In their broadest sense, placebo effects are healing outcomes derived from the ritual of medicine, the patient-provider relationship and the power of the therapeutic and bodily imagination (Kaptchuk, 2011
). Placebos are both the tools and subjects of scientific research. Administering placebos to patients can elicit beneficial effects including the reduction of symptoms such as chronic pain (Finnis et al., 2010
), insomnia (Bélanger et al., 2007
) and depression (Kirsch et al., 2008
). For neuroscientists, psychologists and anthropologists, placebos constitute a means to examine how contextual factors contribute to healing processes and to test theories about how the administration of placebos triggers various salutary effects. For clinical researchers, placebos are essential tools in randomised clinical trials (RCTs), used to control for contextual and psychological components of healing and thus isolate the specific effect of a new drug or treatment. From the perspective of biomedical triallists then, placebos are research tools and their effects must be controlled for. But what about those people who volunteer to take part in clinical research, those who can experience placebo effects at first hand: what do placebos mean to their recipients? This paper explores how participants in one RCT conceptualised placebos and the implications of this for both practical applications and theoretical understandings of placebos.
According to the Common-Sense Model of illness cognition, people construct cognitive and emotional representations of symptoms which they use to guide their selection and evaluation of coping procedures (Leventhal et al., 1992
). According to the extended version of the model, people also construct representations of different coping procedures including medicines, and these representations influence uptake of and adherence to treatment (Horne & Weinman, 2002
). Thus we might reasonably expect people to construct representations of placebos, and for these representations to guide their actions. The few studies that have been published in this area do indeed suggest that people develop (often limited) ideas about placebos and that these ideas can shape their behaviour, particularly in relation to participation in RCTs.
Existing research suggests that lay people have somewhat limited understandings of placebos and their effects. Focus group participants in Australia and Japan were described as confused by and unfamiliar with the use of placebos in medical research (Asai et al., 2004
; Ellis & Butow, 1998
). In surveys, rheumatology patients (and nurses) as well as general practice patients have been described as underestimating the size of the placebo effect and having little knowledge about it (Berthelot et al., 2001
; Chen & Johnson, 2009
). While there is a paucity of evidence in this area, it seems that people may have limited knowledge about placebos and yet be willing to accept their use in medical research: A public consultation in Canada concluded that participants viewed placebo-controlled trials as valuable research tools and accepted their use (with informed consent) depending on the severity of the condition and the availability of alternative control treatments (Huston, 2007
). Furthermore, potential trial participants’ attitudes towards placebos may influence their willingness to take part in placebo-controlled RCTs (Hummer et al., 2003
; Welton et al., 1999
). For example, in an interview study with people with schizophrenia, some respondents reported being encouraged to take part by the chance of getting a placebo (rather than active medication) while others reported being put off by not knowing whether or not they were taking placebo (Hummer et al., 2003
). This suggests the need to adopt a broader perspective that goes beyond documenting the accuracy (or absence) of knowledge about placebos and instead focuses on how RCT participants conceptualise placebos and their effects.
How RCT participants conceptualise placebos also has implications for ethical research conduct. If a participant does not understand that the benefits of treatment and placebo might be equal, then they cannot be said to have given informed consent to take part in a placebo-controlled trial. Disparities between medical and lay understandings of technical RCT processes such as randomisation and clinical equipoise have been documented in many settings (Featherstone & Donovan, 1998
; Robinson et al., 2005
) and are often attributed to the therapeutic misconception, whereby RCT participants mistakenly attribute therapeutic motives to trial physicians and investigators (Appelbaum et al., 1987
). There is some evidence that trial participants also hold beliefs about placebos that are incorrect and/or at odds with researchers’ beliefs (Criscione et al., 2003
; Pope et al., 2003
). For example, in a placebo-controlled trial in arthritis, 87% of participants understood that some people in the trial would receive a placebo but only 50% correctly disagreed with a statement that they would definitely receive an active treatment (Criscione et al., 2003
). Quantitative work can establish the existence and prevalence of participants’ misunderstandings about placebos in RCTs. However, qualitative work with RCT participants is needed to explore how their views of placebos differ from researchers’ views and to suggest reasons for and consequences of any such differences. We therefore analysed qualitative data from one RCT that investigated both placebo effects and acupuncture and aimed 1) to identify the ways in which participants conceptualised placebos and 2) to suggest reasons for and possible consequences of different ways of thinking about placebos.