by Life with an autoimmune disease can almost double the risk of mental illnesses such as depression, anxiety and bipolar disorders, according to a study.
The link can be explained by chronic exposure to systemic inflammation caused by the autoimmune disease, explained researchers from the University of Edinburgh.
A growing number of evidence suggests that inflammation is associated with a mental illness, but many of the published studies have based on small sample sizes, which restricted their statistical power.
In order to overcome this, the researchers based data from 1.5 million people in our future health program from all over the UK. The participants filled out a questionnaire that asked for personal, social, demographic, health and lifestyle formations.
The health information included lifelong diagnoses for disorders, including autoimmune and psychiatric diseases. Six autoimmune diseases were included in the study: rheumatoid arthritis, grave disease (thyroid hormone disorder), inflammatory bowel disease, lupus, multiple sclerosis and psoriasis.
The mental illnesses in which the researchers were interested were self -reported diagnoses of affective disorders that were defined as depression, bipolar or anxiety disorder.
A total of 37,808 people did not report autoimmune conditions and 1,525,347. The life prevalence of a diagnosed affective disorder was significantly higher in patients with an autoimmune disease than in the general population: 29% against 18%.
Similar associations arose for depression and anxiety: 25.5% compared to just more than 15% in depression and a little more than 21% compared to 12.5% for anxiety. The prevalence of current depression and fear was also higher in people with autoimmune diseases.
While the prevalence of bipolar disorder was much lower, it was still significantly higher in patients with autoimmune diseases than in the general population: almost 1% compared to 0.5%.
The prevalence of affective disorders was also significant in women with autoimmune diseases and consistently higher than in men with the same physical illnesses: 32% compared to 21%.
The reasons for this are unclear. The researchers, the results of which were published in the BMJ Mental Health Journal, indicate that sex hormones, chromosomal factors and differences in the circulating antibodies can partially explain the differences.
Overall, the risk of mental illness in people with autoimmune diseases was almost twice as high as between 87% and 97% higher. It remained even after adaptation to potentially influential factors, including age, household income and psychiatric parents’ history.
The study was limited by a lack of available information about the time or duration of the disease, which made it impossible to determine whether the autoimmunes have preceded conditions that were summarized or followed with affective illnesses.
No direct measurements of the inflammation were also carried out, which made it impossible to determine the presence, the type, time or the severity of the inflammation.
The researchers came to the conclusion: “Although the observation design of this study does not allow direct inference of causal mechanisms, this analysis of a large national data record suggests that chronic exposure to systemic inflammation can be associated with a higher risk of affective disorders.
“Future studies should try to determine whether alleged biological, psychological and social factors – for example chronic pain, fatigue, sleep or circadian disorders and social isolation – can potentially change mechanisms that combine autoimmune conditions and affective disorders.”
They added that it could be worthwhile to regularly examine people in whom autoimmune diseases for mental illnesses, especially women, were diagnosed to provide them with tailor -made support at an early stage.
