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We present an integrative model of disease mechanisms in the Chronic Fatigue Syndrome (CFS), unifying empirical findings from different research traditions. Based upon the Cognitive activation theory of stress (CATS), we argue that new data on cardiovascular and thermoregulatory regulation indicate a state of permanent arousal responses - sustained arousal - in this condition.
We suggest that sustained arousal can originate from different precipitating factors (infections, psychosocial challenges) interacting with predisposing factors (genetic traits, personality) and learned expectancies (classical and operant conditioning).
Furthermore, sustained arousal may explain documented alterations by establishing vicious circles within immunology (Th2 (humoral) vs Th1 (cellular) predominance), endocrinology (attenuated HPA axis), skeletal muscle function (attenuated cortical activation, increased oxidative stress) and cognition (impaired memory and information processing).
Finally, we propose a causal link between sustained arousal and the experience of fatigue. The model of sustained arousal embraces all main findings concerning CFS disease mechanisms within one theoretical framework.
Source: Behavioral and Brain Functions – Feb 23, 2009;5(1):10. PMID: 19236717, by Wyller VB, Eriksen HR, Malterud K. Division of Pediatrics, Rikshospitalet University Hospital, Oslo; Department of Education and Health Promotion, University of Bergen; Research Unit for General Practice, Unifob Health Bergen, Norway. [E-mail: