Cultural Variations in Placebo and Nocebo Effects

Almost everyone is familiar with the placebo effect. Patients who believe they have received an effective remedy tend to feel better and show improvement, even when the remedy is a sham treatment or chemically inert substance (known as a placebo). According to one review, "placebos can reduce pain, activate the immune system ... improve motor coordination in Parkinson's patients, and ameliorate asthma" (Henrich, 2016, p. 273).

Fewer people are familiar with nocebo effects. A nocebo is the opposite of a placebo. It's also a sham treatment, but the person believes he or she will be harmed in some way. Voodoo curses and magical hexes are examples of nocebos.

To say that placebo and nocebo effects are "just in your head" is seriously misleading. Sham treatments can cause measurable biological responses that induce the expected beneficial (or harmful) effect. Placebos (via the patient's belief system) can trigger the release of dopamine, a neurotransmitter associated with feelings of pleasure. Nocebos can deactivate dopamine and trigger anxiety via the hypothalamic-pituitary-adrenal axis (Henrich, 2016, p. 276).

Will the Placebo Have an Effect? Culture Matters

Placebo and nocebo effects are produced by specific beliefs that are acquired via cultural learning. Remedies or curses that don't have a direct impact on the body can work, but only when the recipient truly believes they will work. (The term "faith healing" takes on new meaning, yes?) A voodoo hex may work in Haiti, but it probably won't work in my small college town in Wisconsin. My neighbors may benefit from hypnotherapy, but the technique likely won't work in West Africa because not so many West Africans have a cultural script for hypnosis per se—although they may have one for a traditional healing trance.

Given that placebo and nocebo effects operate within a specific cultural context that accepts the treatment as legitimate, we should expect to see cultural variations in placebo and nocebo effects—and we do.

A review of past studies on placebo treatment for ulcers found that the average healing rate was much higher for German participants (59 percent) than it was for Dutch and Danish participants (22 percent). Studies in Brazil suggested that the placebo healing rate there (7 percent) was much lower than the overall rate (36 percent) in other countries (Moerman, 2000).

A Study of Cultural Beliefs and Mortality

In a clever study of the cultural specificity of nocebo effects, researchers found that individuals who held traditional Chinese beliefs about astrology and medicine lived shorter lives than their non-believing counterparts, but only when they were born in a particular year and suffered from a particular disease (Phillips, Ruth, & Wagner, 1993). Let me explain.

In traditional Chinese medicine, a person's fate is linked to their birth year, and every birth year is associated with one of the five phases: fire, earth, metal, water, or wood. Each phase is associated with a bodily organ or set of symptoms. Earth, for example, is associated with lumps and tumors. Fire is associated with the heart.

The researchers identified thousands of Chinese Americans who had a birth year ended in 0 or 1 (years associated with the lungs) and who suffered from bronchitis, emphysema, or asthma (lung diseases). On average, these star-crossed individuals died 4.5 years sooner than a comparable group of European Americans.

The difference was largest for individuals who were born in China (their life expectancy was lower by 6 years) or who lived in a Chinatown in San Francisco or Los Angeles (7 years). "The more strongly a group was attached to Chinese traditions, the more years of life were lost" (Phillips et al., 1993, p. 1142). The finding was not limited to lung diseases; the researchers identified similar patterns for cancer and heart attacks. While the exact nature of the cause-and-effect relationship between the variables could not be pinned down, the researchers posited that the findings "result at least partly from psychosomatic processes."

Culturally transmitted beliefs can and do exert strong influences on medical and psychotherapeutic outcomes, but the process itself goes easily unnoticed. It's only when we stop and look—when we systematically investigate cultural differences in cognition and behavior—that we come to appreciate the enormous power of culture.