Saturday, 19 April 2014

The Placebo Effect - Mind Over Matter

Placebos are a medical phenomenon that can make us feel better, without any direct medical intervention. They were originally used as and referred to as “dummy pills”. However, recently more research has been carried out to investigate the mechanism behind how a placebo works – is there more to it that originally thought? Are the effects of a placebo all psychological? Or is there something actually happening in the brain? 

A recent BBC Horizon documentary (“The Power of the Placebo”) aimed to answer these questions, exploring different case studies where the use of a placebo has had surprising effects, to both researchers and volunteers. 

One study, conducted by Dr Chris Beedie, considered the effect of a placebo in pill form. In this study, cyclists were given a pill containing a new supplement that would supposedly enhance their performance. However, unbeknown to the cyclists, the supplement pills were actually just cornflour. To investigate, the cyclists first each had to complete one lap of the track. Before taking the pills, some of the volunteers noted that it was rare they would complete two laps of the track in one day (as the effort involved in each lap was so great), and so most were doubtful the supplement would make any difference. However, Dr Beedie found that more than half of the cyclists had improved their track times after taking them – some had even achieved new personal bests. The cyclists were also interviewed after the second lap, and some said they could feel a difference in their performance. This is amazing, considering the cyclists had only ingested cornflour! This study suggests that the effects of a placebo are psychological – if you believe you are taking something that will enhance your performance, you probably will. 

Another study was that of Professor Benedetti’s on high altitude performance. His study aimed to show whether placebo effects were psychological or could cause real changes in our bodies. To carry out his study, he split his group of volunteers into two groups. One group was given a canister of extra oxygen, and one a canister of fake oxygen. Both groups, however, were not informed of the nature of the experiment and believed the study was to see the effects of receiving extra oxygen at high altitude – in other words, the volunteers had no idea that some of them were to receive fake oxygen. By giving extra oxygen, this normally means that more oxygen would be delivered to muscles and so performance would improve. Professor Benedetti also looked at the level of PGE2 neurotransmitter during the experiment – high altitude levels cause blood oxygen levels to fall, and PGE2 to rise. This results in the common symptoms of altitude sickness. Astonishingly, the results found that those with the fake oxygen canisters showed no change in blood oxygen saturations, and actually showed a decrease in PGE2 levels. This decrease in PGE2 levels correlates with a lack of altitude sickness and maintained high blood oxygen levels, despite the harsh conditions. This study demonstrated that the placebo effect can cause real physiological changes in the body!  

A further study examined the body’s response to pain - with and without a placebo cream that supposedly would have analgesic effects. This study found, through use of brain scans, that use of the placebo cream resulted in endogenous opioid release in the periaqueductal area of the brain. This shows that the placebo effect taps into pain control areas of the brain in the same way as pain relieving drugs! This study gives a definitive answer to the question of whether placebo effects are imagined or follow real chemical mechanisms in the brain. 

A question raised consistently throughout the programme was whether there is a need to be duped in order to feel the effects of a placebo. A study conducted on volunteers suffering from IBS tried to prove that there was no need. 80 volunteers were told they would be receiving a placebo pill, and surprisingly, at the end of the trial 62% found they had improved symptoms. One volunteer speculated as to whether it was her “wishing for a cure” that helped alleviate the symptoms. 

As demonstrated from the studies above, some results are conflicting as to the mechanism by which a placebo works. Another question raised by researchers was whether some people may have a genetic disposition towards a positive response to a placebo. However, placebo research is still in its infancy, and no doubt further research may provide answers to questions surrounding the topic. 

If you are interested, below is a link to the documentary. I highly recommend it!


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