The placebo effect is one of the most fascinating and interesting medical phenomena. At its most basic, a sugar pill given under the guise of authentic medication can actually cause a patient to get better.
But the placebo effect is far more complex than that.
For example, we know that two sugar pills have a greater effect than one, and that a salt water injection is a more effective pain killer than pills. Not that sugar pills or salt water injections on their own do anything physiologically to the body, but this is the effect we see.
And it isn’t just subjective things like pain that a person could lie about, or think they’ve noticed improvement in even if they haven’t. The placebo effect has been noted for improving conditions such as gastric ulcers and heart disease. You can’t fake what a doctor sees on endoscopy.
Surgery is one of the most potent placebo vehicles. Knee surgery where nothing is done other than cutting the skin has been shown to be as effective as a full arthroscopy, and, incredibly, the fitting of a pacemaker has improved the symptoms of heart failure without even being turned on.
Perhaps even more bizarrely, we know that factors such as the colour of a pill make a difference. It so happens that pink pills are more effective stimulants, while green pills are more effective sedatives.
It seems this is down to our expectations and culture. All our lives we identify pills, injections, and even surgery as medical treatment that must be good for us. Our expectation of getting better leads to us get better. Mind over matter. Simple.
But the effect runs deeper and stranger than that. Studies in which people are told they are taking a placebo still show improvement. Knowing you are taking something that should do you no good at all, and you still get better. And, for some reason, animals and children are affected (this is thought to be the transfer of parents' beliefs in a similar mechanism to rapport).
Don’t think the placebo effect is all good either.
Patients told a placebo will have a negative effect will suffer as a result. A study where asthmatic subjects were asked to inhale an inert mist demonstrated that the likelihood of them having an asthma attack varied depending on whether they were told it was an allergen or just vapour.
And a final oddity regarding the placebo effect; according to this study the effect of the placebo has increased in recent years (as has the effect of medication), as our expectations of medication increase.