Medical Learning Objective: The Placebo Effect
Special Series: Medical Learning Objectives
- Medical Learning Objective: The Placebo Effect
- Medical Learning Objective: Three Lessons Learned About Science, And The Humans Who Do It
I have no idea how the placebo effect didn’t make my list of medical learning objectives for all, but consider it summarily appended.
The placebo effect is an often misunderstood concept in medicine, but is vastly important to understanding how we humans respond to medical treatment. It is used to describe situations where patients with a condition receive an intervention that is inert, or doesn’t do anything to objectively fix their medical problem, but said patients still report some degree of improvement anyway. This has nothing to do with content of the placebo treatment itself, be it a sugar pill, salt water injection, or an ineffective surgical procedure. Instead, the phrase “placebo effect” encompasses a multifactorial web of things about the act and ceremony of a person being treated for a specific illness that can modify their perception of their condition for the better.
Muddying this issue a bit is the fact that the same phrase is used in two different settings, in which it has different meanings. In the scientific sense, the placebo effect describes a specific, measurable effect in a clinical trial of a group of patients who received an ineffective treatment, compared to another group in the same trial who received an active therapy for whatever condition is being studied. This results in numbers that can be compared with statistical analyses to determine exactly how good a certain active treatment works for a particular condition in a particular setting. In the therapeutic sense, it refers to a health care provider giving a patient a treatment that the provider knows should not actively treat the patient’s condition, but doing so with the intent that the patient will feel better not because they received a medication that works, but due to the very act of being treated itself. Obviously, such a practice would raise huge potential ethical issues.1
Image via Wikipedia
While the elements of how an inactive therapy can cause notable improvement in a patient’s illness are complex and incompletely understood in some cases, there are several key aspects to the placebo phenomenon we are certain of:
- Since the placebo effect is a result of the modification of a patient’s response to therapy, it is most profound in subjective medical conditions, such as pain.
- There is no such thing as a single consistent placebo effect; in clinical trials of the same illness, it can vary from study to study due to the unique circumstances of each group of patients involved.
- The placebo effect is not the direct result of an inert treatment, but is a result of a patient’s mental response to that treatment experience, and how it is given.
Knowing what the placebo effect is – and is not – is critically important to understanding the results of studies on medical therapies. The placebo effect is a very real, measurable, and variable phenomenon in clinical trials that speaks to how we as human beings perceive being treated for illness. It represents the complexity of things that need to be taken into account when designing and interpreting clinical trials, in order to better understand disease and confirm how well a specific treatment actually works. In a couple of days, we’ll take a look at a recent major study that is an excellent example of the placebo effect in action, and how it can be badly misinterpreted.
Some further reading can be found here, here, and here.
Here, Dr. Ben Goldacre discusses the placebo effect:
Here, Dr. Goldacre uses some NSFW (consider yourself warned) language in a highly entertaining way to make points about the placebo effect, by comparing it to the nocebo effect – the concept that in certain circumstances, undergoing an inert treatment can cause negative effects on someone instead of positive:
- What’s interesting is that, in some cases, patients can be told that the treatment they are receiving is a placebo, and they will still experience an improvement anyway – just because someone is consciously aware that they are getting an inert therapy doesn’t mean that they can’t still experience a placebo effect from it. [↩]
Tags: John Cmar, medical learning objectives for all, medical literature for the non-medically trained, placebo effect
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