Placebos

I have absolutely no context or knowledge about this issue, but this essay on the power of placebos was totally fascinating to me.

Modern medicine is good at breaking things down into parts and figuring out which parts “cause” different effects, but it is increasingly evident that when it comes to living beings the parts are less important than the relationships between them, which are themselves in flux. For decades modern neuroscience has been dominated by reductionists, and it is in sore need of some integration. Howick distills a wealth of modern neuroscientific research on placebos and nocebos, only to reveal how little we understand. He lists a few of the biomarkers observed to change in response to such treatments—oxytocin, endorphins, dopamine, cannabinoids, cholecystokinins—and describes changes within the DNA of what some researchers have gone so far as to call the “placebome”: genes that help us respond to placebos.

Hall takes a more neuroanatomical approach, writing of studies that imply that the vmPFC (ventromedial prefrontal cortex) is pivotal in placebo responses, because changes there “have been observed in multiple conditions known to have a high placebo response in clinical trials, including depression, attention deficit hyperactivity, substance misuse or addiction, schizophrenia, and dementia”—a range of conditions so wide that it’s difficult to see how her focus on the vmPFC adds clarity. More activity in a brain region doesn’t necessarily imply its involvement, in any case; it may simply represent excitatory or inhibitory responses to some primary action elsewhere in the brain. Connections, relationships, and networks are what’s important in the brain, not crude levels of activity.

Hall also quotes studies that show parts of the brain—namely the rostral anterior cingulate cortex and the periaqueductal gray—responding similarly both to taking a real opiate for pain and to taking a placebo. “Placebo effects could lead to the interception of incoming pain signals and exert ‘top-down’ control over the pain,” she speculates. In other words, your brain might have the power to stop pain signals from entering it via the spinal cord, simply because after a person takes a placebo the brain doesn’t expect them. We know that expensive placebos work better than cheap ones, capsules work better than tablets, and colored capsules work better than white ones. Blues and greens work better as sedatives, while pinks and reds work better as stimulants and painkillers. (Unless you’re an Italian man: Howick notes that blue is stimulating for Italian men, perhaps because the Italian soccer team wears blue.) Medium-size placebos are the least effective; it seems that we trust either tiny pills or big ones—the latter because they’re more impressive, and the former presumably because tiny capsules must contain powerful drugs.

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Opiates administered during labor can have dangerous sedative effects on the newborn, and recent studies have shown that giving the laboring mother injections of sterile water under the skin instead can reduce pain by 30 to 50 percent for up to ninety minutes, with no deleterious effects for the baby. But when British national guidelines suggested including water injections as an option for laboring women, there was an outcry from some commentators who felt that women’s experience of pain was being ignored or diminished. (The guidelines were careful to introduce water as an option, not as a substitute.) Dummy injections for pain have a pedigree: Howick tells the story of Henry Knowles Beecher, an American anesthesiologist posted to southern Italy during World War II whose morphine supplies ran out. He found that normal saline worked almost as well for his injured soldiers. Howick also describes a personal communication from an Italian doctor who gave a wealthy woman with a backache an injection of distilled water, which cured her pain: “She was so satisfied that seven days later she called me for the same reason and demanded the same solution, ‘which had done me so much good.’” As he was filling his syringe with water, the woman called out,“Doctor, is it a placebo that you are giving me?”He told her it was, and she replied, “Thank goodness. It helped so much last week.”

Again, I have no idea what to make of this. Part of me wants to believe that this is RFK quack stuff, but this is the New York Review of Books, which up to this point has had no tuck with his bullshit. But…I just don’t know. Seems like an interesting conversation piece though.