Irving Kirsch

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BACKGROUND Meta-analyses of antidepressant medications have reported only modest benefits over placebo treatment, and when unpublished trial data are included, the benefit falls below accepted criteria for clinical significance. Yet, the efficacy of the antidepressants may also depend on the severity of initial depression scores. The purpose of this(More)
Placebo analgesia was produced by conditioning trials wherein heat induced experimental pain was surreptitiously reduced in order to test psychological factors of expectancy and desire for pain reduction as possible mediators of placebo analgesia. The magnitudes of placebo effects were assessed after these conditioning trials and during trials wherein(More)
Hypnotic and nonhypnotic suggestibility were investigated in 2 experiments. In Experiment 1, nonhypnotic suggestibility was suppressed when measured after hypnotic suggestibility, whereas hypnotic suggestibility was not affected by the order of assessment. Experiment 2 confirmed a small but significant effect of hypnosis on suggestibility when nonhypnotic(More)
Hypnotic responses have been attributed to 2 mechanisms that are characterized as dissociative. In E. R. Hilgard's (1986) neodissociation theory, responses are hypothesized to be due to a division of consciousness into 2 or more simultaneous streams, separated by an amnesic barrier that prevents access to suggestion-related executive functions, monitoring(More)
In this study, a well established expectancy manipulation model was combined with a novel placebo intervention, a validated sham acupuncture needle, to investigate the brain network involved in placebo analgesia. Sixteen subjects completed the experiment. We found that after placebo acupuncture treatment, subjective pain rating reduction (pre minus post) on(More)
OBJECTIVE To investigate whether placebo effects can experimentally be separated into the response to three components-assessment and observation, a therapeutic ritual (placebo treatment), and a supportive patient-practitioner relationship-and then progressively combined to produce incremental clinical improvement in patients with irritable bowel syndrome.(More)
Contrary to some recent claims, the placebo effect is real and in some cases very substantial. Placebo effects can be produced or enhanced by classical conditioning, but consistent with virtually all contemporary conditioning theories, these effects are generally mediated by expectancy. Expectancy can also produce placebo effects that are inconsistent with(More)