WordNet (r) 3.0 (2006):

escapist
    n 1: a person who escapes into a world of fantasy [syn:
         escapist, dreamer, wishful thinker]

Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "escapist":
   Don Quixote, Quixote, alcoholic, alternating personality,
   antisocial personality, daydreamer, disordered personality,
   disturbed personality, double personality, dreamer,
   dreamer of dreams, drug user, dual personality,
   emotionally unstable personality, enthusiast, escape artist,
   escapee, escaper, fugitive, hostile personality, hypochondriac,
   hypochondriast, idealist, idiot, imaginary invalid,
   immature personality, inadequate personality, inferior personality,
   lotus-eater, malade imaginaire, maladjusted personality,
   mentally defective personality, moral insanity,
   multiple personality, neuropath, neurotic, neurotic personality,
   paranoid personality, perverse personality, prophet,
   psychoneurotic, psychopath, psychopathic personality, psychotic,
   psychotic personality, rhapsodist, romancer, romantic, romanticist,
   schizoid, schizoid personality, seclusive personality, seer,
   sexual psychopath, shut-in personality, sociopath,
   split personality, utopian, utopianist, utopianizer,
   valetudinarian, valetudinary, visionary, weak personality,
   wishful thinker