Rethinking the Placebo Effect: How Our Minds Actually Affect Our Bodies

The startling physiological effects of loneliness, optimism, and meditation.

In 2013, Neil deGrasse Tyson hosted a mind-bending debate on the nature of “nothing” — an inquiry that has occupied thinkers since the dawn of recorded thought and permeates everything from Hamlet’s iconic question to the boldest frontiers of quantum physics. That’s precisely what New Scientist editor-in-chief Jeremy Webb explores with a kaleidoscopic lens in Nothing: Surprising Insights Everywhere from Zero to Oblivion (public library) — a terrific collection of essays and articles exploring everything from vacuum to the birth and death of the universe to how the concept of zero gained wide acceptance in the 17th century after being shunned as a dangerous innovation for 400 years. As Webb elegantly puts it, “nothing becomes a lens through which we can explore the universe around us and even what it is to be human. It reveals past attitudes and present thinking.”

Among the most intensely interesting pieces in the collection is one by science journalist Jo Marchant, who penned the fascinating story of the world’s oldest analog computer. Titled “Heal Thyself,” the piece explores how the way we think about medical treatments shapes their very real, very physical effects on our bodies — an almost Gandhi-like proposition, except rooted in science rather than philosophy. Specifically, Marchant brings to light a striking new dimension of the placebo effect that runs counter to how the phenomenon has been conventionally explained. She writes:

It has always been assumed that the placebo effect only works if people are conned into believing that they are getting an actual active drug. But now it seems this may not be true. Belief in the placebo effect itself — rather than a particular drug — might be enough to encourage our bodies to heal.

She cites a recent study at the Harvard Medical School, in which people with irritable bowel syndrome were given a placebo and informed that the pills were “made of an inert substance, like sugar pills, that have been shown in clinical studies to produce significant improvement in IBS symptoms through mind-body self-healing processes.” As Marchant notes, this is absolutely true, in a meta kind of way. What the researchers found was startling in its implications for medicine, philosophy, and spirituality — despite being aware they were taking placebos, the participants rated their symptoms as “moderately improved” on average. In other words, they knew what they were taking wasn’t a drug — it was a medical “nothing” — but the very consciousness of taking something made them experience fewer symptoms.

This dovetails into recent research confirming what Helen Keller fervently believed by putting some serious science behind the value of optimism. Marchant sums up the findings:

Realism can be bad for your health. Optimists recover better from medical procedures such as coronary bypass surgery, have healthier immune systems and live longer, both in general and when suffering from conditions such as cancer, heart disease and kidney failure.

It is well accepted that negative thoughts and anxiety can make us ill. Stress — the belief that we are at risk — triggers physiological pathways such as the “fight-or-flight” response, mediated by the sympathetic nervous system. These have evolved to protect us from danger, but if switched on long-term they increase the risk of conditions such as diabetes and dementia.

What researchers are now realizing is that positive beliefs don’t just work by quelling stress. They have a positive effect too — feeling safe and secure, or believing things will turn out fine, seems to help the body maintain and repair itself…

Optimism seems to reduce stress-induced inflammation and levels of stress hormones such as cortisol. It may also reduce susceptibility to disease by dampening sympathetic nervous system activity and stimulating the parasympathetic nervous system. The latter governs what’s called the “rest-and-digest” response — the opposite of fight-or-flight.

Just as helpful as taking a rosy view of the future is having a rosy view of yourself. High “self-enhancers” — people who see themselves in a more positive light than others see them — have lower cardiovascular responses to stress and recover faster, as well as lower baseline cortisol levels.

Marchant notes that it’s as beneficial to amplify the world’s perceived positivity as it is to amplify our own — something known as our “self-enhancement bias,” a type of self-delusion that helps keep us sane. But the same applies to our attitudes toward others as well — they too can impact our physical health. She cites University of Chicago psychologist John Cacioppo, who has dedicated his career to studying how social isolation affects individuals. Though solitude might be essential for great writing, being alone a special form of art, and single living the defining modality of our time, loneliness is a different thing altogether — a thing Cacioppo found to be toxic:

Being lonely increases the risk of everything from heart attacks to dementia, depression and death, whereas people who are satisfied with their social lives sleep better, age more slowly and respond better to vaccines. The effect is so strong that curing loneliness is as good for your health as giving up smoking.

Marchant quotes another researcher, Charles Raison at Atlanta’s Emory University, who studies mind–body interactions:

It’s probably the single most powerful behavioral finding in the world… People who have rich social lives and warm, open relationships don’t get sick and they live longer.

Marchant points to specific research by Cacioppo, who found that “in lonely people, genes involved in cortisol signaling and the inflammatory response were up-regulated, and that immune cells important in fighting bacteria were more active, too.” Marchant explains the findings and the essential caveat to them:

[Cacioppo] suggests that our bodies may have evolved so that in situations of perceived social isolation, they trigger branches of the immune system involved in wound healing and bacterial infection. An isolated person would be at greater risk of physical trauma, whereas being in a group might favor the immune responses necessary for fighting viruses, which spread easily between people in close contact.

Crucially, these differences relate most strongly to how lonely people think they are, rather than to the actual size of their social network. That also makes sense from an evolutionary point of view, says Cacioppo, because being among hostile strangers can be just as dangerous as being alone. So ending loneliness is not about spending more time with people. Cacioppo thinks it is all about our attitude to others: lonely people become overly sensitive to social threats and come to see others as potentially dangerous. In a review of previous studies … he found that tackling this attitude reduced loneliness more effectively than giving people more opportunities for interaction, or teaching social skills.