Power of the Placebo

by Dr. Reeja Tharu on  September 10, 2008 at 3:17 PM Health In Focus
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What do powdered mummies, mandrake root, spider webs, ants, scorpions, worms, combs, bones, teeth, viper's flesh, crab's eyes, and pearls have in common with sugar pills and saline? They are all equipped 'to please'- They are placebos!

Acoording to Hooper's Medical Dictionary, Placebo is "an epithet given to any medicine adapted more to please than benefit the patient". It is an inert substance or drug or formulation that is administered to a patient who believes in its potential to cure.

Since the early 20th century, the miraculous powers of the placebo,known as placebo effect, has been observed. This effect is brought about by the patient believing in the therapeutic potential of the administered substance, irrespective of its potency.

The belief of the patient goes hand in hand with suggestions from a person of authority or with information that the patient percieves as reliable. The placebo effect becomes evident when a patient's symptoms are alleviated  after the administration of the placebo.

The nocebo effect (latin meaning 'I will harm')  is the other side of the same coin. Here the patient's symptoms worsen when the placebo is administered.

The psychosocial aspect to medical treatment demands that  the patient has implicit faith in the given therapy.The placebo effect is a testimony to the positive response of the human mind to a therapeutic approach.

The common practice of prescribing antibiotics to treat influenza and cold  is a pointer to the use of placebos in modern medicine.

Most of the drug trials that are undertaken for a condtion compare the efficacy of a new drug with either an already available  proven drug or a placebo where no such drug is available.  If the drug trial  beats the placebo effect by a stastical margin, it is accepted for treatment. In case of benign conditons there are not much  ethical dilemmnas if a patient's gives a proper informed consent, however in case of life threatening condtions or cancers the use of placebo is ethically questionable.      

Doctor -Patient relationship

The word 'placebo' has several meanings. But when used in the patient -doctor context it means,in Latin, 'I will please'. Placebos are an integral part of doctor -patient relationship. Restoring the patient to normal health and boosting their morale is considered as the prime task at hand by many doctors.

Thus, when a well-intending doctor prescribes a placebo he actually means "I shall gratify the patient's request for a medicine or a drug which I cannot/will not supply, by giving him an ineffective drug, in the pretext that it is effective".

The most common placebos prescribed are vitamins, for complaints of fatigue, and antibiotics, for viral infections.Sugar pills and syrups are not uncommon.

An Australian doctor coined the word 'Obecalp' ('placebo' spelled backwards) in 1998, in order to mask the word 'placebo' and make  it less decipherable  to the patient.

Pleasing through Placebos
Placebos can be very effective in treating specific cases .For instance, burns patients with respiratory distress cannot be administered opoids, like morphine, or opioid derivatives such as pethidine because these medicines will aggravate the respiratory distress.This is when a normal saline injection will  help tremendously  by relieving pain in these burns patients who are convinced that they are being given a pain killer.

It has been observed that  the placebo effect is mostly subjective. In most of these situations it is noted that, if anxiety is relieved  the patient will natuarally feel better.

Some of these conditions include psychiatric conditons like mood disorders, indigestion, irritable  bowel syndrome, asthma, allergies, headache, irritable bladder and impotence due to performance anxiety. Here the placebo affect can be as much as 30 to 35%. Sometimes researching a drug that is better than the 'dummy placebo pill' may involve expenditure of millions of dollars for a drug company.  

PlaceboEffect - Mechanism


Strong scientific evidence,through brain imagery studies, indicates that  the placebo effect is a complex psychobiological phenomenon involving biological substrates, unique brain processes, and neurological reactions.  

For the placebo to have total effect,it is important for the patient to know that a  'drug' is being administered.The mechanism behind the placebo effect can be explained with the help of three theories.

a) Expectancy Theory - According to this theory there is a conscious or an unconscious effort by the patient to influence the reporting regarding the outcome .

"Expectation is a powerful thing," says Robert De Lap, M.D. "The more you believe you're going to benefit from a treatment, the more likely it is that you will experience a benefit." 

b) Conditioning- It is a type of associative learning whereby the patient learns to link a stimulus with a certain response. Here the stimulant is the placebo and the response is the relief  that the patient experiences .  

c) Motivation-This hypothesis is based on the fact thatthe placebo effect takes place due to the patient's motivation or desire to get better and to co-operate with the doctor.  

The Murky side


Some critics associate placebos with deceptivity, and contend that it may harm the doctor-patient relationship in the long run. Some of the other negative effects include the following-

  • An average estimate says that only 30% of  patients respond to placebos
  • It has been pointed out that placebos can interfere with the correct diagnosis and treatment of grave illnesses
  • The effect of placebos wears off with time making it useless for long- term use.
  • Prescribing placebos could cost doctors'their reputation.They could be charged with fraud if the patient gets suspiscious about the 'drug' administred.
  • Using placebos to treat cancer patients is a great risk, as they simply do not have the time to wait.

Placebo-Salient features

  • Placebos do not have the pharmacodynamics to cure; however, a patient may either get relief from symptoms or may experience worsening of the same  after taking a placebo.
  • If a placebo is given to mimic a  drug previously administered, it is possible that it brings about the effects of the original  drug.These effects are the physical response to  a psychological triggering(pavlov effect)  .
  • Many illnesses are completely resistant to the effect of placebos .
  • Placebo administration involving ingestion, injection, or incision is often more powerful than a non-invasive technique.
  • The placebo effect is more evident in diseases whose outcome can be analyzed subjectively ; it does not impact illnesses that are objectively evaluated
  • It has been observed that patients who were administered placebos experienced withdrawal symptoms similar to those experienced by people who were given real drugs.
  • The effect of the placebo multiplies when it is administered by a figure of authority.
Contrary to its popular association with the quacks, 'the placebo effect' is a fast-emerging area of research, with immense clinical implications. This research will, hopefully, help in the understanding of this common 'therapeutic' ingredient. A consensus, regarding   the usage of placebos in contemporary medicine, needs to be arrived at.

Source: Medindia

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