In a study of more than 666,000 Veterans of Iraq and Afghanistan, those with PTSD were more likely to have autoimmune disorders such as rheumatoid arthritis, multiple sclerosis, lupus, inflammation of the thyroid, and inflammatory bowel disease.
The study, led by Dr. Aoife O'Donovan at the San Francisco VA Medical Center, found a twofold
increased risk among those with PTSD, compared with those who had no psychiatric diagnoses.
When the Veterans with PTSD were compared against those with other psychiatric disorders, the risk of autoimmune disease among the PTSD group was still greater—by 51 percent.
The new findings jibe with those from smaller studies.
The reasons for the linkage are unclear. O'Donovan's group says it could have to do with immune or hormonal changes brought about by PTSD. Or, it could be due to health habits that are more common in those with PTSD, such as smoking, drinking, poor diet, or impaired sleep. A third theory is that pre-existing genetic or environmental risk factors might lay the groundwork for both conditions.
In any event, the study doesn't show that PTSD causes autoimmune disease—only that there's a relationship.
The study adds to others showing a link between PTSD and various physical conditions, including heart disease.
"Our findings...contribute to the growing literature highlighting the increased risk for other chronic physical diseases in veterans with PTSD and other psychiatric disorders," wrote the authors. (Biological Psychiatry, online June 28, 2014)