title: Letter: Tryptophan in depression.
mesh_terms: D003863:Depression / Q000188:drug therapy* / Q000652:urine; D006801:Humans; D008734:Methoxyhydroxyphenylglycol / Q000652:urine; D014364:Tryptophan / Q000627:therapeutic use*
chemical_list: D008734:Methoxyhydroxyphenylglycol; D014364:Tryptophan