Drugs that are used to treat a number of autoimmune diseases appear to treat symptoms of depression as well. The finding of a new study suggests that anti-inflammatories, as they are known, may take their place alongside conventional treatments to help people with depression.
An analysis of a number of drug studies involving people with autoimmune diseases, including psoriasis, rheumatoid arthritis and Crohn’s disease, found that participants with symptoms of depression were improved after the research ended.
Inflammation is culprit
In autoimmune diseases, white blood cells become overactive, and instead of attacking bacteria and viruses, the immune system assaults various tissues in the body.
Anti-inflammatory drugs quiet the immune system by disarming cytokines, a protein that is a major player in the body’s inflammatory response.
A small amount of inflammation is necessary to activate the immune system to fight microbes. But Golam Khandaker, professor of psychiatry at the University of Cambridge in England, says too much inflammation is harmful.
“Slow burning inflammation that’s burning in our body can cause a number of physical and psychiatric conditions,” he explained, pointing to a couple of examples. “In the brain, it could lead to increased risks of depression. Similarly, in the body, it could lead to increased risk of heart disease, coronary heart disease such as stroke … or Type 1 diabetes or Type 2 diabetes.”
Frequently, people with autoimmune diseases, which include Type 1 diabetes, suffer from depression. It’s thought that they are depressed because of their chronic illnesses. But the new study suggests that inflammation alters brain chemistry, causing the psychiatric disorder.
Unlike anti-inflammatory drugs, antidepressants work by restoring the proper function of brain chemicals called neurotransmitters. However, a significant number of people with depression do not respond to psychiatric medicine.
For the meta-analysis, published in the Nature journal Molecular Psychiatry, Khandaker and colleagues looked at the results of 20 studies of people treated with anti-cytokine — or anti-inflammatory — drugs for their arthritis, psoriasis and Crohn’s disease.
They found that individuals who reported symptoms of hard-to-treat depression before the study had a mild to moderate reduction in those symptoms afterward, similar to the effectiveness of antidepressants.
“And what they showed is that patients who were inflamed — in other words, they had elevated levels of inflammatory markers at the beginning of the trial — so these patients showed benefits from the anti-cytokine drug,” Khandaker said. “And the higher the level of inflammation, the greater the improvement in the severity of depressive symptoms.”
Psychiatry has been called an art rather than a science because there are no tests to tell doctors which antidepressants will be effective in patients.
The finding that anti-inflammatory drugs may ease depressive symptoms could someday lead to the use of a blood test for inflammation in people who suffer from depression. And anti-cytokine drugs could someday be used in patients with depression when other drugs have failed.