One thing that’s always surprised me about the way in which placebo effects are described is that they are portrayed as either the same as doing nothing, or as some kind of trick effect.
Clearly, giving a drug which randomised controlled trials show to be no more effective than placebo is not the same as doing nothing. Kirsch makes that very clear in the introduction to his book, “The Emperors New Drugs” where he shows the difference in depression between placebo groups and no treatment groups. But more than that, the placebo effect seems to be an integral part of the effect of any therapeutic intervention, whether that’s a drug or not. And, further, it’s not true that giving a chemically inert substance has no effect – it can produce what we call the placebo effect.
I recently read this article by Fabrizio Benedetti about the placebo effect and it’s one of the clearest articles on the subject I’ve ever read. He clearly maps out the chemical and neurological changes which occur in the body when a person is given a placebo. Here’s a small part of that description –
Placebo administration, along with verbal suggestions of analgesia (psychosocial context), might reduce pain through opioid and/or nonopioid mechanisms by expectation and/or conditioning mechanisms. The respiratory centers might also be inhibited by endogenous opioids. The β-adrenergic sympathetic system of the heart is also inhibited during placebo analgesia, although the underlying mechanism is not known (either reduction of the pain itself or direct action of endogenous opioids). Cholecystokinin (CCK) counteracts the effects of the endogenous opioids, thereby antagonizing placebo analgesia. Placebos can also act on serotonin-dependent hormone secretion, in both the pituitary and adrenal glands, thereby mimicking the effect of the analgesic drug sumatriptan.
Later in the article he points out that the chemical changes in the body don’t only occur in relation to pain pathways.
Although pain is the best known model to study placebo and nocebo effects, other conditions are now providing further insight into the biological mechanisms of placebos and nocebos. For example, patients who suffer from Parkinson’s disease have been shown to release dopamine after placebo administration [7] and also demonstrated changes in neuronal activity in the basal ganglia (fig. 5) [6]. Similar to the procedure in pain studies, patients were given an inert substance (placebo) and told they were receiving an anti-Parkinsonian drug that would produce an improvement in their motor performance. According to one hypothesis, the placebo-induced release of dopamine in Parkinson’s disease is related to reward mechanisms. In this case, the reward would be the clinical benefit.
This got me thinking. This is a good article for clarifying the REAL material changes which occur in human beings in response to the administration of inert substances. These changes are beneficial. Why don’t we study them more to understand them better, but, maybe even more importantly why don’t we stop thinking of these phenomena as something associated with trickery and deceit, but instead as important biological pathways in healing? The trouble is these pathways seem to be studied currently within the context of “dummy” and “pretend” interventions. Maybe we need to study them in relation to what are called “non-specific effects” – or in other words to the power of human care and interaction.
It’s time to change our priorities from a focus on technologies (drugs) to a focus on human beings (patients and practitioners)
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