Open-label placebos and the power of expectation

Open-label placebos and the power of expectation: Why the honest sugar pill works

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eine tablette auf einem kleinen teller, im hintergrund liegt eine zeitschrift

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The placebo effect demonstrates how expectations shape the perceived effects of medication. Why even a placebo that is openly declared to be inactive helps, why the nocebo effect is more powerful, and what this means for every treatment.

Open-label placebos and the power of expectation: Why the honest sugar pill works

It is often claimed that a placebo only works as long as the patient believes in the medicine. Recent research contradicts this: even a placebo openly declared to be inactive alleviates symptoms.

What it’s all about:

· the placebo effect

· the power of expectation

· Why the nocebo effect is even stronger, and

· What both reveal about any medical treatment.

What is an open-label placebo?

In traditional placebo research, deception is part of the design: the patient is given a tablet containing no active ingredient and believes it to be a medicine. The open-label placebo dispenses with this deception. The doctor explicitly states: ‘This capsule contains no active ingredient, only cellulose or sugar, and studies show that it can still help with your symptoms.’ The patient then takes it, knowing full well what it is.

The impetus came in 2010 from a study by placebo researcher Ted Kaptchuk at Harvard Medical School. Patients with irritable bowel syndrome were given openly labelled placebo capsules or no treatment for three weeks. The placebo group reported significantly greater relief, even though the label stated ‘placebo’. What initially seemed like a curiosity has since been extensively tested.

A systematic review with meta-analysis summarised clinical trials on open-label placebos and found a moderate-to-large effect across a range of conditions (standardised mean difference of 0.72). Conditions studied included back pain, cancer-related fatigue, ADHD, allergic rhinitis, depression, irritable bowel syndrome and hot flushes. In June 2026, the specialist journal *The Lancet Psychiatry* devoted a separate article to placebo research, which re-evaluates the field.

What is the placebo effect, and what is the power of expectation?

The placebo effect refers to the improvement in symptoms following treatment without an active ingredient. It is never the tablet alone that has the effect. Every time a medicine is taken, it involves a combination of substance, expectation, ritual and relationship. In an open-label placebo trial, the active substance is omitted, but the rest remains, and this ‘rest’ has measurable physiological effects.

Expectation is the strongest active factor in this bundle. Those who enter treatment, convinced it will help, actually experience fewer symptoms; those who are sceptical or anxious experience less relief. This power of expectation explains an old clinical observation: why do many conditions improve after the very first appointment, before an active ingredient has even had a chance to take effect? The expectations with which a person enters treatment have an effect in their own right.

This brings into focus a factor long regarded as a mere ‘soft’ accessory. The patient’s expectation is a biologically rooted factor, one that is measurably different from zero in clinical trials and can be utilised clinically.

How can a medicine without an active ingredient have an effect?

The first mechanism is expectation itself. It has been shown to alter the release of the body’s own neurotransmitters: endogenous opioids and dopamine are released, pain processing in the central nervous system is modulated, and autonomic functions such as heart rate and digestion are influenced. The neurobiological basis of these processes has been largely elucidated over the last two decades.

The second mechanism is conditioning. Anyone who has, over the years, found that swallowing a tablet is followed by an improvement has developed a learned physical response. The stimulus ‘taking a tablet’ triggers this response even when the active ingredient is absent, much like Pavlov’s dog reacting to the bell. This response is a conditioned reflex of the organism and has little to do with imagination.

The third mechanism is the significance of the treatment situation. A person who is suffering receives attention, a diagnosis, a ritual and the message that someone cares. The body responds to this significance. The open-label placebo study shows that the response persists even when all parties involved have laid their cards on the table.

What mechanisms distinguish the placebo effect from spontaneous recovery?

A common objection is that placebo effects are merely natural fluctuations: symptoms fluctuate, and anyone who seeks treatment when their condition is at its worst will almost inevitably feel better afterwards. This objection must be taken seriously. Regression to the mean accounts for part of the improvement observed in every group. That is why good clinical trials compare results with an untreated control group that follows the same natural course.

The difference remains. In the irritable bowel syndrome study and subsequent research, the groups receiving a placebo fared better than the untreated groups with identical baseline conditions. This difference is the actual placebo effect: the proportion of improvement attributable to expectation, conditioning and ritual.

The limitation remains important. Placebos alleviate subjective symptoms with a strong central nervous system component: pain, fatigue, nausea, anxiety and depressive mood. They do not cure a disease, shrink a tumour, lower insulin levels or replace an antibiotic. Their domain is the patient’s experience; yet it is precisely there that they are clinically significant, because that is where the suffering lies that brings patients to the surgery.

Why is the nocebo effect more potent, and what does the patient information leaflet say?

The nocebo effect is the dark side of expectation: negative expectations generate or exacerbate symptoms. Anyone who reads in the package leaflet that nausea may occur is more likely to experience it. An experimental study from 2025 directly compared the two effects and found that the nocebo effect was stronger and lasted longer than the placebo effect.

From an evolutionary perspective, this asymmetry makes sense. An organism that reacts strongly and persistently to danger signals is more likely to survive than one that gives equal weight to safety signals. For medicine, this means that words warning of harm are more effective than words promising improvement – an uncomfortable realisation when information is provided about a possible side effect.

