Physical Health: Body and Brain
From infancy through adolescence, the body’s biology develops. Normal biological function is partly determined by environment. When a child grows up afraid or under constant or extreme stress, the immune system and body’s stress response systems may not develop normally. Later on, when the child or adult is exposed to even ordinary levels of stress, these systems may automatically respond as if the individual is under extreme stress. For example, an individual may experience significant physiological reactivity such as rapid breathing or heart pounding, or may “shut down” entirely when presented with stressful situations. These responses, while adaptive when faced with a significant threat, are out of proportion in the context of normal stress and are often perceived by others as “overreacting” or as unresponsive or detached.