title: Letter: Unipolar affective illness.
mesh_terms: D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry; D003863:Depression / Q000378:metabolism*; D006801:Humans; D009474:Neurons / Q000378:metabolism; D014364:Tryptophan / Q000172:deficiency
chemical_list: D014364:Tryptophan