Headache: the Placebo Effects in the Control Groups in Randomized Clinical Trials; an Analysis of Systematic Reviews

Abstract

The mean recovery rate in the control groups was 36%. The recovery rate varied substantially between type of intervention and patients.

Informed Consent and Placebo Effects: A Content Analysis of Information Leaflets to Identify What Clinical Trial Participants Are Told about Placebos

“…Trials in conditions that are known to have strong placebo responses ( e.g . IBS [3], [4], musculoskeletal pain [5], [6], depression [7], [8]) might emphasise the possible effects and well-established mechanisms of placebo, while trials in conditions that are less responsive to placebos might emphasise the processes that can lead participants in the placebo group to perceive improvement ( e.g . interventions that both the placebo and target treatment group receive).…”

“…those changes in a person's health status that result from the meaning and hope the person attributes to a procedure or event in a health care setting [1], [2]. These effects can be large, for example in irritable bowel syndrome [3], [4], musculoskeletal pain [5], [6], and depression [7], [8], and are underpinned by increasingly well-understood psychological and neurobiological mechanisms [9]–[11]. What trial participants are told about placebos is an ethical and a methodological question.…”

Noninvasive Sphenopalatine Ganglion Block for Acute Headache in the Emergency Department: A Randomized Placebo-Controlled Trial

“…Placebo effect has been well documented in headache trials; however, these are still striking results to be achieved with a true placebo in only 15 minutes. 21,22 Half of the patients in the placebo group versus 61% in the bupivacaine group had a 20-mm or greater reduction in headache at 15 minutes. More than 26% of patients in both the bupivacaine group and the saline solution group reported complete resolution of headache at 15 minutes.…”

“…Although a substantial placebo effect is common in studies of headache therapy, these results are impressive for a true placebo. 21,22 It is possible that the sphenopalatine ganglion was stimulated mechanically because of the pressure of the spray or even by the absorption of saline solution itself, producing a therapeutic effect. Using a sham device that sprays to a different location than the sphenopalatine ganglion may be a better control for assessing a difference between groups.…”

Triggerpunkt-Therapie und Manuelle Lymphdrainage in der Migräne-Prophylaxe

“…Aus randomisierten kontrollierten Studien zur Behandlung des Kopfschmerzes ist bekannt, dass bei Placebo-Kontrollgruppen eine Responder-Rate von 30-50 % zu beobachten ist [37,38]. Daher ist ein Teil der beobachten positiven Effekte möglicherweise auch Ausdruck dieses Placebo-Effektes und nicht der spezifischen therapeutischen Maßnahmen.…”