WordNet (r) 3.0 (2006):

worsened
    adj 1: changed for the worse in health or fitness; "I feel worse
           today"; "her cold is worse" [syn: worse, worsened]
           [ant: better]
    2: made or become worse; impaired; "troubled by the worsened
       economic conditions"; "the worsened diplomatic relations"

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "worsened":
   aggravated, amplified, annoyed, augmented, broken, burned, burst,
   busted, checked, chipped, cracked, crazed, cut, damaged,
   deliberately provoked, deteriorated, embittered, enhanced,
   enlarged, exacerbated, exasperated, harmed, heated up, heightened,
   hotted up, hurt, impaired, imperfect, in bits, in pieces,
   in shards, increased, injured, intensified, irritated, lacerated,
   magnified, mangled, mutilated, provoked, rent, ruptured, scalded,
   scorched, shattered, slashed, slit, smashed, soured, split, sprung,
   the worse for, torn, weakened, worse, worse off