Placebo effect update

For years, the placebo effect has baffled doctors and scientists. People taking inactive medications really do get better to a certain extent and there has been much questioning as to why this happens and exactly what triggers the power of the placebo.

Placebos are used in virtually all clinical research. New medications are tested against inactive ones to ensure the medicine is truly helping people get better. Study volunteers do not know whether they are receiving the fake medicine or the real one and in order for the new drug to be deemed effective, it has to be shown to work better than the placebo.

Although it may seem as though the group taking the real medicine would stick out very obviously from those taking the fake drug, many people do experience significant improvement just taking the placebo.

Until fairly recently, this was deemed to be almost entirely a psychological effect. When we believe we are getting better, our body tricks us into feeling a bit better.

Some research over the past couple of years has finally quantified a mind-body connection showing our physiology does indeed react to placebo.

Most recently, a study of Parkinson's Disease patients completed out of UBC found the placebo effect was maximized when study volunteers were told they had a good chance of getting the real treatment instead of a sugar pill but were still kept somewhat unsure.

In this study of placebo, all volunteers received inactive medication. Equal numbers were told they had a 25, 50, 75 or 100 percent chance of getting real medicine. Those who were told they had a 75 percent chance of getting the active drugs experienced the most significant improvement.

It seems the hope of real treatment coupled with uncertainty stimulated the brain's reward system and their brains produced significant amounts of dopamine, a chemical key to reward that is also lacking in the brains of Parkinson's sufferers.

No dopamine response occurred in those given placebo after being told they had only a 25 or 50 percent response and interestingly, no response occurred for those told they had a 100 percent chance of real medicine either.

These findings showed that a person's expectations directly regulate the power of the placebo by stimulating the brain's reaction.

More research into different conditions including chronic pain, depression and others are needed to see whether this effect would be the same. In Parkinson's disease, the brain's reward system is abnormal, so there are questions remaining about whether some response might happen at lower expectations in those with normal reward systems.

This study is somewhat similar to another one completed in the US a couple of years ago where healthy volunteers were given painful stimuli and told they were receiving medicine to ease their pain.

In this case, the volunteers' brains released endorphins to block pain receptors when they were told they were receiving medication.

Although it is interesting and valuable to learn how the placebo response works as it may be a useful tool to augment effective treatment, it is dangerous to assume replacing active medication with placebo would yield long term results. In cases of serious, chronic or life-threatening illness, the person may feel better but still die sooner if not using an effective treatment.

Generally, placebo effect does not last indefinitely. In psychiatry placebo effects are generally short-lived and do not eliminate all symptoms or lead to lasting improvement in a person's ability to function.

 

Current Studies

 Alzheimer's Disease 

 Parkinson's Disease

 

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