Background: The lack of standardized criteria for defining chronic fatigue syndrome (CFS) has constrained research. The objective of this study was to apply the 1994 CFS criteria by standardized reproducible criteria.

Sensitization of stress-responsive neurobiological systems as a possible consequence of early adverse experience has been implicated in the pathophysiology of mood and anxiety disorders. In addition to early adversities, adulthood stressors are also known to precipitate the manifestation of these disorders. The present study sought to evaluate the relative role of early adverse experience vs. stress experiences in adulthood in the prediction of neuroendocrine stress reactivity in women. A total of 49 women (normal volunteers, depressed patients, and women with a history of early abuse) underwent a battery of interviews and completed dimensional rating scales on stress experiences and psychopathology, and were subsequently exposed to a standardized psychosocial laboratory stressor. Outcome measures were plasma adrenocorticotropin (ACTH) and cortisol responses to the stress test. Multiple linear regression analyses were performed to identify the impact of demographic variables, childhood abuse, adulthood trauma, major life events in the past year, and daily hassles in the past month, as well as psychopathology on hormonal stress responsiveness. Peak ACTH responses to psychosocial stress were predicted by a history of childhood abuse, the number of separate abuse events, the number of adulthood traumas, and the severity of depression. Similar predictors were identified for peak cortisol responses. Although abused women reported more severe negative life events in adulthood than controls, life events did not affect neuroendocrine reactivity. The regression model explained 35% of the variance of ACTH responses. The interaction of childhood abuse and adulthood trauma was the most powerful predictor of ACTH responsiveness. Our findings suggest that a history of childhood abuse per se is related to increased neuroendocrine stress reactivity, which is further enhanced when additional trauma is experienced in adulthood.

These results suggest that specific personality traits may constitute markers of vulnerability to the development of psychopathological symptoms after trauma exposure. Early identification of preexisting risk factors is needed to provide effective prevention and intervention for individuals who are at risk of developing trauma-related disorders.

The high prevalence of PTSD and other psychiatric impairments in firefighters indicates that they often fail to cope with primary and particularly secondary stress in their daily work. This problem, together with the individual psychological consequences and expenses related to work absenteeism and early retirement, seems to be very specific for the profession of firefighters. The present findings provide a better understanding of the relationship between secondary traumatic stress and PTSD in professional helpers and high-risk populations such as firefighters, emergency workers, and the police.

This study provides evidence of increased levels of multiple types of childhood trauma in a population-based sample of clinically confirmed CFS cases compared with nonfatigued controls. Our results suggest that childhood trauma is an important risk factor for CFS. This risk was in part associated with altered emotional state. Studies scrutinizing the psychological and neurobiological mechanisms that translate childhood adversity into CFS risk may provide direct targets for the early prevention of CFS.