WASHINGTON — A major study of 108,915 adult women in Iceland and the United Kingdom found a dose-response link between adverse childhood experiences and autoimmune disease risk, according to research published in Psychological Medicine, April 20, 2026. Researchers said symptoms of depression, anxiety and post-traumatic stress appeared to explain about one-quarter of the association, pointing to mental distress as one possible pathway rather than a single proven cause.
The findings add to a growing body of research suggesting that severe or repeated stress may leave biological traces that matter for immune health. They also arrive as women remain disproportionately affected by autoimmune conditions, a broad group of diseases in which the immune system mistakenly attacks the body’s own tissues.
Autoimmune disease risk and the stress signal
The new paper drew on the Icelandic Stress-And-Gene-Analysis cohort, known as SAGA, and the UK Biobank. Together, the cohorts included 22,423 women in Iceland and 86,492 women in the United Kingdom. Participants reported adverse childhood experiences, and researchers compared those histories with autoimmune diseases that were self-reported in SAGA and identified through hospital records in the UK Biobank.
Researchers found that each additional adverse childhood experience was linked with a 10% higher prevalence ratio for any studied autoimmune disease. The association was especially noted for conditions including Sjögren’s disease, polymyalgia rheumatica, rheumatoid arthritis, systemic lupus erythematosus and thyroid disease. The study also found that sexual abuse and physical and emotional neglect were consistently associated with higher autoimmune disease prevalence when the researchers considered several forms of childhood adversity together.
The paper does not show that stress alone causes autoimmune disease. Autoimmune disorders are complex and can involve genetics, hormones, infections, environmental exposures and other factors. But the study strengthens the case that traumatic stress and later mental distress deserve more attention in autoimmune research and clinical care.
Why women carry the heavier burden
Women are central to the autoimmune disease discussion because they make up most diagnosed patients. The National Institutes of Health says up to 50 million people in the United States live with an autoimmune disease, and four of every five people diagnosed are female.
That imbalance is not explained by stress alone. A Stanford Medicine report on research published in Cell pointed to Xist, a molecule involved in X-chromosome inactivation, as one possible contributor to female-biased autoimmunity. Howard Chang, the study’s senior author and a Stanford physician-scientist, said of lupus and scleroderma patients, “The great majority of these patients are women.”
That biology matters because it helps prevent a harmful oversimplification: Women are not developing autoimmune diseases because they failed to manage stress well enough. Instead, the emerging picture suggests that stress-related pathways may interact with sex-linked biology and other established risk factors.
Earlier studies show a long-running pattern
The new findings build on research that has been developing for years. In 2009, researchers using data from the Adverse Childhood Experiences Study reported that each increase in ACE score was associated with a higher likelihood of hospitalization for autoimmune disease decades later.
In 2015, a Veterans Affairs research brief reported that Iraq and Afghanistan veterans with PTSD had a significantly higher risk of autoimmune disorder diagnoses, while women veterans had almost three times the prevalence of autoimmune disorders overall. The VA summary cautioned that the study could not prove causation.
A larger 2018 Swedish register study later followed 106,464 people with stress-related disorders, more than 1 million matched unexposed people and 126,652 full siblings. The JAMA study found that people diagnosed with stress-related disorders had a higher subsequent risk of autoimmune disease than comparison groups.
Newer evidence is stronger, but still cautious
Recent work continues to support a stress-autoimmunity link, while also emphasizing uncertainty. A 2025 systematic review and meta-analysis in Brain, Behavior, and Immunity found a small but significant association between childhood adversity and autoimmune disease in adulthood. The authors cautioned that the evidence was highly variable and that many studies carried a high risk of bias.
Another 2025 case-control study in Clinical and Experimental Rheumatology examined stressful life events in the year before systemic autoimmune rheumatic disease diagnosis. Researchers found that people with those diseases reported more total, uncontrollable, undesirable and highly stressful events than unrelated controls, although sibling comparisons were less definitive.
What patients and clinicians can take from the findings
The clearest message is not that stress reduction can prevent autoimmune disease by itself. The more practical takeaway is that trauma history and mental health symptoms may be relevant to autoimmune risk, diagnosis and long-term care, especially for women.
Researchers said the findings support greater clinical awareness of depression, anxiety and post-traumatic stress symptoms among people with adverse childhood experiences. For patients, the results should not be read as blame. They are a reminder that immune health and mental health can be connected, and that persistent symptoms deserve medical attention rather than self-diagnosis or dismissal.
As autoimmune diseases continue to affect millions of people and women carry much of the burden, the stress link is becoming harder to ignore. The science is not simple, but it increasingly suggests that the body’s immune system may remember more than genetics alone.
