title: Letter: Tryptophan and allopurinol in the treatment of depression.
mesh_terms: D000328:Adult; D000493:Allopurinol / Q000008:administration & dosage / Q000627:therapeutic use*; D003863:Depression / Q000188:drug therapy*; D004341:Drug Evaluation; D004359:Drug Therapy, Combination; D006801:Humans; D008297:Male; D008875:Middle Aged; D014364:Tryptophan / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000493:Allopurinol; D014364:Tryptophan