Stress, emotions and health: where do we stand?

Our representation of the way stress influences the development and progres sion of disease has been shaped by physiological stress theories. According to these theories, the organism's reaction to any stimulus that threatens its homeostasis is stereotyped and involves both the sympathetic medullary adrenal axis and the pituitary-adrenal axis. These systems ran overtax the organism's resistance, especially when they are chronically activated. Howe ver, physiological stress responses are not stereotyped They depend qualita tively and quantitatively on the psychological dimensions of the situation, including the subject's ability to predict and control the occurrence of s tressors. Studies of the effects of stress and emotions and immunity have c onfirmed the importance of predictability and controllability. In addition, they have made clear that if stress and emotions can influence emotions, r eciprocally immune factors have profound influences on mood and behaviour T hese reciprocal relationships between the brain and the immune system ave m ediated by an intricate network of neural and molecular connections. Becaus e of this reciprocity, it is difficult if not impossible to isolate one ter m of the relationship and claim it is causally related to the other one. Th is explains why the field has moved away from the consideration of the role of psychosocial factors and emotions in the pathogeny of somatic diseases to more pragmatic questions such as the way patients cope with their diseas e and the medical system.