How Real Is the Nocebo Effect? (Carol Tavris, February 23, 2026, Skeptic)
Where the placebo goes, can the nocebo be far behind? In This Book May Cause Side Effects, Helen Pilcher, a science writer and TV presenter with a PhD in cell biology, delves into the placebo’s “evil twin”—the myriad ways that our negative expectations affect us. If you had chills, fatigue, or headaches after getting a COVID shot, she writes, they were likely due to your being told those are frequent “side effects.” If you read the list of symptoms that your newly prescribed drug “might” produce, chances are you will experience one or more of them—and possibly decide not to take that drug after all. “If just the thought of eating a certain food makes you feel sick,” she writes, “it’s highly likely that placebo’s evil twin has struck again. Indeed, many of those who believe they have intolerances to certain ingredients, such as lactose or gluten, may well owe their misery to psychological rather than physical processes.” When self-reported “gluten intolerant” people are given gluten-free bread but told that the bread contains gluten, very often they develop gastrointestinal symptoms. “And when some gluten-intolerant people are covertly fed regular bread but told that it’s gluten-free, they don’t get symptoms,” Pilcher writes. “It’s the idea of gluten that they are intolerant to, rather than theprotein itself.”