Your beliefs may impact your health.
Health and disease are influenced by multiple interacting factors, many of which are not fully under your control, including genetics, exposure to environmental toxins, history of trauma, and socioeconomic circumstances. But research suggests that beliefs matter too. In one study, middle-aged adults who held more positive beliefs about aging lived an average of 7.6 years longer (link is external) than those who held more negative beliefs, even when controlling for current health and other risk factors. In a number of other studies, optimistic people were found to be less likely to develop heart disease (link is external), again controlling for other risk factors.
Research on the placebo effect also supports the link between beliefs and health. Remarkably, the mere expectation that a treatment will be effective can sometimes make it so, even if that treatment is just a sugar pill. Although the placebo effect tends to be strongest for subjective reports of symptoms, sometimes in the absence of corresponding physical changes (link is external), there is evidence for some objective, measurable effects: For example, placebos can alter patterns of brain activation (link is external) associated with processing pain, and in Parkinson’s disease, placebos have been shown to elevate dopamine levels (link is external), which can temporarily improve symptoms.