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Describing placebos in patient information leaflets: effects on patients’ beliefs

Felicity L Bishop, Laura McGinn, Cynthia A Graham, Hazel Biggs, Simon Denegri, George T Lewith

Abstract


Background: There are ethical shortcomings to current standard practices regarding the provision of information about placebos in clinical trials. Written information about placebos for clinical trial participants can be incomplete and even misleading. We aimed to develop accurate yet accessible written information about placebos for patients who might participate in clinical trials and to test the effects of such information on patients’ beliefs about placebos.

Methods: With input from 22 patients and public volunteers, a new, “elaborated” information leaflet was developed to provide accessible and evidence-based information about placebos and their possible effects. A “standard” leaflet was also produced which gave a neutral but incomplete description of placebos. In an online experiment 328 participants with chronic health conditions were randomised to read either the elaborated or the standard leaflet. Participants completed validated measures of the credibility and expected effectiveness of placebo treatment for pain and intentions, attitudes, perceived behavioural control and subjective norms towards taking part in a placebo-controlled trial. 

Results: The elaborated leaflet had a significant positive effect on participants’ ratings of the credibility (t(326) = -2.78, p<0.01) and effectiveness (t(326) = -2.59, p<0.05) of placebo treatment for pain.  It had no effect on intentions to take part in placebo-controlled clinical trials. 

Conclusions: The elaborated leaflet provided more comprehensive information about placebos than is commonly provided in current clinical trials. Such a leaflet appears to have greater ethical validity and might increase the magnitude of placebo effects. Further research is needed with participants who are actively considering enrolling in a placebo-controlled trial.


Keywords


Evidence-based information, informed consent, patient education, patient information leaflets, person-centered healthcare, placebos, placebo effects, randomized clinical trials, research ethics

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References


WMA. (2008). Declaration of Helsinki - Ethical principles for medical research involving human subjects. www.wma.net/en/30publications/10policies/b3/

Bishop, F.L., Adams, A.E.M., Kaptchuk, T.J. & Lewith, G.T. (2012). Informed consent and placebo effects: A content analysis of information leaflets to identify what clinical trial participants are told about placebos. PLoS One 7 (6) e39661.

Finniss, D.G., Kaptchuk, T.J., Miller, F.G. & Benedetti, F. (2010). Biological, clinical, and ethical advances of placebo effects. Lancet 375 (9715) 686-695.

Kaptchuk, T.J., Friedlander, E., Kelley, J.M., Sanchez, M.N., Kokkotou, E., Singer, J.P., Kowalczykowski, M., Miller, F.G., Kirsch, I. & Lembo, A.J. (2010). Placebos without deception: A randomized controlled trial in Irritable Bowel Syndrome. PLoS One 5 (12) e15591.

Price, D.D., Finniss, D.G. & Benedetti, F. (2008). A comprehensive review of the placebo effect: Recent advances and current thought. Annual Review of Psychology 59, 565-590.

Benedetti, F. & Amanzio, M. (2011). The placebo response: How words and rituals change the patient's brain. Patient Education and Counseling 84 (3) 413-419.

Pope, J.E., Tingey, D.P., Arnold, J.M.O., Hong, P., Ouimet, J.M. & Krizova, A. (2003). Are subjects satisfied with the informed consent process? A survey of research participants. Journal of Rheumatology 30 (4) 815-824.

Criscione, L.G., Sugarman, J., Sanders, L., Pisetsky, D.S. & St Clair, E.W. (2003). Informed consent in a clinical trial of a novel treatment for rheumatoid arthritis. Arthritis Care & Research 49 (3) 361-367.

Bishop, F.L., Jacobson, E.E., Shaw, J.R. & Kaptchuk, T.J. (2012). Scientific tools, fake treatments, or triggers for psychological healing: How clinical trial participants conceptualise placebos. Social Science & Medicine 74 (5) 767-774.

Barlow, F., Scott, C., Coghlan, B., Lee, P., White, P., Lewith, G.T. & Bishop.F.L. (2011). How the psychosocial context of clinical trials differs from usual care: A qualitative study of acupuncture patients. BMC Medical Research Methodology 11, 79.