In practice, this comes into play with package leaflets and when discontinuing medication. Some of the reported withdrawal symptoms from antidepressants are considered to be expectation-driven: those who expect withdrawal symptoms are more likely to notice physical signals and interpret them as withdrawal. An ongoing programme of studies is therefore investigating whether open-label placebos can help with the gradual tapering off of antidepressants. This would mean that expectations would work specifically in the patient’s favour rather than against them.

Is treatment with placebos ethically justifiable?

The covert placebo – where the doctor prescribes sugar and calls it medicine – breaches the duty of disclosure and undermines the trust on which all treatment rests. It has no legitimate place in modern medicine. Surveys show, however, that concealed placebos are quite widespread: vitamins for fatigue, antibiotics for viral infections, homoeopathic remedies – prescriptions whose expected effect lies primarily in the ritual.

Treatment with placebos in an open form resolves this dilemma. It requires no deception; informing the patient is part of the mechanism of action. The patient knows what they are taking and makes an informed decision. This makes it possible to use the placebo effect honestly – as a complement to standard treatment, as an option for symptoms that do not respond well to medication, or as support for reducing medication.

The question of attitude remains open. A placebo handed out with a shrug is unlikely to achieve much. Clinical trials operate within a carefully structured framework: the practitioner explains the current state of research, takes the patient’s suffering seriously and links the administration of the placebo to a plausible model. The effect arises from this relationship, which also explains why it cannot be scaled at will.

What does the power of expectation mean for doctors and psychotherapy?

Placebo research is research into words. It shows that the way a diagnosis is phrased, a prognosis given and a side effect announced have physiological consequences. ‘You’ll just have to live with it’ is a nocebo intervention. ‘Most people with this diagnosis cope well, and we have several options’ is a positive expectation, both statements relating to the same diagnosis. With every sentence, doctors shape the patient’s expectations.

This is familiar territory for psychotherapy. Expectation, hope and the quality of the therapeutic relationship are among the best-documented factors influencing outcomes across all schools of therapy. Placebo research provides the experimental basis for this. It demonstrates in the laboratory what psychotherapy utilises in practice: that the framework within which help is provided is itself an active agent.

At the same time, this research guards against esotericism. Anyone who understands that expectation shapes physiology needs no quantum field to explain improvement following a healing ritual. The wellness industry sells the placebo effect daily under a thousand different names and with substantial profit margins. The honest alternative identifies the mechanism, utilises it transparently and dispenses with the metaphysical superstructure.

Can positive expectation be utilised in everyday life?

Yes, and without a single sugar pill. The first starting point is how we manage our own medication. Anyone who takes an effective medication with inner reluctance and an expectation of disaster is working pharmacologically against themselves. Anyone who combines taking the medication with a fixed ritual, an understanding of how it works, and realistic confidence gains the additional benefit of the effect's expectation component. A positive attitude does not replace medication, but it does enhance its effect.

The second point of focus is self-care rituals. An evening cup of tea, a walk after a meal, breathing exercises before bed – such routines have an effect beyond their immediate physiological impact, acting as conditioned signals of safety. This explains why personally meaningful rituals often work better than objectively equivalent measures that lack personal significance.

The third approach concerns the language we use with others. Parents have always reassured children with rituals whose active ingredient is affection. Those who support loved ones through an illness help shape their expectations through the stories they tell and the questions they ask. Placebo research recognises the value of this everyday care: its effect can be measured.

What are the limits of placebo research?

The body of research on open-label placebos is promising but still in its infancy. Many clinical trials are small, short-term and unblinded. Participants naturally know which group they are in. It is difficult to distinguish between the effects of expectation on subjective reports and genuine changes in symptoms – a problem that researchers are addressing by using objective measures and longer trial durations.

Added to this is the question of generalisability. Those who take part in a placebo trial are open to the concept. It is unclear whether the effect would be the same in sceptical patients in everyday clinical practice. Furthermore, efficacy varies considerably depending on the clinical presentation and on the presence of chronic conditions. It is fair to say that open-label placebos are a serious option for subjective symptoms, but they are neither a miracle cure nor a substitute for effective treatments.

It is precisely this level-headedness that strengthens the findings. There is no need for exaggeration to state what placebo research shows: the body responds to meaning, and it does so even when told the truth.

Key points in brief

• Open-label placebos are administered without deception: the patient knows that the capsule contains no active ingredient, and yet their symptoms improve measurably.

• A meta-analysis of clinical trials found a moderate to large placebo effect (SMD 0.72) for back pain, irritable bowel syndrome, fatigue, allergic rhinitis and depressive symptoms.

• The mechanisms involved are expectation, conditioning and the significance of the treatment ritual. These have demonstrable physiological effects (endogenous opioids, dopamine, altered pain processing in the central nervous system).

• The nocebo effect – symptoms caused by negative expectations – is stronger and more persistent than the placebo effect. This explains some of the withdrawal symptoms associated with antidepressants and the impact of certain information in the patient information leaflet.

• Placebos alleviate subjective symptoms. They do not cure any illness and are no substitute for effective treatment.

• For clinical practice and therapy, this means: words, the context in which treatment is framed, and the patient’s expectations are all part of the treatment, and the power of expectation needs no esoteric explanation.