title: Tryptophan dosage critical for its antidepressant effect.
mesh_terms: D002986:Clinical Trials as Topic; D003863:Depression / Q000188:drug therapy*; D004311:Double-Blind Method; D004357:Drug Synergism; D006801:Humans; D007099:Imipramine / Q000627:therapeutic use; D009536:Niacinamide / Q000627:therapeutic use; D014364:Tryptophan / Q000008:administration & dosage*
chemical_list: D009536:Niacinamide; D014364:Tryptophan; D007099:Imipramine