Childhood trauma, including sexual abuse, emotional abuse and emotional neglect, was linked to a six-fold risk increase for chronic fatigue syndrome in adults, in a study published in the Archives of General Psychiatry.
"Stress in interaction with other risk factors likely triggers chronic fatigue syndrome symptoms through its effects on central nervous, neuroendocrine and immune systems," the study's authors said.
About 2.5 percent of adults in the United States are affected by chronic fatigue syndrome, about which little is known regarding its causes and how the condition develops.
"However, obviously not every individual exposed to a stressor goes on to develop chronic fatigue syndrome, and it is therefore of critical importance to understand sources of individual differences in vulnerability to the pathogenic effects of stress," said Christine Heim, of Emory University School of Medicine, Atlanta, Georgia.
The researchers studied 113 chronic fatigue patients and 124 healthy individuals who served as controls.
Drawn from a general sample of 19,381 adults, study participants reported whether they had experienced childhood trauma, including sexual, physical and emotional abuse or emotional and physical neglect.
They also were screened for depression, anxiety and post-traumatic stress disorder and were tested for levels of the hormone cortisol in their saliva - low levels may indicate decreased function of the body's main neuroendocrine stress response system.
Individuals with chronic fatigue syndrome reported higher levels of childhood trauma exposure, the researchers said.
Exposure to childhood trauma was associated with a six-fold increase in the risk of having chronic fatigue syndrome, they added.
Sexual abuse, emotional abuse and emotional neglect were most closely associated with chronic fatigue syndrome. Patients with the syndrome also were more likely than controls to have depression, anxiety and post-traumatic stress disorder, they said.
Cortisol levels were decreased in patients with chronic fatigue syndrome who experienced childhood trauma, but not in those with chronic fatigue syndrome who had not been subjected to trauma.
"Our results confirm childhood trauma as an important risk factor of chronic fatigue syndrome," the study authors write.
"Our findings are critical to inform pathophysiological research and to devise targets for the prevention of chronic fatigue syndrome," they added.
The research was supported by the federal Centers for Disease Control and Prevention (CDC).