Living with an autoimmune disease can almost double the risk of mental health problems, including depression, anxiety and bipolar disorder, suggests a study.
The link can be explained by chronic exposure to the systemic inflammation that autoimmune disease causes, said researchers from the University of Edinburgh.
An increasing number of evidence suggest that inflammation is linked to poor mental health, but many published studies have relied on a small sample size, limiting their statistical power.
To overcome this, researchers relied on data of 1.5 million people in our future Health Program from all over the United Kingdom. Participants fulfilled a questionnaire that requested personal, social, demographic, health and lifestyle information.
Health information included life diagnostics for disorders, including autoimmune and psychiatric conditions. Six autoimmune conditions were included in the study: rheumatoid arthritis, tombs disease (thyroid hormonal disorder), inflammatory intestine disease, lupus, multiple sclerosis and psoriasis.
The mental health problems that interested them were self -depressed diagnoses of emotional disorders, defined as depression, bipolar or anxious disorder.
In total, 37,808 people declared autoimmune conditions and 1,525,347 did not do so. The life prevalence of any diagnosed affective disorder was significantly higher in people with an autoimmune disorder than among the general population: 29% against 18%.
Similar associations have emerged for depression and anxiety: 25.5% compared to just over 15% for depression, and just over 21% against 12.5% for anxiety. The prevalence of current depression and anxiety was also higher in people with autoimmune conditions.
Although the prevalence of bipolar disorder is much lower, it was still significantly higher in autoimmune disorders than among the general population: just under 1% against 0.5%.
The prevalence of emotional disorders was also significantly and systematically higher in women with autoimmune disorders than among men suffering from the same physical health conditions: 32% compared to 21%.
The reasons for this are not clear. But researchers, whose results were published in the BMJ Mental Health Journal, said that theories suggest that sex hormones, chromosomal factors and differences in circulating antibodies can partly explain the differences.
Overall, the risk of mental health problems was almost double in people with autoimmune conditions – between 87% and 97% more. It remained high even after adjustment for potentially influential factors, including age, household income and parental psychiatric history.
The study was limited by a lack of information available on the time or duration of the disease, which makes it impossible to determine whether the previous autoimmune conditions, co-in with emotional or followed disorders.
No direct measure of inflammation was done either, which makes it impossible to establish the presence, nature, the moment or severity of inflammation.
Researchers have concluded: “Although the conception of observation of this study does not allow direct inference of causal mechanisms, this analysis of an important national data set suggests that chronic exposure to systemic inflammation can be linked to a higher risk of affective disorders.
“Future studies should seek to determine whether the biological, psychological, psychological and social factor factors – for example, chronic pain, fatigue, sleep or circadian disturbances and social isolation – can represent potentially modifiable mechanisms connecting autoimmune and affective conditions.”
They added that it could be worth the sentence to regularly detect people diagnosed with autoimmune diseases for mental health problems, especially women, to provide them with tailor-made support from the start.