Biology, Emotion, Stress, and Health

Two final points merit brief comment. The first focuses on the nature of the biological systems involved in emotional behavior and the second on connections between emotion and health.

Biological Basis of Emotion. Panksepp marshaled an impressive array of neuroscience data in support of the position that specific neurobiological systems underlie the primary affects; the base for the primary emotions lies deep in the upper portion of the brain, not in the peripheral autonomic system.

The chemistries of the body (e.g., epinephrine, dopamine, a vast array of peptides, and notably insulin, cortisol, and other agents involved in the storage and availability of sugars for energy expenditure) affect this central system because the brain and body are in bidirectional communication with one another. It is interesting to note that these chemistries regulate communication and social regulation even in single-cell bacteria. Insulin equivalents that transport sugars into the cell communicate the presence of food to conspecifics and regulate the behavior of the colony.

This may be seen as a parallel to the action of the mammalian brain, which facilitates intraspecies emotional communication by connecting emotional reactions to a broad cognitive base. A bacterium will not release a sufficient amount of this insulin-like factor to capture a nutrient unless other members of its local community also detect the nutrient. Communicating with one another precludes the premature use of this resource in the presence of a limited quantity of nutrient.

Although these functions do not depend on the presence of a central nervous system, as in multicellular organisms, the action of such chemical systems may provide insight into the origins and function of complex emotion systems.

The neurobiological substrates for affective processes are currently the subject of intense investigation. Accumulating evidence has informed theory regarding the role of systems involving the prefrontal cortex, hippocampus, and amygdala in generating affective experience, emotional communication, and other behavioral expressions of affect and motivation.

This work has also stimulated the rethinking of the distinction between cognition and emotion given that common as well as separate neurobiological structures have been implicated in both functions. In sum, the biological description of the emotion system is being linked to functional analyses in showing that emotions are critical sources of information for the regulation of resources, interpersonal behavior, and survival.

Emotion, Health, and Illness. The virtual elimination of life-threatening respiratory and gastrointestinal infections, the extension of life into the seventh and eighth decades, and the emphasis on autonomy and self-control in industrialized Western nations confront us with the chronic diseases of old age. One result has been the need for effective forms of self-management for prevention and control of chronic conditions and the revival of, it is hoped, life-improving folk medicine.

Billions of dollars are spent annually on natural herbal products, mega-vitamins, special diets, stress-control programs, biofeedback, and so forth for the prevention and treatment of disease. The reduction of stress and avoidance of negative affects are culturally accepted, alternative routes for prevention and treatment.

With the exceptions perhaps of cardiovascular disease and the common cold, however, there is scant evidence for such a direct, causal role of stress or negative emotion on disease, although the evidence for an indirect role is abundant (e.g., through the motivation of risk behaviors such as cigarette smoking and excessive alcohol consumption). Life-style behaviors related to emotional and motivational processes are critical not only for the prevention of chronic illness but also for their control.

For example, exercise, dietary control, and weight loss are nearly twice as effective as medication for preventing the onset of diabetes among individuals at very high risk. Despite the evidence, many people seem more concerned about reducing stress than quitting smoking, exercising, and reducing saturated fats in the diet, which may be far more likely to reduce the possibility of serious disease.

What lends credence to the commonsense belief that stress causes disease? Clearly stress makes us feel bad and stress reduction makes us feel better. Because physical illness and emotional states are bidirectionally related, fatigued and depressed mood often both precede and follow the onset of clinical illnesses such as the common cold.

The immunological responses that defend us against disease have direct effects on the central nervous system; they cause fever and shivering, inhibit motor behavior and eating, and create fatigue and its associated feeling state of depressed mood.

Thus, rather than seeing emotional states as directly causing disease, it might be closer to the truth to see emotional states as indicators of active disease processes and of reduced resistance to disease. Just as our thermometers tell us the temperature without causing the weather, so too might emotions indicate that something is amiss without directly causing illness.

Most important, emotions are responsive to a wide range of events. From a psychometric perspective, emotions are poor indicators of disease states; they may be sensitive indicators of illness, but they are nonspecific. Thus, if one is actively connected to one’s social world, one will feel emotions of joy and distress, and distress may indicate the presence of chronic, life-threatening illness in elderly spouses, family members, and friends, and not just oneself.

Because being connected enhances survival, distress caused by illness in a spouse or family member may be positively associated with function and good health. Because they are nonspecific, measures of emotional traits and states are poor predictors of health-relevant behaviors; for example, generalized anxiety is a poor predictor of management of diabetes complications.

Prediction of self-management behaviors improves when affect is assessed in association with specific perceptions; for example, a fear of hypoglycemia predicts poor adherence to the use of insulin and elevated blood glucose, and fear of foot amputation predicts efforts at effective selfmanagement.

In short, an examination of the implications of emotion for physical health agrees with functional and neurobiological analyses in pointing to the interaction and integration of emotional process with perception, cognition, and contextualized action.