How media might make you sick: Exploring the nocebo effect
Media reports on health problems can actually make you sick, even if you don't have an underlying disease or illness and aren't aware of it. When we read or see something in the media about health and disease or illness that seems relevant or important, we are influenced. The information we receive shapes our expectations, which in turn affects our perceptions as well as our bodies. These processes often happen subconsciously, without our control or conscious choice.
Our brain continuously predicts what will happen, based on past experiences—a central hypothesis in neuroscience and psychology. The brain receives a flood of information from both the body and the environment and has to decide what to focus on. In addition, it needs to add information that is lacking, i.e. to make assumptions. In this process, our expectations play a crucial role in helping the brain prioritize, to work effectively. The brain functions like a skilled meteorologist, constantly predicting the weather, always trying to anticipate what will happen in the body based on past experiences—staying one step ahead using our expectations. When our expectations don't match the information our senses receive, the brain adjusts its assumptions, or how the information is perceived. This way, we can navigate the world without spending too much time processing all the information our senses register.
But sometimes things go wrong—our expectations can become so strong and dominant that they completely override signals, or the lack of signals, coming from the body. For example, you might feel itchy if you read about lice or feel nauseous if you think you've eaten bad food. You might even experience pain if you believe you have a foreign object in your body. This is called the nocebo effect, the "evil twin" of the placebo effect. An example of expectations filling in for missing signals is when one in four people experiences side effects from a dummy pill. These negative reactions to placebo pills are even more pronounced if people have prior experiences with side effects, such as during past treatments, or when negative information accumulates. They receive a placebo, but still experience side effects like fatigue, pain, nausea, dizziness—a purely expectation-driven effect. Another example of the nocebo effect occurred when a postal worker opened a letter, causing harmless flour to spill out. Believing it might contain anthrax—a substance used in deadly terror attacks—the worker and 39 others developed real symptoms and appeared very sick when they arrived at the hospital, with 14 being placed in isolation. Testing later confirmed that the flour was harmless, highlighting how fear and expectation can lead to genuine illness.
Our model of reality, shaped by what we see in the media, can amplify or even produce both physical and psychological symptoms. If the media have a tendency to amplify negative information (“If it bleeds, it leads”), this can contribute to the development of a nocebo effect. In this way, media reports about serious vaccine side effects can heighten your reaction to that very vaccine, or reports about long-term effects of COVID-19 can trigger or create symptoms in others. If the course of an illness is unwarrantedly described in media as negative and not justifying any hope, this can hinder the recovery process in patients.
Symptoms that have been associated with the nocebo effect includes:
· Neurological Symptoms:
o Fatigue, headaches, dizziness, and light sensitivity
o Trembling, seizures and shaking
· Pain and Muscle Issues:
o General pain
o Muscle pain, cramps, and weakness
· Respiratory Symptoms:
o Difficulty breathing and chest tightness
o Sweating and hot flashes
· Gastrointestinal Symptoms:
o Nausea, vomiting, and severe stomach pain
o Diarrhea, constipation, dry mouth, and bloating
· Skin Reactions:
o Rashes, itching, and swelling
· Psychological Symptoms:
o Anxiety, depression, and irritability
o Sleep problems like insomnia and disrupted sleep patterns
· Other Symptoms:
o Hearing loss and erectile dysfunction
The list is extensive but not exhaustive.
Greater awareness of how the media influences our thoughts, expectations, and health can help us make better-informed choices and reduce the risk of the nocebo effect. If journalists and media professionals increase their understanding of the nocebo effect, we can hopefully minimize harm and misconceptions. By being more critical of how health information is presented, we can contribute to more balanced and responsible media coverage that protects, rather than harms, people's health.
Further readings: Bernstein et al., 2024 The nocebo effect: when words make you sick