthenic, overcome, pale as death, pallid,
   paralyzed, petrified, pithless, pooped, powerless, prostrate,
   prostrated, reduced to jelly, rubbery, sapless, scared stiff,
   scared to death, shaken, shot, shot to pieces, sinewless, slack,
   soft, spineless, strengthless, stricken, stunned, stupefied,
   terrified, terror-crazed, terror-haunted, terror-ridden,
   terror-riven, terror-shaken, terror-smitten, terror-struck,
   terror-troubled, undone, unglued, unhardened, unmanned, unnerved,
   upset, weak, weakly