A study in the journal PLoS ONE suggests that some people responding to treatments that have no active ingredients in them may be down to their genes.
The so-called “placebo effect” was examined in 104 patients with irritable bowel syndrome (IBS) in the US.
Those with a particular version of the COMT gene saw an improvement in their health after placebo acupuncture.
The scientists warn that while they hope their findings will be seen in other conditions, more work is needed.
Edzard Ernst, a professor of complementary medicine at the University of Exeter, said: “This is a fascinating but very preliminary result.
“It could solve the age-old question of why some individuals respond to placebo, while others do not.
“And if so, it could impact importantly on clinical practice.
“But we should be cautious – the study was small, we need independent replications, and we need to know whether the phenomenon applies just to IBS or to all diseases.”
The placebo effect is when a patient experiences an improvement in their condition while undergoing an inert treatment such as taking a sugar pill or, in this case, placebo acupuncture, where the patient believes they are receiving acupuncture but a sham device prevents the needles going into their body.
Two groups in the study had this type of treatment. One group received it in a business-like clinical manner and the other from a warm supportive practitioner. A third randomly chosen group received no treatment at all.
After three weeks the patients were asked if they had seen an improvement in their IBS, a common gastrointestinal disease that can cause abdominal pain and discomfort.
The team then used blood samples to look at what variant the individual had of the catechol-O-methyltranferase (COMT) gene. This plays a role in the dopamine pathway, a chemical known to produce a feel-good state.
Paper author Dr. Kathryn Hall, from the Beth Israel Deaconess Medical Center (BIDMC), said this gene had been chosen because “there has been increasing evidence that the neurotransmitter dopamine is activated when people anticipate and respond to placebos”.
The researchers found individuals with a COMT variant that triples the amount of dopamine in the front of the brain felt no improvement without treatment but an improvement with the placebo acupuncture.
Ted Kaptchuk, director of the Program in Placebo Studies and Therapeutic Encounter at BIDMC, said: “We wanted to tease apart the different doses of placebo.
“We got an effect in individuals with this specific genetic signature for the general placebo, but an even bigger effect in the elaborate placebo where warmer care was given.
“You can really see the advantage of a positive doctor-patient relationship.”
Fabrizio Benedetti, professor of neurophysiology at the University of Turin Medical School, Italy, warned that dopamine may not be the only chemical involved with the placebo effect.
“A previous study on the genetics of placebo in social anxiety disorder showed that it is serotonin that is associated to placebo responsiveness and not dopamine,” he said.
“While this is a very interesting work, what we have learned in the past few years is that there is not a single placebo response and a single mechanism, but many, across different medical conditions and therapeutic interventions.”
Italian striker Mario Balotelli was sporting three tramlines of blue sticky tape on his back in the Euro 2012 Championship.
And at Wimbledon, Serbian tennis player Novak Djokovic has had his elbow patched up with the same stuff.
So what’s behind this latest sporting fad?
The Japanese makers of Kinesio tape say it gives players an edge by mending injuries.
Although it might seem like a new idea, the tape has been around since the 1970s.
The brainchild behind the tape, Dr. Kenzo Kase, says he came up with the design because he found standard taping techniques, like conventional strapping, too restrictive for his patients.
Although standard strapping provides muscle and joint support, it limits movement and, according to Dr. Kenzo Kase, gets in the way of the healing process by restricting the flow of inflammatory fluids below the skin.
The Japanese makers of Kinesio tape say it gives players an edge by mending injuries
Kinesio tape is different, he says, because it lifts the skin to assist this lymphatic flow, which, in turn, reduces pain and swelling.
However, Dr. Kenzo Kase admits there have been too few studies to prove these scientific claims.
Dr. Kenzo Kase says people have been using his tape with success for more than 30 years. But he recognizes that only solid scientific evidence can silence critics.
“We have many people researching but the society of Kinesio taping therapy itself – the International Kinesio Taping Association – is only five years old. We need more evidence. We do not have research reports. Part of the reason people are using Kinesio tape is to find the science.”
Another element to consider is the power of persuasion or “placebo effect” – if you believe something will work then you will see results.
John Brewer, a sports professor at the University of Bedfordshire, said: “Personally, I think it is more of a placebo effect. There is no firm scientific data to show that it has an impact on performance or prevents injuries.
“My concern is that there is little that you can put on the skin that will have a real benefit for the muscles that lie deep beneath.
“The power and stress going through the joints is immense.
“But, saying that, I can’t see it would cause any real problem, other than making you lose a few hairs.”
In theory, anything that can lessen the oscillations or vibrations that go through the muscle when you are doing intense sport will be beneficial, he said.
Phil Newton, a physiotherapist at Lilleshall, one of the UK’s National Sports Centres, said: “It’s a multimillion-pound business, yet there’s no evidence for it. There’s a whole host of companies making this tape now.
“A lot of medical practitioners do use it.
“It is different to the various types of tape that physios have been using for donkey’s years to strap sprained ankles and so on.
“This is a relatively new type of tape that is thin and light weight. The idea behind it is fascial unloading – reducing pressure in the tissue below the skin.”
Dr. Phil Newton remains dubious. “Looking at the tensile strength of the tape I don’t see how it could do it unless it is down to stimulating the senses. The power of placebo is very strong and shouldn’t be underestimated.”
He predicts the Olympics will be awash with the stuff. “It’ll be a show of multicoloured tape.”
“We’ll probably see athletes in the Olympics sporting a few union jacks made out of it,” he said.
Dr. Kenzo Kase certainly hopes so.
He said: “Olympians are very top athletes. Top athletes are very different from regular athletes. They are hypersensitive and they worry. My tape will give lots of comfort to them. This is not drugs.”