The ‘Nocebo’ Effect
You’re no doubt aware of the placebo effect — the medication that can make you feel better, even though it doesn’t really do anything.
The word placebo has its origins in the Latin for “to please”. Over the years it has come to be used as the name for an inert or simulated medical therapy, such as a sugar pill, saline injection or sham procedure, that is used because it is not going to do anything.
But did you know there’s an equivalent effect when you think the medication’s going to make you worse-off?
This is known as the nocebo effect. For example, you can think that a medication’s going to give you muscle pain — perhaps because that’s listed as a side effect on the packaging — and even if your pill has no active ingredients, it can still cause you pain.
“We can get worse and experience unintended side effects when we have an expectation of worsening symptoms like pain and nausea, tremor and so on,” Associate Professor Luana Colloca, a researcher at the University of Maryland, told the Health Report.
This matters, because it can limit how effective treatments are, and even dissuade patients from continuing to take important medications.
What Causes the Nocebo Effect?
There’s a range of stimuli that can cause a nocebo reaction, Dr Colloca said.
Among them are your prior experience with a medical treatment, the words and phrases a doctor uses when prescribing something to you, claims you’ve heard in the media or from comments your friends have made about certain drugs. Sometimes the colour, packaging or marketing can have an impact.
“Words are critical. Indeed, the kind of information we use to inform patients can make a huge difference, and usually we anticipate the negative outcomes or the adverse events that are associated with medications,” Dr Colloca said.
One example is the way doctors describe injections.
It’s commonly thought that by forewarning a patient that something painful is about to happen, their pain and anxiety is reduced — because they’re ready for it.
But research has shown that heralding that injection with particular words or phrases — among them “sting”, “burn” or “bad” — actually increased the pain and anxiety in those getting the injection.
Expensive Taste Brings the Pain
It’s not just what a doctor says that can shape your expectation, either. In a recent study published in Science looking at the nocebo effect, the price of two different treatments also emphasised the effect.
In the study, patients were asked to try one of two dermatitis creams — one of which was presented as expensive, the other less so. They were also told that the cream would enhance their sensitivity to pain. In reality, both creams were placebos and had no active ingredients.
The researchers then zapped both groups with flashes of heat.
They found that those patients who thought they were using the expensive cream reported feeling more pain from the heat flashes, and had more brain activity in their prefrontal cortex and certain spinal cord regions associated with pain.
Not Just in Your Head
The activation of those brain areas is key to understanding the nocebo effect, Dr Colloca said, because it shows that it’s not just “in your head”.
“It’s not just in your brain, it’s something that we believe and the brain reacts to this kind of information,” she said.
That in turn alters the pain modulation system in the brain — activating regions associated with pain like the spinal cord and the anterior cingulate cortex.
How Should Doctors Tell You About Side Effects?
Patients need to be told about the potential side effects of a medication they’re taking, so they can agree to taking them while understanding the risks — known in the medical profession as “informed consent”.
But Dr Colloca said while informed consent was vital, doctors could also think about the way they present the risks to limit the nocebo effect taking hold.
She said particular attention should be paid to how negative effects are framed and balanced against the positive outcomes of a drug.
“We can inform patients about nocebo effects, but also we can tell them that 10 out of 100 patients experiences these side effects,” Dr Colloca said.
“So framing effects using percentages in a positive way or in proportion [is important].
“We need to have a greater balance between the truthful information related to the side-effects, as well as the positive outcome.”