The Collaborative International Dictionary of English v.0.48:

Disturb \Dis*turb"\, v. t. [imp. & p. p. Disturbed; p. pr. &
   vb. n. Disturbing.] [OE. desturben, destourben, OF.
   destorber, desturber, destourber, fr. L. disturbare,
   disturbatum; dis- + turbare to disturb, trouble, turba
   disorder, tumult, crowd. See Turbid.]
   1. To throw into disorder or confusion; to derange; to
      interrupt the settled state of; to excite from a state of
      rest.
      [1913 Webster]

            Preparing to disturb
            With all-cofounding war the realms above. --Cowper.
      [1913 Webster]

            The bellow's noise disturbed his quiet rest.
                                                  --Spenser.
      [1913 Webster]

            The utmost which the discontented colonies could do,
            was to disturb authority.             --Burke.
      [1913 Webster]

   2. To agitate the mind of; to deprive of tranquillity; to
      disquiet; to render uneasy; as, a person is disturbed by
      receiving an insult, or his mind is disturbed by envy.
      [1913 Webster]

   3. To turn from a regular or designed course. [Obs.]
      [1913 Webster]

            And disturb
            His inmost counsels from their destined aim.
                                                  --Milton.

   Syn: To disorder; disquiet; agitate; discompose; molest;
        perplex; trouble; incommode; ruffle.
        [1913 Webster]

WordNet (r) 3.0 (2006):

disturbed
    adj 1: having the place or position changed; "the disturbed
           books and papers on her desk"; "disturbed grass showed
           where the horse had passed"
    2: afflicted with or marked by anxious uneasiness or trouble or
       grief; "too upset to say anything"; "spent many disquieted
       moments"; "distressed about her son's leaving home"; "lapsed
       into disturbed sleep"; "worried parents"; "a worried frown";
       "one last worried check of the sleeping children" [syn:
       disquieted, distressed, disturbed, upset, worried]
    3: emotionally unstable and having difficulty coping with
       personal relationships [syn: disturbed, maladjusted]
    4: affected with madness or insanity; "a man who had gone mad"
       [syn: brainsick, crazy, demented, disturbed, mad,
       sick, unbalanced, unhinged]

Moby Thesaurus II by Grady Ward, 1.0:

178 Moby Thesaurus words for "disturbed":
   abashed, abroad, adrift, afflicted, aggravated, agitated,
   all-overish, amiss, angry, annoyed, anxious, anxioused up,
   apprehensive, askew, astray, at sea, awry, balled-up, batty, beset,
   bewildered, bonkers, bothered, brain-damaged, brain-injured,
   browned-off, bugged, burnt-up, cast down, catatonic, certifiable,
   chafed, chagrined, chaotic, chapfallen, clueless, cockeyed,
   concerned, confused, convulsed, crazy, depressed, deranged,
   disarranged, discomfited, discomforted, discomposed, disconcerted,
   dislocated, dismayed, disordered, disorderly, disorganized,
   disoriented, disquieted, distracted, distraught, distressed,
   embarrassed, exasperated, excited, fearful, feverish, fidgety,
   flurried, flustered, fluttered, foreboding, fussed, galled, griped,
   guessing, haywire, hung up, hypochondriac, hysteric, ill at ease,
   in a fix, in a jumble, in a maze, in a pickle, in a pother,
   in a pucker, in a scrape, in a stew, in a sweat, in a swivet,
   in a tizzy, in disorder, insane, irked, irritated, jittery,
   jumbled, jumpy, lost, mad, maladjusted, manic-depressive, mazed,
   mentally ill, mentally sick, miffed, misgiving, misplaced,
   mixed-up, mortified, nervous, nervy, nettled, neurasthenic,
   neurotic, nuts, off the track, on tenterhooks, on the fritz,
   out of countenance, out of gear, out of joint, out of kelter,
   out of kilter, out of order, out of place, out of tune,
   out of whack, overanxious, overapprehensive, paranoiac, paranoid,
   peeved, perplexed, perturbed, phobic, piqued, provoked,
   psychasthenic, psychoneurotic, psychopathic, psychotic, put-out,
   put-upon, rattled, resentful, restless, riled, roiled, roily,
   ruffled, schiz, schizoid, schizophrenic, schizy, screwy, shaken,
   shaken up, shook, shuffled, solicitous, stirred up, strained,
   suspenseful, tense, troubled, troublous, turbid, turbulent,
   turned around, unbalanced, uncomfortable, uneasy, unpeaceful,
   unquiet, unsettled, upset, vexed, without a clue, worried,
   zealous