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Placebos contain no active ingredients and yet sometimes they make people feel better. How can that possibly happen and does it mean there is a place in medicine for 'dummy' treatments? And why are placebo treatments now included in clinical trials?

How would you feel if you found out your doctor had given you a placebo, in other words a "fake medication" that would not specifically treat your condition, but was a sugar pill designed to "keep you happy"?  Does it matter what the ingredients of the medications you were prescribed are, so long as you feel better after taking it?

Most doctors admit to having given placebos to patients, but is there anything wrong in that, if the patient feels better?

What are placebos?

Placebo means ‘I please’ and placebo treatments with no active ingredients, which are given purely to please, have been administered since time immemorial.  For most of that time it was believed that they fulfilled a need to maintain patients’ faith in medicine, when the doctor really had nothing he/she could – or wanted – to offer them.  (And before the modern medicines we have today became available, doctors often had very little to offer, other than placebos).

What form do placebos take?

Placebo treatments have been in use in all different forms through the ages. In older times they might have been what were called bread pills’, or bottles of colored water that looked potent.  In more modern times injections of water under the skin (IVs) and sugar pills have been given. Nowadays some might consider the prescribing of multivitamins or tonics, to be the modern equivalent of placebos ie something not intended to treat a specific condition.

Are placebo treatments completely useless?

For many years it was thought that the only benefit of placebos was psychological

In other words if you took something you believed was doing you good, your mind would tell you that you felt better. 

It was thought that the lower the person’s intelligence, the more likely they were to be influenced by placebo.  But in 1955 the first work was published which alleged that the effects were not all in the mind, but that placebos do actually bring about physical effects.  

This early work also put a figure on the level of susceptibility to placebo – finding that 35% (more than a third!) of people given placebo will feel some benefit from taking it.

This figure has been confirmed by more than one piece of research.

In modern clinical research there is also something known as the placebo ‘effect’, which applies equally to active as well as to ‘dummy’ medications. 

This is a beneficial effect which comes just from knowing that a treatment has being given. In other words, the power of suggestion is at work here; if you believe that you will feel better, it is likely that you will.

Placebo’s part in medical research

One of the greatest benefits of the placebo could arguably be in the development of medical research techniques.  When it was found that an inert substance could have benefits through the placebo effect, researchers realized that some of the benefit of active drugs could also be due to this effect, rather than solely to biological mechanisms.  This led to the development of controlled trials where patients are treated either with the active drug, or with a placebo, to establish how much greater the active drug’s effect is than that of the placebo

There is also an argument for including a no-treatment arm in trials, as it has been found that when they are, a difference is often seen between the no-treatment and placebo arms.

How can placebos have a beneficial effect?

Although the mechanism behind this is not fully understood, it is beyond doubt that there is a strong link between physical and mental states. Some people become physically ill when they are facing mental challenges such as stress, depression or grief.  Similarly there are phenomena such as ‘white coat hypertension’ where a person’s blood pressure will be higher when measured by a doctor or nurse in the clinic, than it is when measured away from a clinical setting. These are examples of the mind producing physical symptoms.  

It stands to reason that if a negative mental state can make you ill, or change physical characteristics, then positive thoughts can be just as likely to bring about therapeutic physical changes.

How could therapeutic changes be brought about?

The influence of mental state on physical conditions, in particular on pain, has been the subject of a lot of research.  It is known that when people feel happy, for example when engaged in a hobby or pastime, their pain is reduced or easier to bear.  This may be due to natural painkillers called endorphins, released from the brain when we are happy, and when exercising.  This is just one of the ways in which mental and physical states are connected. 

Is it ethical to give a patient a placebo?

The Hippocratic Oath, which doctors used to swear when they qualified, states ‘First, do no harm’, and negative effects have not been associated with placebo.

In theory a doctor should not give a placebo if he or she knows of an effective treatment for the patient’s condition, which does have actual active ingredients.

But clinical practice is not always that straight forward — as one of the cases below illustrates. Many also say that it is unethical to give a placebo without telling the patient it’s not active drug. And surprisingly, warning the patients in this way does not always ruin the placebo effect.

Is there a place in modern medicine for placebo?

Outside of clinical trials, placebos can be of benefit in modern medicine, when used appropriately.  An example is the case of a man with post-operative pain who was treated with injections of morphine.  He kept asking for extra injections, which, because of the serious side effects of morphine, the staff were unable to give him.  Instead they told him they could give him saline (salty water) injections, which have helped other people. 

The man accepted this and obtained pain relief from the injections  - despite knowing they were not morphine.  

Another case that demonstrates the power of the placebo effect even when we know that we're being given a placebo involved a woman with depression who demanded drug therapy after becoming very agitated during a hypnotherapy session. She was prescribed 25mg per day of a drug normally given at 200-300mg daily, and warned of this. The woman had immediate relief from her condition, avoided the side effects she might have experienced at higher doses and was able to carry on with other non-drug therapies. Despite the fact that she was still given active treatment, the dose was so low that any effects would have been a placebo.

Sources & Links

  • Kaptchuk TJ. Powerful placebo: the dark side of the randomised controlled trial. Lancet, 1998, 351, 1722-25
  • Lichtenberg P. The Role of the Placebo in Clinical Practice. Mcgill J Med. 2008, 11(2), 215–216
  • Lichtenberg P, Heresco-Levy U, Nitzan U. The ethics of the placebo in clinical practice. J Med Ethics 2004,30,551–554
  • www.ncbi.nlm.nih.gov/pmc/articles/PMC2582669/
  • www.ncbi.nlm.nih.gov/pmc/articles/PMC1733989/pdf/v030p00551.pdf

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