title: A double-blind methodology for biofeedback research.
mesh_terms: D001676:Biofeedback, Psychology; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D009892:Opium / Q000031:analogs & derivatives*; D012107:Research Design; D013375:Substance Withdrawal Syndrome / Q000628:therapy*
chemical_list: D009892:Opium