What is a Placebo?

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What is a Placebo?

Many of you might have heard the term 'placebo' at some point. When it comes to clinical trials, this term is quite frequently been used. But, what actually a placebo is? Why is it being used in the clinical trials? What is its importance in clinical trials? Continue reading to know all these ...

Defining Placebo:

In a clinical trial, a placebo can be defined as medically inactive drug which is often referred by the term 'sugar pill'. In clinical research, placebo will be administered to the subjects as control treatments which will depend on the usage of measured suggestions. Some of the commonly used placebos are:

- Inert tablets

- Vehicle infusions

- Sham surgery

- Other procedures

At times, placebo might also have a positive effect on the participant's subjective experience if he/she knows that the given treatment does not include any active drug candidates when compared with the control group participants who knowingly did not receive a placebo. (1), (2)

Under this definition of placebo, a wide range of substances can be placebos exhibiting the placebo effect. Some examples are:

Pharmacological Substances:

- Pills

- Creams

- Inhalants

- Injections

Medical Devices:

- Ultrasound

Sham Surgery:

- Sham electrodes

- Sham acupuncture

Bedding not treated for reducing allergies

Physician (1)

What is Placebo Effect?

Sometimes the subjects who are given a placebo treatment will have an improvement in medical conditions and this phenomenon of an individual's symptoms improving when they have been given only a dummy treatment is called the placebo effect. This effect is a mysterious yet fascinating effect that could be powerful. It is to be noted that the placebos are powerful particularly in conditions where symptoms are important. (3)

At present, the placebo effect is a subject of recent scientific researches that are aiming to understand the underlying mechanism of actions on the following conditions:

- Pain relief

- Immunosuppression

- Parkinson disease

- Depression

And, the placebo effects point to the significance of perception along with the brain's role in our physical health. This effect is sometimes being referred to as the physiological effect since the placebos are inactive substances that do not cause anything directly. For these reasons, Moerman and Jonas have introduced another term 'meaning response' which means that the brain is associating with placebo and causes the physiological placebo effect. (1)

Clinical Trials and the Placebo Effect:

The dummy treatments are being provided to the participants in some clinical trials. A placebo drug would look same as the drug under investigation and hence, you would not know which one you intake. Some of the subjects might even feel better after consuming placebo drug as they think they are being administered with the real medicines. This is called the placebo effect in clinical trials. (3)

What are Placebo-Controlled Studies?

These studies are the way of testing a medical treatment in which a control group would receive a placebo treatment in addition to a group of participants that receive the treatment to be investigated. The primary purpose of the placebo group will be to account for the placebo effect which is the effect from the treatment that does not depend on the treatment itself. The factors included are:

- Knowing one is receiving the treatment

- Attention from health care professionals

- Expectations of the effectiveness of the treatment by those conducting the clinical trial

It is to be noted that without any placebo group to compare, it will not be possible to know whether the investigative treatment had any effect. It is due to this reason the use of placebos has become the standard control component in most of the clinical trials that attempt to perform some quantitative assessments of the efficacy of medicinal treatments or drugs. (4)

Basic Setup of Placebo-Controlled Studies:

The basic of setup of placebo-controlled studies would involve two different groups of participants:

- One group that receives the investigational drug

- One group that receives a placebo

Most times, these types of clinical trials will be double-blinded which means that both the trial participants as well as the researchers involved in the study do not know which group is administered with the experimental drug. A major reason for blinding the clinical trial is to avoid any bias. (5)

How the Success of a Drug Determined in Placebo-Controlled Studies?

In a placebo-controlled study, if more numbers of trial subjects report significantly better outcomes with the investigational drug than with the placebos, then the experimental drug will be considered a success given the condition that it also meets all other criteria such as safety concerns. (5)

Prescribing a Placebo:

Although for ages doctors have been prescribing placebo, they have not been talked much. Various studies and surveys that have been conducted during the recent times have shown that the doctors prescribe placebos when they do not have any other form of relief to offer the patient may it be because there is no effective medicine available for the particular medical condition or because the patient could not take commonly prescribed medications due to the reasons like side effects.

One other situation where the doctor will prescribe placebo is when a patient insists on taking some particular medications. One of the common examples for this case will be the prescription of antibiotics when an individual has cold or other illnesses that are being caused by viruses.

Commonly Prescribed Placebos:

When a doctor is prescribing a placebo, it is not usually the sugar pill. As per the surveys that were conducted during recent times, the most commonly prescribed placebos were the pain pills like:

- Aspirin

- Vitamins

- Antibiotics

- Sedatives (5)

Approval of Placebo-Controlled Trials:

For the approval of placebo-controlled trials, the following questions need to be considered:

- Do subjects have a medical condition for which treatment is available?

- Will the lack of treatment likely lead to the disease progress during the trial?

- If the disease progresses, is this can be reversed?

- How far will be the burden of disease progression?

- Is there any substantial evidence that the investigational treatment is of therapeutic value?


(1) http://en.wikipedia.org/wiki/Placebo

(2) http://www.cancer.net/navigating-cancer-care/how-cancer-treated/clinical-trials/placebos-cancer-clinical-trials

(3) http://www.nhs.uk/conditions/clinical-trials/pages/fairtests.aspx

(4) http://en.wikipedia.org/wiki/Placebo-controlled_study

(5) http://science.howstuffworks.com/life/placebo-effect2.htm

(6) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1070847/

About the Author

Tharani Rajamanickam's picture

I am Tharani. I have Bachelors degree in Biotechnology. I am passionate about the healthcare and medical industry and continue to explore, learn and share and I bring in a wealth of knowledge and expertise to help you keep updated with current trends and developments. I have gained a lot of experience in clinical field by working in clinical trials arena. Stay tuned..

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