By Sudi de Winter
Imagine this scenario. Your child is running down the hall, trips and lands headfirst.
Now consider these two different responses.
I saw you trip and fall. It will be alright. Let me kiss it better.
Oh my God! You banged your head. You could have killed yourself!
We all know these contrasting approaches would produce different reactions in the child. The first reaction is an example of placebo and the second could be described as the opposite effect, nocebo.
However, you may not appreciate the physical and chemical changes occurring during these events.
A common misconception about placebo is that it is merely a non-specific, psychological effect occurring in the suggestible person. Yet incredible research over the last two decades has transformed our understanding of these placebo phenomena.
Professor Fabrizio Benedetti is a pre-eminent placebo researcher and his work has demonstrated the specificity in various placebo effects. For example, if someone is given opioids for three days (conditioning), and then on the fourth day given a placebo, the brain will produce its own opiates from its own ‘drug cabinet’. These endogenous opioids will use the same pathway as the conditioning opiates.
Yet if someone is conditioned with cannabinoids (a different class of drugs – one example is cannabis) and then given a placebo, the brain will produce its own cannabinoids and light up that pathway. The same placebo effect specificity is seen with aspirin conditioning, some immune suppressants, some hormones and many other drug systems. Even in Parkinson’s disease, if patients are conditioned, sham electrical brain stimulation will create a 200% increase in dopamine, and motor function will markedly improve, albeit temporarily.
Basically, once the body has learnt a response, it is capable of mediating that same response solely through the power of expectation and ritual (pill, injection, procedure etc.).
These are conscious placebo effects, as the power of expectation is crucial. Interestingly, if someone is given an active drug through hidden administration, its effect may be greatly diminished compared to the patient who is aware of and expecting drug administration.
There are also examples of unconscious placebo effects. For example, if someone takes a round, white pill and knows it is a placebo there may be physiological effects occurring in various drug pathways, regardless of the person not expecting any effect. In this case, the ritual alone is enough to trigger chemical mediators.
In fact, the more complex the ritual, the greater the placebo effect. Surgery has been described as the ultimate placebo due to its elaborate machinations. White coats, important surgeons, anaesthesia, and sharp knives. Sham knee meniscal surgery trials (anaesthesia and incision only) have produced superior outcomes to the actual meniscal surgery.
Studies have also shown more expensive, brand name medication to be more effective than cheaper, generic versions (for example, Nurofen versus ibuprofen). Here, marketing complicates the ritual and expectation picture. The other day I bought a brand name, specifically due to this! It’s madness!
Health care practitioners must juggle placing ethics and honesty first and yet attempt to not completely demolish placebo effects.
As Fabrizio Benedetti says, “Our words alone move a lot of molecules around in the patient’s brain.” Next time my kid falls, I’m going to maximise the placebo by using the most effective child placebo: kissing it better!
Cure: the science of mind over body. Jo Marchant – Very accessible and entertaining.
Placebo effects. Fabrizio Benedetti – More clinical, in-depth look into the science of placebo.