WordNet (r) 3.0 (2006):

antidepressant
    n 1: any of a class of drugs used to treat depression; often
         have undesirable side effects [syn: antidepressant,
         antidepressant drug]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "antidepressant":
   DET, DMT, LSD, Mary Jane, STP, THC, acid, ataractic,
   diethyltryptamine, dimethyltryptamine, gage, ganja, grass,
   hallucinogen, hallucinogenic, hash, hashish, hay, hemp, joint,
   kava, marijuana, mescal, mescal bean, mescal button, mescaline,
   mind-altering drug, mind-blowing drug, mind-expanding,
   mind-expanding drug, morning glory seeds, peyote, pot, psilocin,
   psilocybin, psychedelic, psychic energizer, psychoactive drug,
   psychochemical, psychotomimetic, reefer, roach, stick, tea,
   tranquilizer, weed