Inflammation and Depression Combine to form Cycle

Depression can be worsened with inflammation, according to findings published in the American Journal of Psychiatry.

Researchers from Rice University reviewed 200 studies linking depression and inflammation to determine what the results are from the symptoms coexisting in a patient.

The researchers found that treatment decisions might be informed by attention to questions of the pathways and predispositions that these two symptoms are connected. Combined with factors like childhood adversity, obesity, stressors, and pathogens, depression and inflammation can feed the cycle and result in more depression and inflammation.

Inflammation was linked to depression and other mental health issues, cancer, and diabetes. Patients involved in each of the studies demonstrated elevated levels of the inflammatory markers called CRP and IL 6, the researchers added, at rates up to 50 percent.

Inflammation was seen most often in individuals with high stress in their lives, including stress stemming from their socioeconomic status, childhood abuse or neglect, high fat diets or high body mass index.

The study’s co-author, Christopher Fagundes, said that previous studies indicated that patients with these predispositions have higher risk for mental illness because of the stressors in their lives — resulting in a higher incidence of chronic inflammation. Fagundes said this was linked to depression, but that it was normal to have an inflammatory response, like redness, for an injured area of the body.

“This is your immune system working to kill that pathogen, which is a good thing,” Fagundes said in a press release. “However, many individuals exhibit persistent systemic inflammation, which we’re finding is really the root of all physical and mental diseases. Stress, as well as poor diet and bad health behaviors, enhances inflammation.”

Comorbid inflammation and depression is resistant to therapy, the researchers also found. Activities such as yoga, meditation, NSAIDs and exercise helped the patients.

Fagundes, who hopes that this paper will shed light on the dangerous mix of inflammation and depression, is initiating a five-year, $3.7 million bereavement study to examine the effects of depression and grief on inflammation. He wants to find better ways to treat grieving older adults.

“We still have a lot to learn about how inflammation impacts depression, but we are making progress,” Fagundes added. “We hope one day this work will lead to new treatments that are part of standard psychiatric care.”