One traditional hypothesis of depression is that people who are depressed have a deficiency in monoamine neurotransmitters in the body, which leads to low levels of neurotransmitters like serotonin and norephinephrine in the brain. But growing evidence supports that at least some forms of depression may also be linked to ongoing low-grade inflammation in the body.
Previous studies have linked depression with higher level of inflammatory markers compared to people who are not depressed. When people are given proinflammatory cytokines, people experience more symptoms of depression and anxiety. Chronically higher levels of inflammation due to medical illnesses are also associated with higher rates of depression. Even brain imaging of people with depression show that their brain scans have increased neuroinflammation. When your body is in an inflammatory state fighting off the common cold or flu, you can experience symptoms overlapping with depression— disrupted sleep, depressed mood, fatigue, foggy-headedness, and impaired concentration.
A new study published in The Journal of Clinical Psychiatry supports the premise that increased inflammation may play a role in depression. The large study examined data from 14,275 people who were interviewed between 2007 and 2012 using the Patient Health Questionnaire (PHQ-9) to screen for depression and had blood samples drawn. They found that people who had depression had 46% higher levels of C-reactive protein (CRP), a marker of inflammatory disease, in their blood samples. The study was only able to establish an association between depression and inflammation but not causation, though it confirms the association of depression with high levels of inflammation as measured through CRP.
The theory that depression may be viewed as a psychoneuroimmunological disorder can also help explain why efforts to reduce chronic inflammation in the body also improves and helps prevent depression. Here are five scientifically proven ways you can help reduce inflammation:
Copyright © 2017 Marlynn Wei, MD
Soledad Cepeda, M., Stang, P., & Makadia R. (2016) Depression Is Associated With High Levels of C-Reactive Protein and Low Levels of Fractional Exhaled Nitric Oxide: Results From the 2007-2012 National Health and Nutrition Examination Surveys. J Clin Psychiatry. 1666-71.
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