The time dimension in stress responses: relevance for survival and health

Within the Cognitive Activation Theory of Stress (CATS), the stress respons e occurs whenever there is a discrepancy between what the organism is expec ting, and what really exists. It affects the biochemistry of the brain, mob ilizes resources, affects performance, and endocrine, vegetative, and immun e systems. Initial positive feedback and feed-forward mechanisms are gradua lly changed by homeostatic mechanisms. Slower reactive hormones such as cor tisol seem to dampen the initial response. The time course may depend on ps ychological mechanisms. Subjects with efficient coping show the fast- and s hort-lasting catecholamine response, while subjects with high defense mecha nisms (related to stimulus expectancies) may show more signs of prolonged a ctivation. Non-coping individuals show a sustained general activation which may develop into somatic disease or illness. (C) 1999 Elsevier Science Ire land Ltd. All rights reserved.