In recent years, researchers have learned more and more about how stress and psychological trauma can effect the brain and overall health. Now, a new study has found evidence that traumatic events in childhood and stress or emotional instability at any period in life are associated with later development of chronic fatigue syndrome (CFS).

The findings suggest that CFS and similar illnesses may result from the brain's inability to cope with some experiences.

CFS affects between 400,000 and 900,000 U.S. adults. The condition is defined as unexplained fatigue that lasts for at least six months, does not get better with rest and interferes with daily activities. Additional symptoms include extreme fatigue after exertion, difficulties with memory and concentration, unrefreshing sleep, headaches, muscle pain, joint pain, sore throat and tender lymph nodes. "Despite the substantial public burden of CFS, the causes and pathophysiology [underlying changes] of CFS remain unknown, and effective prevention is elusive," write the study authors in the November issue of Archives of General Psychiatry.

Christine Heim, Ph.D., of the Centers for Disease Control and Prevention and Emory University, Atlanta, and colleagues compared 43 individuals with CFS to 60 controls without CFS who were all part of a large study of Wichita, Kansas, residents. All participants responded to a questionnaire that assessed for five types of childhood trauma: emotional, physical and sexual abuse and emotional and physical neglect. Responses to each item were numbered and added to produce a score for each type of trauma and one overall trauma score.

Individuals with CFS had higher overall trauma scores than those without CFS. Exposure to trauma increased the risk of CFS between three and eight times, depending on the type; emotional neglect and sexual abuse during childhood were most strongly associated with CFS. For each additional type of childhood trauma experienced, the risk of having CFS increased by 77 percent; the risk increased by 6 percent for each additional point increase in total trauma score. Not all patients with CFS had experienced childhood trauma but those who had tended to have worse symptoms than those who had not.

CFS patients were also more likely than controls to have psychiatric disorders, including depression, anxiety and post-traumatic stress disorder. These conditions appear to be associated with childhood trauma. "In sum, it appears that CFS is part of a spectrum of disorders that are associated with childhood adversity," the authors write. "In adulthood, these disorders frequently manifest or worsen in relation to an acute stress or challenge."