While researching the book Cure, science writer Jo Marchant wanted to understand how distraction could be used to nullify pain, so she participated in a virtual reality experiment.
During the first part of the experiment, Marchant sat, without distraction, with her foot in a box of unbearably hot water. "It felt like a very intense burning pain on my foot when I just experienced it on its own," Marchant tells Fresh Air's Terry Gross.
But then Marchant put on noise-canceling headphones and began to play a snow-and-ice-themed immersive video game that had been developed specifically for burn patients. This time, when the researcher applied the same burning pain to her foot, she barely noticed it.
"The researchers explained it as our brains only have a certain capacity for attention," Marchant says. "If you've got something that's really commanding your attention, there's less attention left over for experiencing the pain."
During the course of her research, Marchant also investigated the science behind the placebo effect, hypnosis, meditation, prayer and conditioning. She says that the healing power of the brain could offer a powerful complement to modern medicine. "That's a whole different approach to pain that I think tells us that drugs aren't the only answer," she says.
Interview Highlights
On harnessing the placebo effect to feel better
One thing that people often don't realize about the placebo effect is there isn't just one placebo effect. There are many, depending on what we think a treatment is going to do for us. So, for example, if you take a fake painkiller, that actually reduces pain-related activity in the brain and the spinal cord and it causes the release of natural painkillers in the brain called endorphins. And these are actually the painkillers that opioid painkillers are designed to mimic, so it's working through the same biochemical pathway that a painkiller would work through. But if a patient with Parkinson's takes a placebo that they think is their Parkinson's drug, they get a flood of dopamine in the brain, which is exactly what you would see with the real drug.
Even with altitude sickness, for example, if somebody at altitude takes fake oxygen, you see a reduction in ... prostaglandins. ... These actually work to dilate blood vessels and they cause many of the symptoms of altitude sickness.
So what you see in all these different conditions is that taking a placebo, or, to be more accurate about it, our response to that placebo, can cause biological changes in the brain that actually ease our symptoms, and that's not something that's imaginary; that's something that's underpinned by these biological changes that are very similar to the biological changes you get when we take drugs.
On possible explanations for why the placebo effect sometimes works
Some of it seems to have to do with stress and anxiety — if we feel that we are in danger or under threat, the brain raises its sensitivity to symptoms like pain. ... Whereas, on the other hand, if we feel that we are safe and cared for and things are going to get better soon, we can kind of relax, we don't need to be so alert to these symptoms. So that's one thing that might be at play.
There are also physiological mechanisms for example, conditioning. ... If listeners are familiar with Pavlov's dogs, so this is the idea that a physiologist called Ivan Pavlov conditions dogs so that whenever he gave them their food he would make a noise, like ring a bell for example, and eventually they came to associate the bell with their food and they would salivate just to the sound of the bell. He didn't need the food anymore. We can all be conditioned to have different physiological responses to a stimulus like that, and that works not just for salivation, but for things like immune responses. So, for example, if you take a pill that suppresses your immune system, later on, if you take a similar looking placebo pill, even if there's no actual active drug in there, your body will mimic that same response. Your body has learned that response and that just happens automatically; it doesn't matter what you believe about the pill.
On making sense of placebo responses
I don't think we should be giving people fake pills. I think, first of all, there is some evidence that honest placebos still work, so there are studies in various conditions, for example — irritable bowel syndrome, headaches, hyperactivity disorder — where patients have received placebos but they knew they were placebos and still got a benefit from that. And that's probably all down to things like just being in a trial, the feeling that you're being helped can have those effects on the brain. So you don't necessarily have to lie to people, but beyond that, I think what we need to do is try and understand what are the active ingredients of placebo responses — whether that's expectation, which is then influenced by all different things, such as your previous experiences with treatment, what you're told about a treatment, how sympathetic your physician is. There's all sorts of things that are feeding into how you'll respond to that treatment. So I think we need to try and understand those things and think how we can incorporate those elements into medical care routinely, rather than, for example, relying on fake pills.
On how meditation and mindfulness can affect health
The basic idea [of mindful meditation] is that you try to focus on the present moment rather than worrying about the past or the future. ... There have been hundreds of studies on mindfulness now, and there's very good evidence that it reduces stress and anxiety, and that it reduces symptoms such as chronic pain and fatigue. So that's very well shown now in the analysis of lots of different studies, and that's in healthy people but also in people with depression or people with serious illness. What there's less research on is whether that feeds through into benefits for the immune system and sort of more physical health benefits, if you like.
There is some evidence suggesting that mindfulness meditation can make us more resistant to infection and that's everything from winter colds to slowing the progression of HIV and that it gives people a better response, for example, than flu vaccine. There was another study suggesting that people with psoriasis responded better to their medication when they also had mindfulness training. ... But the studies so far are quite small, so it would be great to see more research on that.
On why slow, measured breathing helps with stress
With a stress response, the brain and the body are influencing each other in both directions, so if we see a danger then that's going to make us feel stressed and one of the follow-ons from that is that our breathing is going to speed up. If you were to speed up your breathing on your own, you'd probably start to feel a bit more aroused and on edge. And, equally, if you calm the breathing down, you're kind of forcing your body into a more relaxed state and you will then experience probably fewer negative thoughts as a result. When we're stressed, our brains almost come up with negative thoughts to try and explain why we're stressed, if you like, if you're kind of anxious or worried about something, all sorts of negative thoughts are going to pop into your head, but if you can just calm that down, then that's going to have a beneficial effect on your mental state as well.
On how how stress can rewire the brain — and creates more stress
Your brain reflects the way that you think throughout your life. You kind of shape it by your thoughts and your behaviors. If you play violin for eight hours a day, then the parts of the brain responsible for helping you to play the violin will get larger. If you're thinking stressful thoughts for the whole day then those parts of the brain are going to get larger and other parts of the brain will deteriorate. It's kind of an irony because then the very brain circuits that we would need to try and counter that are no longer working as well as they should, so that's why something like meditation can be helpful because just simply saying, "Oh, I'm going to change how I think now. I'm not going to be as stressed now," doesn't really work; you have to change your brain over a long period of time.
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