Table 2.
Summary of findings on the frequency of placebo use.
| Author year | Setting | Type | Placebo use | Definition of use | Frequency or other additional information |
|---|---|---|---|---|---|
| Questionnaire- based quantitative surveys | |||||
| Physicians | |||||
| Goodwin 1979 [19] | Hospital (house officers) | Pure* | 78% | Ever use for pain relief | |
| Gray 1981 [20] | Hospital | Pure | 80% | Ever use | |
| Classen 1985 [23] | Unclear | Pure | 60% | Use 'sometimes' | About 30% less than once a month |
| Classen 1985 [23] | Unclear | Impure | 54% | Use 'sometimes' | |
| Lynöe 1993 [26] | Unclear | Both | 99% | Ever use | None very often, 1% often, 4% rather often, 26% quite rarely, 68% rarely/very rarely |
| Hrobjartsson 2003 [30] | General practice | Both | 86% | During the last year | 38% 1-10 times/year, 48% > 10 times/year |
| Hrobjartsson 2003 [30] | Hospital | Both | 54% | During the last year | 44% 1-10 times/year, 10% > 10 times/year |
| Hrobjartsson 2003 [30] | Specialist practice | Both | 41% | During the last year | 31% 1-10 times/year, 10% > 10 times/year |
| Nitzan 2004 [31] | Hospital/family practice | Pure* | 53% | Use with a minimum frequency of once a year | 37% once a month or more often† |
| Sherman 2007 [33] | Medical school faculty | Both | 45% | Ever use | 15% 1-10×, 8% > 10×, 22% not at all during last year |
| Tilburt 2008 [34] | Specialist practice | Both | 80% | Ever use | 34% = once a month, 28% 2-3 times/month, 18% = once a week |
| Bernateck 2009 [35] | Hospital | Pure | 52% | Use with a minimum frequency of once a year | 40% 1-2 times/year, 9% 1-2 times/month, 4% more often |
| Fässler 2009 [37] | Primary care | Pure | 17% | Ever use | 93% once a month or less often |
| Fässler 2009 [37] | Primary care | Impure | 57% | Ever use | |
| Nurses | |||||
| Goldberg 1979 [18] | Hospital | Pure | 51% | Ever use | 44% with current use or use in the last 6 months |
| Goodwin 1979 [19] | Hospital | Pure* | 82% | Ever use for pain relief | |
| Gray 1981 (sample 1) [20] | Hospital | Pure | 80% | Ever use | |
| Gray 1981 (sample 2) [20] | Hospital | Pure | 89% | At least once during the last 5 years | 63% during the last year |
| Saupe 1985 [24] | Hospital | Pure | 100% | Ever use | 79% once or less per month, 21% more often |
| Ernst 1997 [27] | Unclear | Pure | 57% | Ever use | |
| Ernst 1997 [27] | Unclear | Both | 68% | Ever use | 12% during the last year |
| Nitzan 2004 [31] | Hospital | Pure* | 71% | Use with a minimum frequency of once a year | 37% once a month or more often† |
| Bernateck 2009 [35] | Hospital | Pure | 87% | Use with a minimum frequency of once a year | 45% 1-2 times/year, 33% 1-2 times/month, 9% more often |
| Interns | |||||
| Berger 1999 [28] | Hospital | Pure | 16% | Ever witnessed use | Only 2% (1/47) had actually given a placebo |
| Substudies with prospective screening of medical records of hospital patients | |||||
| Goodwin 1979 [19] | Hospital | Pure* | 0.3% | During 6 months (prospective) | |
| Lange 1981 [21] | Psychiatric hospital | Pure | 5.1% | During 12 months (prospective) | 6.1% in women, 3.9% in men |
* Limitation to pure placebo not explicitly stated but questions/report with clear focus on pure placebo use.
† Numbers related to both physicians and nurses.