- Chronic inflammation and depression may be linked, says a new study.
- People with autoimmune conditions are twice as likely to experience depression.
- This study points out the importance of depression screening in those with autoimmunity.
A recent large-scale study conducted by researchers at the University of Edinburgh sheds light on the link between chronic inflammation and depression, as well as other affective disorders such as bipolar disorder and anxiety.
Analyzing data from more than 1.5 million adults in the UK, the study, which was published on June 24, 2025, in BMJ Mental Health, found that people living with chronic inflammatory conditions, specifically autoimmune diseases, are nearly twice as likely to experience depression and other affective disorders compared to the general population.
This finding offers compelling evidence that individuals living with autoimmune diseases face a significantly higher risk of experiencing mental health challenges.
Understanding how chronic inflammation and depression are linked
Autoimmune conditions are characterized by chronic inflammation caused by the body’s immune system mistakenly attacking its own tissues.
Scientists have long suspected that this ongoing inflammation might influence brain function and mental health.
To learn more about how chronic inflammation and depression are connected, the researchers analyzed data from the Our Future Health (OFH) research cohort, one of the largest health-related research projects globally, which aims to recruit 5 million adults across the UK.
As of early 2025, OFH had enrolled over 1.5 million participants, gathering extensive information through online questionnaires and in-person clinical visits.
Participants were adults aged 18 and over, recruited via postal invitations and online volunteering.
They provided self-reported health information, including lifetime diagnoses of both autoimmune conditions and psychiatric disorders such as depression, bipolar disorder, and anxiety.
The autoimmune conditions studied included rheumatoid arthritis, Graves’ disease, inflammatory bowel disease, lupus, multiple sclerosis, and psoriasis.
While the study did not examine celiac disease specifically, some researchers suggest that gluten intolerance could be another pathway linking chronic inflammation and depression.
Similarly, Hashimoto’s thyroiditis—an autoimmune cause of hypothyroidism—may also represent a connection between chronic inflammation and depression.
In addition to lifetime diagnoses, participants completed standardized screening questionnaires for current depressive and anxiety symptoms—the Patient Health Questionnaire (PHQ-9) and the Generalized Anxiety Disorder Scale (GAD-7).
Scores of ≥10 on the PHQ-9 indicated current depression, while scores of ≥8 on the GAD-7 indicated current anxiety.
Researchers compared two groups: 37,808 individuals with self-reported autoimmune conditions and 1,525,347 without.
Statistical analyses included prevalence calculations and logistic regression models to estimate the odds of having affective disorders among those with autoimmune diseases, adjusting for factors such as age, sex, ethnicity, household income, parental history of affective disorders, chronic pain, and social isolation.
People with autoimmune conditions had a greater risk of depression and anxiety
The study found that the lifetime prevalence of any affective disorder—depression, bipolar disorder, or anxiety—was significantly higher among people with autoimmune conditions, at 28.8%, compared with 17.9% in the general population.
Breaking it down, lifetime prevalence of depression was 25.5% in the autoimmune group versus 15.2% in others; anxiety was 21.2% versus 12.5%; and bipolar disorder, though less common overall, was nearly twice as prevalent at 0.9% versus 0.5%.
Current symptoms of depression and anxiety were also more common in people with autoimmune diseases. Nearly 19% of those with autoimmune conditions screened positive for current depression compared to 10.5% of others. Similarly, 20% showed current anxiety symptoms versus 12.9% in the general population.
Importantly, women with autoimmune conditions had even higher rates of affective disorders than men with the same physical health conditions. For example, 31.6% of women with autoimmune diseases reported lifetime affective disorders compared to 20.7% of men with autoimmune diseases.
After adjusting for various sociodemographic and health-related factors, people with autoimmune conditions still had approximately 1.5 times higher odds of experiencing any affective disorder, including depression, bipolar disorder, and anxiety. The odds for current depression were even higher, at about 1.7 times greater risk.
Why the link between chronic inflammation and depression matters
Though the study design does not prove causation, these findings strongly suggest that chronic systemic inflammation—characteristic of autoimmune diseases—may contribute to an increased risk of depression and other mood disorders.
Chronic inflammation can affect brain function and mood regulation through complex biological pathways.
The large sample size and representative nature of the cohort strengthen the reliability and generalizability of the findings within the UK.
However, limitations include reliance on self-reported diagnoses and lack of direct inflammatory biomarker measurements.
Future research with longitudinal designs and biomarker data will be essential to clarify causal relationships.
Clinically, the study underscores the importance of routinely screening for mental health issues in people with autoimmune diseases, particularly women, to enable early intervention.
Integrating mental health support with physical healthcare for chronic inflammatory conditions could improve overall patient outcomes.
This research adds to a growing body of evidence highlighting the interconnectedness of physical and mental health and the association between chronic inflammation and depression.
Takeaway
This groundbreaking study highlights how chronic inflammation, especially in autoimmune diseases, is strongly linked not only to depression but also to anxiety and other affective disorders.
Recognizing the powerful connection between chronic inflammation and depression underscores the need for integrated care approaches that address both physical and psychological well-being.
For individuals living with autoimmune conditions, early screening and treatment for anxiety and depression could significantly improve quality of life and overall health outcomes.
Image credit: Vilius Kukanauskas from Pixabay
Nancy Schimelpfening is the founder of Depression Sanctuary. Unless otherwise stated, all of the content on Depression Sanctuary is written by and maintained by Nancy. Nancy has a master’s degree in community health education from Old Dominion University in Norfolk, VA. She was the About.com (now Verywell.com) expert on depression from 1998-2016. She has also written for other online publications, including Healthline, Healthgrades Professional, Health Digest, and MindBodyGreen.
