Agopuntura e terapia del dolore: effetto placebo ?
Un articolo molto interessante svela l'esito di importanti studi sull'agopuntura e dei suoi effetti contro il dolore..
I risultati escludono la possibilità che l'agopuntura abbia solo un "effetto placebo" ed evidenziano la sua validità.
Articolo "Pains and needles: brain scans point to hidden effects of acupuncture" pubblicato su theguardian.com
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Doctors in China have been pushing needles into patients’ skin, supposedly to restore the flow of healing “qi energy”, for more than 4,000 years. Sometimes it feels as though researchers in the west have been arguing about the practice for almost as long. After more than 3,000 clinical trials of acupuncture, many scientists are convinced that despite the benefits that patients might think they experience, the whole thing is simply a highly convincing placebo.
But are the sceptics missing something? A steady trickle of neuroscience studies suggests that relying on patients’ pain ratings in acupuncture trials might be hiding important changes in the brain.
Just as they do with drugs, scientists test whether acupuncture works against a placebo – a convincing but sham alternative. Methods vary but this often involves placing needles at non-acupuncture points, and using retractable needles that don’t penetrate the skin. The aim is to control for the effects of patients’ positive belief in a therapy: simply thinking that your pain is about to decline can trigger the brain to release natural pain-relieving molecules called endorphins (a type of opioid, chemically similar to painkillers such as morphine). The central assumption is that such effects occur equally whether patients get a placebo or an actual treatment.
The key test, then, is the difference between the two: if both groups report the same level of pain relief, scientists conclude that the treatment being tested doesn’t work. When acupuncture is subjected to trials like this, there is only a small effect above placebo, and often no difference at all.
Sceptics argue that because of the lack of effect in clinical trials, such results are irrelevant. “It wouldn’t be at all surprising if being impaled with needles produced a signal in the brain,” says David Colquhoun, a pharmacologist at University College London and a prominent sceptic of alternative medicine. “It doesn’t tell you anything about how useful the needles are to patients.”
But a new generation of brain imaging studies is suggesting that perhaps researchers should refine their testing methods. There are now several trials showing that even when patients in acupuncture and placebo groups report similar drops in pain, the physical effects of treatment can be very different.
These are single studies, however, and not everyone is convinced. “I think there is nothing that can’t be explained by bad statistical practice and cherry picking of evidence,” says Colquhoun. He describes Harris and Napadow’s research as the sort of thing that merits the hashtag neurobabble (or even neurobollocks). “Looking for explanations of a phenomenon before there’s any proven phenomenon to investigate is a waste of time,” he insists.
But Harris is unfazed, arguing that regardless of the sceptics, wider opinion is moving towards an acceptance of acupuncture. “Some people are not willing to change, despite the evidence,” he says. “But gradually, we are seeing a shift.”