shows the composition of the group. We have summarised the data from the questionnaire under six headings.
Demographic and professional data for respondents to questionnaire on use of placebos
Frequency—When we planned the study we assumed that the use of placebo was not widespread and would not exceed 10%. Among our 89 respondents, however, 53 (60%) admitted using a placebo (95% confidence interval 49% to 70%). The age and sex of respondent did not affect results. In total, 53% of doctors and 71% of nurses reported using a placebo. Among users, 33 (62%; 37% of the total sample) used a placebo as often as once a month or more. Differences between physicians and nurses in reported use and frequency of use of placebo did not attain significance.
Perceived therapeutic value—Of those who used a placebo, most (48 of 51 who answered the question, or 94%) found that it was either generally (17, or 33%) or occasionally (31, or 61%) effective.
Information given to patients—Of those using the placebo, 36 (68%) tell the patient that he or she is receiving a real medicine, and nine (17%) say nothing at all. The rest either identify the placebo as such (two, or 4%) or tell the patient that he or she is receiving a non-specific medicine (six, or 11%).
Circumstances of use—We found a wide range of applications for placebo (). Placebos were given in the form of saline infusions or intramuscular injections; paracetamol or vitamin C tablets instead of the ordinarily prescribed medication; sugar or artificial sweetener pills; or prepared placebo tablets. The medical conditions for which the placebos were used included anxiety, pain (including abdominal), agitation, vertigo, sleep problems, asthma, contractions in labour, withdrawal from recreational drugs, and angina pectoris (when the blood pressure was too low to allow for vasodilators). The stated value as a diagnostic tool, referred to in , was to distinguish organic from psychogenic or simulated arthralgia, seizure disorder, and abdominal or other pain.
Circumstances in which placebo was administered. Figures are number (percentage of those who reported use) of respondents*
Ethical stance—Of 79 responses on ethics, only four (5%) thought that the use of placebos should be categorically prohibited. Most of the others considered placebo use conditional on certain circumstances, such as prior experience (26, or 33%), notifying patients of receipt of a placebo (23, or 29%), or evidence from research that the placebo was effective (19, or 24%).
Perceived mechanism of action—Respondents were permitted to propose more than one mechanism of action for placebos. Of 83 responses, most (62, or 75%) attributed the effect purely to psychological mechanisms. An additional nine (11%) respondents suggested a combination of psychological and biochemical effects.