Socioeconomic status and health: a neurobiological perspective

Socioeconomic status (SES) is one of the strongest predictors of health in industrial nations. This is especially true of societies with large disparities between rich and poor. Evidence suggests that the interactions between individuals of different SES play a crucial role in mediating the effects of SES on health. The question is why? Because humans are extremely social animals, their sense of well being is to a large extent determined by their social interactions. In hierarchical societies, individuals at every level of the hierarchy have to submit to those above and the recognition of this submissiveness generates emotions such as shame, anger and depression. These emotions lead to the activation of physiological alarm systems such as the hypothalamic pituitary adrenal axis and the sympathetic nervous system. The chronic activation of these systems alter their set points. This results in changes in the systems' different target organs responsible for diseases such as adult onset diabetes, hypertension, atherosclerosis, major depression and autoimmune diseases. Recent evidence from neurobiology show that one brain area, the amygdala, plays a pivotal role in processing social emotions. Anatomical and physiological studies of the amygdala in animals show how this area could play the central role in activating the alarm systems. This recent evidence brings a deeper level of plausibility to the postulated mechanisms of activation of the alarm systems by social emotions. Other experimental evidence also shed more light on the pathways responsible for translating psychosocial experiences into physiological perturbations.