The nocebo effect—as the name implies, the evil twin of the placebo effect—is topic of a multi-national study just put into a book. It details how negative expectations concerning health can make a person sick, just as the placebo effect can have unexplained positive health results. Author Charlotte Blease, of Sweden’s Uppsala University, says the nocebo effect was documented a long time ago, but it was especially obvious during the coronavirus pandemic. In a study of forty-five thousand people, about one-half were injected with a saline solution instead of the virus vaccine. Many who received the placebo reported nausea and headaches they expected from the vaccine—the vaccine they didn’t get. The book, The Nocebo Effect, suggests expectations matter.