title: Duration of illness and response to tryptophan in Parkinson's disease.
mesh_terms: D004325:Dreams / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D010300:Parkinson Disease / Q000188:drug therapy* / Q000523:psychology; D011569:Psychiatric Status Rating Scales; D014364:Tryptophan / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D014364:Tryptophan