UNDERSTANDING THE ROLE OF EMOTIONS IN HEALTH
Perspectives on Emotion and Health: An Overview
Emotions can affect health in numerous ways. Perhaps the most well-appreciated is that chronic illnesses present significant challenges in terms of psychological adjustment. Individuals not only have to navigate various physical symptoms and related emotional and social stressors in the time surrounding diagnosis and treatment, they also have to adapt to the longer-term consequences of disease and treatments (e.g., persistent pain, fatigue, cognitive impairment). Illness-related emotional experiences range from transient feelings of vulnerability, sadness, and fear, to conditions that can be long-lasting and more disabling, such as clinically significant depression and anxiety.1 While many patients who develop chronic disease often report relatively low levels of psychological distress, prevalence of clinically relevant disorders (e.g., anxiety, depression) tends to be higher in these patients than in the general population. For example, the rate of major depressive disorder is two- to threefold higher in patients with cancer2 or cardiovascular disease (CVD).3,4 Psychological distress associated with illness and medical treatments is consequential for subsequent health outcomes. For instance, depression is linked to increased healthcare use,5 poorer adherence to medical treatment,6 and elevated risk for suicidal thoughts and actions in patients treated for cancer.7 Depression and anxiety are related to poorer quality of life and daily functioning in cancer and CVD patients.5,8 Conversely, indicators of psychological well-being, such as optimism and a capacity to experience positive emotions, suggest better adjustment to illness.9
Much has been written on emotions as a consequence of disease or as part of the disease management process (for more discussion on psychological adjustment to disease, see Hoyt and Stanton9), whereas the hypothesis that emotions play a role in health maintenance or disease development is more controversial.10 However, substantial empirical evidence from the past decades has strongly suggested a causal relationship. In light of the evidence and to address the scarcity of resources for clinicians on this topic, in this chapter we focus on the role of emotions in disease development and health maintenance.
The pathways by which emotion influences health in different stages of illness (i.e., development, triggering, exacerbation, or progression of disease) are likely to differ. Thus, findings on effects of emotion on health do not necessarily generalize from the general population to patients (and vice versa). Hence, we prioritize research conducted in the general population aimed at understanding whether emotions influence the likelihood of developing disease. When relevant, we also discuss research showing how emotions influence disease progression in already-ill patients (e.g., recurrence or secondary episode of an illness, or exacerbation of symptoms). In addition, we recognize recent literature suggesting that the effects of different emotions are not uniform. In early research, investigators assumed that apparent health-beneficial effects of positive emotions were not due to unique effects of positive emotions per se, but rather because ...