White,. P., Bishop, F.L., Prescott, P., Scott, C., Little, P. & Lewith, G.T. (2012). Practice, practitioner or placebo? A multifactorial, mixed methods randomized controlled trial of acupuncture. Pain 153, 455-462.

Benedetti, F. (2008). Mechanisms of placebo and placebo-related effects across diseases and treatments. Annual Review of Pharmacology and Toxicology 48 (1) 33-60.

Kirsch, I. (2004). Conditioning, expectancy, and the placebo effect: Comment on Stewart-Williams and Podd (2004). Psychological Bulletin 130 (2) 341-343.

Kirsch, I. (1997). Response expectancy theory and application: A decennial review. Applied and Preventive Psychology 6 (2) 69-79.

Kirsch, I. & Weixel, L.J. (1988). Double-blind versus deceptive administration of a placebo. Behavioral Neuroscience 102 (2) 319-323.

Diener, H.C., Kronfeld, K., Boewing, G., Lungenhausen,. M., Maier, C., Molsberger, A., Tegenhoff, M., Tram-pisch, H.J., Zenz, M., Meinert, R. & GERAC Migraine Study. (2006). Efficacy of acupuncture for the prophylaxis of migraine: a multicentre randomised controlled clinical trial. Lancet Neurology 5 (4) 310-316.

Papakostas, G.I. & Fava, M. (2009). Does the probability of receiving placebo influence clinical trial outcome? A meta-regression of double-blind, randomized clinical trials in MDD. European Neuropsychopharmacology 19 (1) 34-40.

Sinyor, M., Levitt, A.J., Cheung, A.H., Schaffer, A., Kiss, A., Dowlati, Y. & Lanctot, K.L. (2010). Does inclusion of a placebo arm influence response to active antidepressant treatment in randomized controlled trials? Results from pooled and meta-analyses. Journal of Clinical Psychiatry 71, 270-279.

Kelley, J.M., Kaptchuk, T.J., Cusin, C., Lipkin, S. & Fava, M. (2012). Open-label placebo for major depressive disorder: a pilot randomized-controlled trial. Psychotherapy and Psychosomatics 81, 312-314.

Hummer, M., Holzmeister, R., Kemmler, G., Eder, U., Hofer, A., Kurzhaler, I., Oehl, M., Weiss, E. & Fleischhacker, W.W. (2003). Attitudes of patients with schizophrenia toward placebo-controlled clinical trials. Journal of Clinical Psychiatry 64 (3) 277-281.

Welton, A.J., Vickers, M.R., Cooper, J.A., Meade, T.W. & Marteau, T.M. (1999). Is recruitment more difficult with a placebo arm in randomised controlled trials? A quasirandomised, interview based study. British Medical Journal 318 (7191) 1114-1117.

Ajzen, I. & Madden, T.J. (1986). Prediction of goal-directed behavior: attitudes, intentions, and perceived behavioral control. Journal of Experimental Social Psychology 22, 453-474.

Devilly, G.J. & Borkovec, T.D. (2000). Psychometric properties of the credibility/expectancy questionnaire. Journal of Behavior Therapy and Experimental Psychiatry 31, 73-86.

Francis, J.J., Eccles, M.P., Johnston, M., Walker, A., Grimshaw, J., Foy, R., Kaner, E.F.S., Smith, L. & Bonetti, D. (2004). Constructing questionnaires based on the theory of planned behaviour. A manual for health services researchers. Newcastle upon Tyne: University of Newcastle: Centre for Health Services Research.

Cohen, J. (1992). A power primer. Psychological Bulletin 112 (1) 155-159.

Moerman, D.E. & Jonas, W.B. (2002). Deconstructing the placebo effect and finding the meaning response. Annals of Internal Medicine 136 (6) 471-476.

Marteau, T.M., Dormandy, E. & Michie, S. (2001). A measure of informed choice. Health Expectations 4 (2) 99-108.




DOI: http://dx.doi.org/10.5750/ejpch.v4i4.1145

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