Placebos are widely used in medical practice, although the exact numbers are not known. Surveys have shown that somewhere between 57-97% of doctors admit to using placebos in their clinical practice. Placebos would not be used so prevalently if they did not have positive effects, but it’s vitally important that placebos are used as ethically as possible to avoid harming the doctor-patient relationship. Here, we outline different types of placebo usage, the ethical considerations and the current medical guidelines for placebos in clinical practice.

More than just sugar pills

There are many different ways to classify placebos, but the most relevant clinical classification is pure vs impure placebos.

Pure placebos are what we traditionally think of as placebos: sugar pills, saline injections and sham surgery. Basically, any intervention that is completely pharmacologically – or surgically – inert.

So what about impure placebos? Impure placebos are interventions with clear effects for certain conditions, but they are being prescribed for conditions upon which they do not have any known physiological effects. A 2013 survey, listed the following examples of impure placebos:

  • Antibiotics for suspected viral infections inc. colds
  • Non-essential physical examination
    Non-essential technical examinations i.e. blood tests, x-rays etc.
  • Nutritional supplements
  • Probiotics for diarrhoea
  • Positive suggestions
  • Peppermint pills for pharyngitis
  • Sub-clinical doses of effective therapies
  • Off-label uses of a potentially effective therapy
  • Complementary and alternative medicine whose effectiveness is not evidence-based
  • Conventional medicine whose effectiveness is not evidence-based

Surveys have demonstrated that clinical use of impure placebos is far more prevalent, than pure placebos, however there are ethical considerations to take into account before using any placebo.

The ethics of placebo use in clinical practice

Informed consent

Informed consent is by far the most obvious ethical consideration when using placebos. A patient should not be deceived and should be allowed to give informed consent where possible. To issue a placebo without the consent of the patient is to undermine their autonomy and to risk damaging the doctor-patient relationship if the patient were to discover the deceit.

Risk vs benefit

Before issuing any treatment, the risks and benefits must be evaluated by the prescribing physician. This also applies to the use of placebos. Studies have shown clear benefit for some patients using placebos, however, placebos should be used responsibly. Patients should not discontinue conventional medical treatment to be given placebos – especially if this may result in harm to the patient or an exacerbation of symptoms. However, there are circumstances in which placebos the benefits may outweigh the risks i.e. when there is no other treatment available, where other treatments have been found ineffective, in addition to conventional treatments.

Scientific foundation

In modern medical practice, it is important that treatments are evidence-based where possible and have a strong scientific foundation. Despite common misconceptions, the placebo effect has got a large evidence base. Every placebo-controlled trial demonstrates the presence of a placebo effect, but in most, it is indistinguishable from other factors such as spontaneous remission and regression to the mean. However, a significant number of studies, have also compared the placebo effect to the effects of receiving no treatment at all. For some conditions, this has been found to be a significant effect. For example, Ted Kaptchuk’s study on the use of open-label placebos in IBS, was found to improve symptoms by 60%, compared to just 30% without placebo. The American Medical Association highlights that “The use of placebo, when consistent with good medical care, is distinct from interventions that lack scientific foundation”.

Current medical guidelines for how to use of placebos in clinical practice

Few national medical associations have released official guidelines for placebo usage, however, the American Medical Association’s Principles of Medical Ethics outlines a set of criteria by which placebos can be integrated into medical practice. AMA state that “physicians may use placebos for diagnosis or treatment only if they:

  1. Enlist the patient’s cooperation. The physician should explain that it can be possible to achieve a better understanding of the medical condition by evaluating the effects of different medications, including the placebo.
  2. Obtain the patient’s general consent to administer a placebo. The physician does not need to identify precisely when the placebo will be administered. In this way, the physician respects the patient autonomy and fosters a trusting relationship, while the patient may still benefit from the placebo effect.
  3. Avoid giving a placebo merely to mollify a difficult patient. Giving a placebo for such reasons places the convenience of the physician above the welfare of the patient. Physicians can produce a placebo-like effect through the skillful use of reassurance and encouragement, thereby building respect and trust, promoting the patient-physician relationship, and improving health outcomes.” 

