Did you know that placebo effects and nocebo effect can be evoked without a placebo; or that some people may be genetically predisposed to placebo response? In a talk by Dr Luana Colloca we learn about the conflicts, ethics and future use of the placebo effect in clinical practice. Here, we summarise some of the key ideas in Dr Colloca’s talk.

Dr Luana Colloca’s talk is available here: https://chapelboro.com/category/wchl/weekend-shows/your-health @ 8:35-33:10


There is a great conflict of perspectives when it comes to the placebo effect. Nowhere is this clearer than in the realms of clinical trials and clinical practice. In clinical trials, there is a desire to minimise the placebo effect, to demonstrate the greatest possible benefits of a new treatment. On the other hand, in clinical practice, doctors want their patients to have the best response to treatment. So the more the placebo effect is maximised, the better the outcome for the patient.

Placebo Responders

Some people respond to the placebo effect more strongly than others. The reasons for this are not completely understood, but there may be a genetic difference that allows some people “to activate, what we call, the endogenous pharmacy” – the beneficial chemicals within your own body. If we understand the basis of these differences in placebo responses, we may be able to personalise treatment. We could “tailor the administration of a painkiller to the individual patient’s needs”.

The Unspoken Ethics Code

The fact is that even with modern medicine, physicians still prescribe placebos to patients. It may not always be sugar pills and saline injections, but sometimes it’s impure placebos, such as antibiotics for a viral infection. The treatment prescribed should not have any pharmacological effects upon the condition, but a doctor prescribes it anyway, “to benefit a patient”. (Read our article on the subject here: The Secret Prescription)

Many doctors would prefer to use placebos open-label, where the patient knows that they are being offered a placebo, but they also know why. It is up to the doctor to explain to their patients that their symptoms are related to functions that depend upon the brain and to let them know that there are placebos mechanisms that they could use to help resolve those symptoms.

As mentioned above, doctors are prescribing placebos, but there is an unspoken ethics code around their use. Some situations can warrant using placebos, some situations, such as pain, respond better to placebos than others. Placebos should not be prescribed for life threatening situations and serious problems. But there is a balance to be found “cancer can’t be cured by placebos, but you can treat the fatigue, you can treat the pain”.

Interestingly, you “can evoke placebo effects without any placebo”. Placebo effects result from the whole ritual of a treatment: communication can have a noticeable effect upon patient outcome.

The Nocebo Effect

So, if the ritual of treatment can have positive effects, doctors also need to be wary of the negative effects – the nocebo effect. “The way a situation is communicated to a patient can be detrimental”, causing a nocebo effect. Doctors need to pay attention to the way they inform a patient about negative outcomes, expected side effects etc. “Words do matter and contribute to potentially biologic changes”. Doctors need to know that what they say and how they say it could affect the patient outcome.

Next Steps

  1. “Continue with the genetic approach” to identify placebo responders. This will allow us to “optimise the therapeutic management of symptoms”.
  2. “Understand how nocebo effects can impact clinical outcomes”
  3. “To educate future clinicians about the neurobiological impact of communication, especially when it comes to negative expectations and the nocebo effect.
  4. “Create a bridge between laboratory research and clinical trials” so that the knowledge of the placebo effect can inform the future design of clinical trials and help drug development.

More from Dr Luana Colloca:

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