The concept of the placebo is pivotal in modern medicine. It helps to differentiate the “true” effects of medical intervention, typically pharmacological treatment, from the psychological biases that a patient may conjure in their mind while receiving treatments. Yet, oftentimes we see that its mere concept is sufficient to produce results - let's take a look at why this is so.

The placebo effect leads to symptom improvements

Traditionally, the placebo effect is seen as a false sense of wellbeing or, alternatively, physical deterioration that arises from inert substances that constitute a placebo pill. However, this concept presents an over-simplistic view of the complex machinery of the human mind, meaning it is not entirely accurate.

Professor Ted Kaptchuk from Harvard Medical School has provided a much comprehensive explanation of the placebo effect - he pointed out in his writing that placebo effects are “symptom improvements” experienced by patients due to their “participation in the therapeutic encounter, with its rituals, symbols, and interactions.” (1)

It is common to encounter placebo effects during clinical practices. Many patients will claim their condition has become better even though other more objective assessments (such as a laboratory test results) suggest otherwise. Many of these placebo effects only alter symptomatic manifestations of a disease and do not affect the underlying pathophysiology of the condition.

Effect is produced via a complex neurobiological pathway

Often times, the placebo effect is produced via a complex neurobiological pathway. In his writing, Professor Kaptchuk explained that the activation of specific parts of our brain via common neurotransmitters such as endorphins, cannabinoids and dopamine are responsible for producing the sense of well-being in patients. In addition, recent studies into placebo effects discovered genuine biopsychosocial phenomena that provided a solid foundation to support the credibility of placebo effects. (1)

There are many observable examples of the placebo effect. For people who suffer from seasonal allergic reactions (e.g. hay fever), an image of pollen may precipitate an allergic reaction. Similarly, if patients were to be told to ingest a stimulant, their blood pressure and heart rate may subsequently increase even if the pill is actually a placebo. There is an intimate link between what patients expect from the treatment and the actual physiological experience.

The nocebo effect

The placebo effect is not only limited to positive experiences, but also include adverse reactions, as seen in many instances. This is known as the nocebo effect. It denotes the condition where a person suffers more symptoms of the underlying disease or increased side effects after taking the placebo pill. A good example of the nocebo effect is the heightened sense of pain that arise from mere expectation of such a sensation, or an amplified awareness of existing background discomforts (1,2).

Although many regard the placebo effect as a mere arbitrary psychological response towards treatment, recent progress in placebo studies have opened up new possibilities of utilising this effect to enhance treatment. At the current stage, scientists still do not fully understand the phenomenon. Specifically, these include when and how placebo effects occur, its temporal sequences and how to reliably elicit a placebo response to enhance treatment quality.

Adapt to the unique circumstances at hand

The placebo effect has always been an element that is strictly controlled in clinical trials but rarely explored for its therapeutic efficiency. Moreover, the ethical questions of using placebos in both the research setting and in clinical practice have been greatly debated, but less well concluded, among scholars (3,4). It is imperative for us to acknowledge that currently there is no straightforward solution but to adapt according to each unique circumstance if we were to harness the placebo effects for better treatment. MIMS

Read more:
When are placebos no longer placebos?
Expectations drive the Placebo effect to work
Acupuncture claims: worth a try or just a placebo?

1. Kaptchuk TJ, Miller FG. Placebo Effects in Medicine. N Engl J Med. 2015 Jul 2;373(1):8–9.
2. American Cancer Society. Placebo Effect [Internet]. 2015 [cited 2016 Nov 21]. Available from:
3. Stang A, Hense H-W, Jöckel K-H, Turner EH, Tramèr MR. Is It Always Unethical to Use a Placebo in a Clinical Trial? PLoS Med. 2005 Mar 29;2(3):e72.
4. Lichtenberg P. The ethics of the placebo in clinical practice. J Med Ethics. 2004 Dec 1;30(6):551–4.