Whilst AMA is so far, the primary medical association to release official guidelines, various medical journals have published unofficial guidance in recent years. We outline them below:

British Medical Journal (BMJ)

An article by Lichtenberg suggested the following rules be used to assess justification for the use of placebos in clinical practice:

  1. The intentions of the physician must be benevolent: her only concern the wellbeing of the patient. No economical, professional, or emotional interest should interfere with her decision.
  2. The placebo, when offered, must be given in the spirit of assuaging the patient’s suffering, and not merely mollifying him, silencing him, or otherwise failing to address his distress.
  3. When proven ineffective the placebo should be immediately withdrawn. In these circumstances, not only is the placebo useless, but it also undermines the subsequent effectiveness of medication by undoing the patient’s conditioned response and expectation of being helped.
  4. The placebo cannot be given in place of another medication that the physician reasonably expects to be more effective. Administration of placebo should be considered when a patient is refractory to standard treatment, suffers from its side effects, or is in a situation where standard treatment does not exist.
  5. The physician should not hesitate to respond honestly when asked about the nature and anticipated effects of the placebo treatment he is offering.
  6. If the patient is helped by the placebo, discontinuing the placebo, in absence of a more effective treatment, would be unethical.

Psychotherapy and Psychosomatics

After the first Society for Interdisciplinary Placebo Studies (SIPS) conference, a team of placebo experts put together a list of recommendations about the use of placebos in clinical practice. These were published in a paper in 2018. The recommendations are as follows:


  1. Consider placebo effects as part of regular treatment
  2. Inform patients about placebo and nocebo effects in such a way that treatment effects are maximized and side effects are minimized
  3. Ensure a patient-clinician relationship that is characterized by trust, warmth and empathy in order to maximize placebo effects and minimize nocebo effects
  4. Train health-care providers in patient-clinician communication to maximize placebo effects and minimize nocebo effects
  5. Prefer open-label rather than hidden placebo prescription in those cases where there is evidence for efficacy and where prescribing a placebo is legal


  1. Do not take risks (e.g., prescribing invasive treatments) to maximize placebo effects
  2. Do not consider deception a necessary component of placebo effects

The gaps in the guidelines

The above guidelines are a great starting point to guide clinical use of the placebo effect. However, no guidelines yet refer to the conditioned placebo effect and specific ways in which the doctor-patient relationship can enhance the placebo effect component of other treatments.

The conditioned placebo effect

The conditioned placebo effect is a form of Pavlovian conditioning in which an active drug is given with a stimulus that then becomes the placebo. For example, a study by Benedetti et al. gave Parkinsonian patients daily injections of Apomorphine for 4 days. Following this, they gave them saline injections. The patients responded to the placebo as if it was the active drug for 48 hours. This demonstrates that there is potential for placebos to reduce the amount of active medication required. However, it is unlikely that this will be integrated into clinical practice, before studies into open-label placebo conditioning have been conducted.

The clinical interaction

Ted Kaptchuk states that the placebo is not just the medical intervention, but the whole “ritual of treatment”. This means that the placebo effect may be influenced by how the doctor communicates with the patient; the expectations of the treatment as discussed by the doctor; the longer-term doctor-patient relationship; the clinical setting and the appearance of the treatment. Clinicians do not have control over all of those factors, however, through their communication, they can influence the patient’s expectations and build a trusting positive relationship with the patient. The specifics of how this might be done are not yet clarified, leaving only two vague criteria in the Psychotherapy and Psychosomatics guidelines:

  • Ensure a patient-clinician relationship that is characterized by trust, warmth and empathy in order to maximize placebo effects and minimize nocebo effects
  • Train health-care providers in patient-clinician communication to maximize placebo effects and minimize nocebo effects

Further Reading

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