title: Expectation-induced placebo responses fail to accelerate wound healing in healthy volunteers: results from a prospective controlled experimental trial.
abstract: Placebo responses have been shown to affect the symptomatology of skin diseases. However, expectation-induced placebo effects on wound healing processes have not been investigated yet. We analysed whether subjects' expectation of receiving an active drug accelerates the healing process of experimentally induced wounds. In 22 healthy men (experimental group, n = 11; control group, n = 11) wounds were induced by ablative laser on both thighs. Using a deceptive paradigm, participants in the experimental group were informed that an innovative 'wound gel' was applied on one of the two wounds, whereas a 'non-active gel' was applied on the wound of the other thigh. In fact, both gels were identical hydrogels without any active components. A control group was informed to receive a non-active gel on both wounds. Progress in wound healing was documented via planimetry on days 1, 4 and 7 after wound induction. From day 9 onwards wound inspections were performed daily accompanied by a change of the dressing and a new application of the gel. No significant differences could be observed with regard to duration or process of wound healing, either by intraindividual or by interindividual comparisons. These data document no expectation-induced placebo effect on the healing process of experimentally induced wounds in healthy volunteers.
authors.affiliation: Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Vits
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Dissemond
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Schadendorf
authors.affiliation: Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Kriegler
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Körber
authors.affiliation: Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, Essen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Schedlowski
authors.affiliation: Department of Dermatology, Venereology and Allergology, University Hospital Essen, Essen, Germany.
authors.forename: Elvir
authors.initials: E
authors.lastname: Cesko
mesh_terms: D000328:Adult; D001458:Bandages; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000627:therapeutic use*; D008297:Male; D015990:Placebo Effect; D011446:Prospective Studies; D014945:Wound Healing / Q000502:physiology*; D014947:Wounds and Injuries / Q000523:psychology / Q000628:therapy*; D055815:Young Adult
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: Expectation; Placebo; Wound healing