In Roald Dahl\u2019s 1980 masterpiece The Twits, Quentin Blake\u2019s illustrations demonstrate how Mrs\u00a0Twit\u2019s horrible attitudes eventually ended up deforming her looks. \u201cIf a person has ugly thoughts,\u201d wrote Dahl, \u201cit begins to show on the\u00a0face.\u201d<\/p>\n
In her latest book, science writer Helen Pilcher explores this very idea: that negative beliefs \u201ccan be physically transformative\u201d. The nocebo effect, as this is known, comes from the Latin for \u201cI will harm\u201d, and strikes when a\u00a0person\u2019s negative expectations, whether subconscious or conscious, lead to illness.<\/p>\n
This Book May Cause Side Effects is\u00a0a bold attempt to examine the anatomy of this phenomenon. In its simplest form it can be described as follows: \u201cwhen people are warned to expect symptoms, they become more likely to experience them\u201d. Much like the impossible instruction not to think of a pink elephant, if you are told a drug might\u00a0make you feel nauseous, it\u00a0is a\u00a0compelling psychological invitation to\u00a0experience it.<\/p>\n
In an analysis of 231 placebo-controlled clinical trials, Pilcher notes\u00a0that 76% of people in the experimental groups reported side-effects, compared with 73% of those who were on a placebo. \u201cMost of\u00a0us experience funny sensations in\u00a0the body at times,\u201d she writes, \u201cbut\u00a0the\u00a0nocebo effect is behind becoming\u00a0more aware of them, and misattributing them to a medication.\u201d<\/p>\n
Beyond drug side-effects, Pilcher\u2019s book explores the nocebo effect as it applies to a range of human conditions including ageing, \u201chex deaths\u201d, or the deaths of people who believed they had been cursed to die, and mass psychogenic illness.<\/p>\n
History is rich with examples of mass psychogenic illness, or MPI, such\u00a0as collective panic about shrinking genitalia in Asia, first recorded two millennia ago. It\u2019s the nocebo effect at scale. While in the past the pace of symptom contagion was limited by geography, today\u2019s lightning-fast global communication and the existence of social media platforms can make the nocebo effect\u00a0go viral.<\/p>\n
In 2014, social media is thought to have transmitted a mass psychogenic illness across Colombia. Children at a\u00a0girls\u2019 school began convulsing and fainting, having recently had the HPV vaccine, which protects against cancer of the cervix. Cases spread across the country and, although health officials found no link between the vaccine and\u00a0the symptoms, public confidence in the vaccine was shattered. From HPV immunisation rates of over 90%,\u00a0uptake dropped to\u00a05%.<\/p>\n
Whether people\u2019s nocebo effect symptoms can ever be physically verified is largely irrelevant. Subjective experience such as pain or fatigue lies behind a veil that we are unable to penetrate. Yet Pilcher also presents an array of research that shows measurable physical changes resulting from the nocebo effect. In one striking example, she cites a study\u00a0at Stanford in which participants were randomly told \u2013 regardless of their actual genetics \u2013 that they possessed a gene associated with either low risk or high risk of obesity. GLP-1, synthetic analogues of which include Ozempic, is\u00a0a natural hormone released by the body that makes us feel full. After a meal, those who were\u00a0told they had the \u201cskinny\u201d gene showed a significant increase in GLP-1, while those told they had the \u201cfat\u201d gene had no change\u00a0from their baseline levels.<\/p>\n
When interviewing a researcher who inserts electrodes into the brains of cancerous mice in an area associated with reward processing and positive emotion, Pilcher is gripped by the finding that stimulating this area curbs the cancer, and dampening it makes the cancer grow faster. \u201cThis is potentially huge. It\u2019s one thing to entertain the idea that mental processes can slow the growth of cancer,\u201d she observes, \u201cIt\u2019s quite another, however, to suggest that certain thoughts can make cancer worse.\u201d Pilcher has a dog in the race, revealing on the first page that she herself has a diagnosis of cancer. Yet, despite her caveats clarifying that the stimulation of a neuron in a mouse brain is not equal to a positive thought, the seed has been planted that this is the case. There is a risk that the folk intuition that makes Mrs Twit\u2019s metamorphosis credible in fiction \u2013 an intuition that chimes with the growing research on the nocebo effect \u2013 may feed into something morally repugnant.<\/p>\n
Ultimately, This Book May Cause Side Effects deals with the central philosophical quandaries of humankind: how we conceptualise mind and matter, and to what extent we can shape our own destinies. While\u00a0Pilcher steers away from tackling the philosophy head-on, this ambitious and fascinating book will add to our understanding of these mercurial and controversial questions. It could also help us avoid the nocebo effect in our daily lives. As side-effects go, that\u2019s a pretty good one.<\/p>\n