Table: MIC Range, MIC50, MIC90 (Mg/L) and Percentage of Susceptibility of 100 Clinical

Table 1 Responses by doctors and nurses

Doctors (n=55) Nurses (n=27) p Would never dispense/prescribe a 72.2% 77.8% 0.86 placebo Mode of action of Psychological72% 62% 0.07 placebos

I don’t know 12% 30% Placebo prescription should be 30% 6.6% 0.007 banned Comments indication for the use of aSupplement to a Calming the 0.01 placebo medication (86.1%) patient (43%)

What do you tell the It is a placebo 70% 29% patient when giving I say nothing 2% 42% a placebo? It is a 28% 29% 0.07 medication Placebos are usually or sometimes 84% 63% 0.01 effective.

62% of nurses and 73% of doctors believed that the mode of action of a placebo is through a psychological mechanism (p=0.16). More nurses (30%) than doctors (12%) admitted that they did not know the mode of action of placebos (p=0.07) (Table 1)

50.0% of the doctors thought that there is no gender difference in the response to placebos, whereas 38.6 % thought that placebos are more effective in women while 11.4% thought that they are more effective in men.

Five times as many nurses (30%) as doctors (6.6%) believed that placebo prescription should always be prohibited (p=0.007).

The commonest indication for prescribing a placebo by doctors was as a” supplement to a medication” (86.1%) and for nurses was to “calm the patients” (43%) (p=0.01)

The responses by medical staff and medical residents were not significantly different (Table 2) Table 2 Responses by Medical Staff Versus Medical Residents

Resident Staff Medical Staff p Never prescribed a placebo 63.6 72.00 0.73 I tell the patient "it is a medication" 35.20 60.00 0.38 Placebos never effective 20.00 13.6 0.152 More effective in female patients 43.5 33.30 0.3 Main indication is as “Diagnostic Tool” 84.00 72.7 0.26 Mode of action is psychological 84.00 68.2 0.59 Research is required before its common use 47.9 42.9 0.51

The responses by the 3 medical specialties of the doctors surveyed (Family and Community Medicine, Medicine and Psychiatry) were similar except that fewer psychiatrist (53.8%) than physicians (87.5%) or family physicians (83.5 %) believed that the mode of action of placebos was psychological (p=0.05)

The responses of doctors who practiced for more or less than 5 years were not significantly different except that fewer longer practicing doctors believed that women are more likely to respond to placebos (29.2 % and 42.8% respectively ( p=0.029) ( Table 3) Table 3 Responses according to Duration as a Doctor

< 5 years as a > 5 years as a doctor doctor p Never prescribed a placebo 73.0 50.00 0.17 1I tell the patient "it is a medication" 19.00 27.80 0.18 Placebos never effective 21.50 5.6 0.53 More effective in female patients 42.80 29.2 0.029 The main indication is as “Diagnostic Tool” 47.3 66.7 0.64 Mode of action is psychological 88.10 52.8 0.065 Research is required before its common use 30.5 38.9 0.33

Disturbingly, however, of the doctors who prescribed a placebo, 55.5 % told the patients that it is an actual medication and 22.2% told them “nothing” and only 2% told the patients that it is actually placebos. The nurses were more truthful and fewer of them claimed that the placebo is a medication.