| PMC full text: | Pain. Author manuscript; available in PMC 2014 Dec 1. Published in final edited form as: |
Table 1
Return to: The Magnitude of Nocebo Effects in Pain
Characteristics of included studies, including title, number of participants, population, pain, design, agent, and framing of suggestions.
| Study | N*1 | Population | Pain | Design | Agent | Exact framing of suggestions |
|---|---|---|---|---|---|---|
|
Benedetti et
al. (1997) | 36 | Thoracic patients | Post-operative pain | Double-blind Randomized Between subjects*2 | Open saline injection | “Told that it [the injection] produced a pain increase within 30 min”. |
|
Benedetti et
al. (2003) | 26 | Healthy volunteers | Tourniquet ischemic pain | Double-blind Randomized Between subjects | Saline injection | “Told that it was a drug that increased pain”. |
|
Benedetti et
al. (2006) | 25 | Healthy volunteers | Tourniquet ischemic pain | Double-blind Randomized Between subjects | Inert talc pill 5 min. before pain stimulation | “It was a powerful vasoconstrictor further increasing the tourniquet-induced ischemia […] told that, because of the quick vasoconstriction, this would induce a faster and larger increase of pain intensity, so that a quite strong hyperalgesic effect should be expected […] told that they could give up at any time”. |
|
Colloca et al.
(2008) | 29 | Healthy women | Electrical shock | Single-blind Randomized Within subjects | Sham electrode | “Told that a green light would anticipate a stimulus that was made painful by the stimulation of the middle finger […] that the green light anticipated the activation of the electrode that in turn induced a hyperalgesic effect”. |
|
Colloca et al.
(2010) | 46 | Healthy volunteers | Electrical shock | Single-blind Pseudo- randomized Within subjects | Sham electrode | “Informed that the activation of electrodes attached to the ankle would […] increase their […] painful perception when a red light was displayed”. Control: “Told that a yellow light would indicate the deactivation of the ankle electrodes and thus that no treatment would be given”. |
|
Elsenbruch et
al. (2012) | 32 | Healthy women | Rectal distension | Single-blind Randomized Between subjects | Inert substance (sodium chloride) | “Informed that it [the injection] contained sodium chloride, but were also told that the aim of the study was to verify our previous observation that pain ratings increased significantly in the majority of subjects over time, i.e., that sensitization occurred, over the course of the 2-day experiment”. |
|
Johansen et
al. (2003) | 34*3 | Healthy men | Tourniquet ischemic pain | Double-blind Randomized Between subjects | Saline injection | ”Told that it was a substance that would increase the pain”. |
|
Kong et al.
(2008) | 13 | Healthy volunteers | Heat pain | Single-blind Pseudo- randomized Within subjects | Sham acupuncture | “After treatment we told subjects they would be receiving the same [increased] stimuli series administered before treatment”. |
|
Vase et al.
(2003) | 13 | Women with IBS | Rectal distension | Double-blind Randomized Within subjects | Sterile surgical lubricant/saline jelly | “The agent you have just been giving is known to significantly increase pain in some patients”. |
|
Vögtle et al.
(2013) | 80 | Healthy volunteers | Pressure pain | Single-blind Randomized between subjects | Ointment | Verbal suggestion: “The ointment was designed to intensify the sensitivity of the skin in patients with sexual dysfunction”. Social observation: “The influence of a nonverbal instruction on the experimental procedure was being tested”. |
*2“Between subjects” and “within subjects” designs as reported in the study and included in the calculations.
*3Dropout of participants over time, After 5 min, 17 participants in each group rated their pain and after 10 min, 14 and 13 participants rated their pain.