Nature
Shame covers the broad spectrum of painful affects, including the the emotional consequences embarrassment, humiliation, mortification and disgrace, that accompany the feeling of being rejected, ridiculed, exposed, or of losing the respect of others. Shame results when people receive negative messages -- either internally or from others, leading them to believe they are a bad or defective person who is helpless to change that deficit. Physical sickness (eg queasiness) and feelings of helplessness and powerlessness often accompany shame. Through the link with stress, shame may impact the human immune system and play a part in the disease process.
Incidence
Researchers at the University of California, Los Angeles (UCLA) demonstrated the vicious cycle of shame and illness by enrolling a group of graduate students into a study to examine how their opinions of themselves affect their immune systems. They asked students to write about traumatic or emotional experiences for which they blamed themselves; others were asked to write about experiences that didn't evoke any guilt or shame. Participants who wrote about neutral experiences and those who felt guilt over their experience showed no measurable physical changes that might make them ill. However, the students who felt shame for the incidents they wrote about showed an increase in cytokine activity, as measured by blood tests. (Cytokines are chemicals that signal inflammation, indicating that a disease process may be in progress.) The people who felt the most shame had the highest elevation of cytokine activity.