The Rev Dodgson said:
I’m not even remotely close to an expert in this area, but as far as I have seen (which obviously is not very far), when people investigate whether placebos have any effect, they find that they do.
How this ties in with the vast number of experiments where it is just assumed that they don’t work, I don’t know, but it seems like an area worth investigating, rather than dismissing the whole thing.
I’m not an expert either. The general misunderstanding of the Placebo Effect is a bugbear of mine, and this could very well mean that the Google-fu research I have done on it is full of my own biases (confirmation bias for example).
It’s also true that anything I write about the Placebo Effect is a simplistic account of what is a complex question.
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http://www.sciencebasedmedicine.org/the-placebo-effect/
“In order to demystify the placebo effect, I will try to first describe exactly what it is. The operational definition of a placebo effect is any health effect measured after an intervention that is something other than a physiological response to a biologically active treatment. In clinical trials the placebo effect is any measured response in the group of study subjects that received an inert treatment, such as a sugar pill. However, “the placebo effect” is a misnomer and contributes to confusion, because it is not a single effect but the net result of many possible factors.
“The various factors that contribute to a measured or perceived placebo effect vary depending upon the situation – what symptoms or outcomes are being observed. Subjective outcomes like pain, fatigue, and an overall sense of wellbeing, are subject to a host of psychological factors. For example, subjects in clinical studies want to get better, they want to believe they are on the active experimental treatment and that it works, they want to feel that the time and effort they have invested is worthwhile, and they want to make the researchers happy. In turn, the researchers want their treatment to work and want to see their patients get better. So there is often a large reporting bias. In other words, subjects are likely to convince themselves they feel better, and to report that they feel better, even if they don’t. Also, those conducting a trial will tend to make biased observations in favor of a positive effect.
“It has also been clearly demonstrated that subjects who are being studied in a clinical trial objectively do better. This is because they are in a clinical trial – they are paying closer attention to their overall health, they are likely taking better care of themselves due to the constant reminder of their health and habits provided by the study visits and attention they are getting, they are being examined on a regular basis by a physician, and their overall compliance with treatment is likely to be higher. So basically, subjects in a trial take better care of themselves and get more medical attention than people not in trials. If for those not in a clinical trial, if they decide to do something about their health by starting a new treatment, they are likely to engage in more healthful behavior in other ways.
“A common belief is that the placebo effect is largely a “mind-over-matter effect,” but this is a misconception. There is no compelling evidence that the mind can create healing simply through will or belief. However, mood and belief can have a significant effect on the subjective perception of pain. There is no method to directly measure pain as a phenomenon, and studies of pain are dependent upon the subjective report of subjects. There is therefore a large potential for perception and reporting bias in pain trials. But there are biological mechanisms by which mental processes can affect pain. There are many non-specific factors that can biochemically suppress pain. For example, increased physical activity can release endorphins that naturally inhibit pain. For these reasons the placebo effect for pain is typically high, around 30%.
“But the more concrete and physiological the outcome, the smaller the placebo effect. Survival from serious forms of cancer, for example, has no demonstrable placebo effect. There is a “clinical trial effect,” as described above – being a subject in a trial tends to improve care and compliance, but no placebo effect beyond that. There is no compelling evidence that mood or thought alone can help fight off cancer or any similar disease.
“Other conditions are more objective than pain, but are special because they have a strong influence from the neuro-endocrine system. This system translates psychological stress into physical stress, by releasing stress hormones and increasing activity in the sympathetic nervous system. So, for example, for heart disease mood matters quite a bit. Someone who has an A-type personality and is always angry and upset is at higher risk of a heart attack than someone who is mellow and unstressed. But here there is a known physiological connection between mood and a specific organ – the heart. This cannot be extrapolated to other diseases; it doesn’t mean you can smile your cancer away.
“Many people talk about the neuroendocrine system’s effect on the immune system. Again, here there is a physiological connection. Stress hormones do suppress the immune system, and it is probably true that extreme stress leaves us physically susceptible to disease for this reason. But the effects of moderate levels of stress are not established. Also, we cannot extrapolate from the risk of getting a cold to the ability to fight off cancer. You have to look at the evidence for each disease unto itself. So while this is a potential contributor, it is overall probably a small effect except in extreme situations….
“Therefore the placebo effect is fairly complex and is largely an artifact (sic) of observation and confounding factors. Any real benefits that contribute to the placebo effect can be gained by more straightforward methods – like healthy habits, compliance with treatment, and good health care. The placebo effect is not evidence for any mysterious mind-over-matter effect, but since the mind is matter (the brain) and is connected to the rest of the body, there are some known physiological effects that do play a role (although often greatly exaggerated).”