Past studies have shown that there appears to be a correlation between chronic depression and the likelihood of dementia in the later years. Likewise, there are studies which indicate that inflammatory changes in the brain are pathological features of both depression and dementia. These findings have caused rheumatologists to forever be looking over their shoulders: Does the inflammation of the inflammatory diseases rheumatologists treat play a role in depression (and for that matter, dementia)? Perhaps the dysphoria experienced by so many patients with chronic illness is not due simply to the condition of being burdened with a chronic illness, but precipitated by the physiological processes which caused the disease itself.
It may not be all in your head. At least some of "it" may be in your body.
The task at hand is to fully understand this relationship between inflammation and depression; and from there, the way might open up for improved management of those suffering from inflammatory illnesses.
Recently, a Japanese team's findings on this subject were published in the journal, "Psychosomatic Medicine". Over 200 patients with rheumatoid arthritis were studied. They found that C-reactive protein (CRP), a marker of inflammation, was associated with elevated depression and pain scores; inflammation and depression were found to have an independent effect on patient-reported pain.
It appears that the relationship between inflammation and pain and depression is a complex one: Central and peripheral nervous system pain processing, hypothalamic-pituitary-adrenal interactions, and psychosocial factors all have important roles in the psychological response to inflammation. Rheumatologists may find themselves addressing these complex interactions as part of the clinical care given their patients.
Many patients have continued disability, even after the use of the potent immune-suppressing drugs used to treat illnesses such as rheumatoid arthritis. Researchers will have to isolate and target the inflammatory mediators of depression, and not just those thought to cause swollen and painful joints. And clinicians will require the skills and empathy to recognize depression, as a study published in "Biological Psychiatry" last year found that there was actually a decrease in inflammation in depressed patients treated with anti-depressants.
Inflammation, pain and depression are a part of the tangled web in which so many patients are trapped. Let's hope further research can untangle some of the mysteries of that inscrutable mind-body nexus.