Stress is known to cause physiological changes, including changes in immune function, but evidence that links it to specific diseases is limited.
This study, in JAMA, used a Swedish database of 106 464 patients who had a severe stress condition, such as post-traumatic stress disorder (PTSD), acute stress reaction or adjustment disorder. They compared them with 1 064 640 people free of stress-related disorders and with 126 652 of their stress-free siblings.
During an average 10 years of follow-up, there were 8 284 cases of autoimmune disease among those diagnosed with a stress disorder; 57 711 among those without one, and 8 151 among the unstressed siblings.
After controlling for other risk factors, they found that compared with those who had not had severe stress, those with any stress-related disorder were 36 percent more likely to have an autoimmune disease, and 29 percent more likely than their unstressed siblings. People with a PTSD diagnosis were at especially high risk — they were 46 percent more likely to develop an autoimmune illness.
“Stress really affects long-term health,” said the lead author, Dr. Huan Song, a postdoctoral fellow at the University of Iceland. “It affects not only psychiatric health, but leaves people vulnerable to other diseases. There are many treatments now available for stress-related disorders, and it’s important for people to get treatment early,” he said.