Researchers from Hadassah, the Hebrew University, Sheba, and partner institutions found a consistent association between chronic PTSD and several categories of newly diagnosed autoimmune disorders.
An Israeli-led study involving more than 316,000 matched individuals has found that people diagnosed with chronic post-traumatic stress disorder had a higher risk of developing an autoimmune disease during follow-up.
The research was published online on August 11, 2026, in Brain, Behavior, and Immunity.
The study was conducted by researchers affiliated with Hadassah Medical Center, the Hebrew University of Jerusalem, Sheba Medical Center, Tel Aviv University, and Reichman University.
Using the international TriNetX health-record network, the team examined whether the association seen in earlier observational studies remained consistent across a large population and multiple types of autoimmune disease.
The scale of the findings
The researchers matched people with newly diagnosed chronic PTSD and no autoimmune disease at baseline to similar individuals without PTSD.
Matching included age, sex, race, ethnicity, obesity, smoking, and psychiatric comorbidities.
The final matched cohort included 316,482 people, with an average age of 38.5 years. Approximately 64.1% were women.
Across more than one million person-years of follow-up, a new autoimmune disorder was diagnosed in 8.4% of individuals with PTSD and 6.5% of those without PTSD.
This corresponded to a hazard ratio of 1.34—a 34% higher relative risk—with an estimated absolute risk difference of 2.9 percentage points over four years.
Higher risks were observed across several categories of autoimmune disease:
- rheumatologic;
- gastrointestinal;
- hematologic;
- endocrine;
- neurological.
The association remained present in men and women, across age and racial or ethnic subgroups, and among people both with and without depression or anxiety.
Association does not prove causation
The study does not show that PTSD directly causes autoimmune disease.
It was retrospective and relied on electronic health records, which may contain incomplete diagnoses or unmeasured differences between groups.
Factors such as healthcare utilization, medication exposure, infection history, sleep disturbance, socioeconomic conditions, and chronic inflammation could contribute to the observed association.
Even so, the size and consistency of the findings strengthen the case for viewing PTSD as a condition with potential effects beyond mental health.
Stress-related changes in the nervous, hormonal, and immune systems represent biologically plausible pathways, but the mechanisms require further study.
For clinicians, the results do not justify broad laboratory screening in every person with PTSD.
They do support careful attention to persistent symptoms such as unexplained joint pain, rashes, digestive problems, neurological changes, or unusual fatigue, as well as timely evaluation when clinically indicated.
Equally important, people with PTSD should not assume that they will develop an autoimmune disorder. The increase in risk was measurable but far from inevitable.
Sapir Medical Clinic can coordinate specialist evaluations and second opinions in Israel for patients with complex or unexplained symptoms, including access to rheumatology, neurology, endocrinology, gastroenterology, and immunology expertise.
If you would like to receive medical treatment in Israel using the most advanced technologies and latest innovations, with leading doctors at Israel’s top hospitals, contact Sapir Medical Clinic: info@sapirmedical.com