30-Second Psychology: The 50 Most Thought-provoking Psychology Theories, Each Explained in Half a Minute - Christian Jarrett 2011
The placebo effect
Thoughts & Language
Expectations and context play an important role in how we respond to illness and in the effect that treatments have on us. The US anaesthesiologist Henry Beecher noticed this during the Second World War. Injured troops awaiting their return home displayed far less pain than usual. The reason, Beecher surmised, was that their injuries had come to signify a positive outcome. Similarly, the placebo effect is the benefit that arises from merely expecting a treatment will be beneficial. In drug trials, pharmaceutical companies have to test their products against inert sugar pills to show that any benefit is more than just the placebo effect. Some drugs, such as diazepam (for treating anxiety), are more powerful than placebo but only if the patient is told what the drug is for — in other words, the drug acts as a placebo amplifier. Similarly, morphine is less effective if the patient is unaware they are receiving it. The placebo effect is not ’all in the mind’. In the context of pain it works via the release of the brain’s own inbuilt painkillers — the opioids. If the brain’s opioid receptors are blocked with a drug called naloxone, the placebo effect disappears.
The mere expectation that a treatment will make you better is enough to set in train beneficial physiological processes in the brain and body.
The placebo effect has an evil twin known as the nocebo effect. This is when the expectation of harm or pain becomes a self-fulfilling prophesy, even in the absence of any known physical effect. One candidate for the nocebo effect is the discomfort some people report experiencing after using mobile phones. Scientists have failed to identify a physical cause, so it’s possible the adverse effects are caused by negative beliefs about the technology.
Even the colour of a pill can influence its effectiveness. Stimulants are more effective if they’re red, sedatives work better when they’re blue.