Depression – A symptom of an inflamed brain.

Posted on


There is a lot of buzz about inflammation in healthcare these days. Not the acute inflammation we get when we have an injury, but the low-grade, chronic inflammation that can cause harm, overtime, to our arteries, joints, kidneys, and even our brains.

I remember sitting in a conference hall, listening to Dr. Jeffery Bland PhD. introduce the subject of chronic, low-grade inflammation, about 11 or 12 years ago, before inflammation had hit the big time. He outlined in scholarly detail, with graphs and studies and tissue slides, how persistent low-grade inflammation was a common element of many conditions, and that he felt addressing it would require the skill and knowledge that naturopathic doctors have.

It interested me, and given my practice focus in mental and neurological health, I naturally started paying attention to research on inflammation and its effects on the brain. Most of what I learned at that time was about how inflammation plays a role in various neurological diseases. It is generally considered to play a key role in the development and progression of Alzheimer’s Dementia, Parkinson’s Disease, and ALS to name a few. In all these instances, however, inflammation was considered a pathological mechanism. At the time, no one was attributing a discrete symptom directly to inflammation itself.

In the world of mental health and neurology, depression is an interesting issue. It is a common co-morbidity to a whole host of problems. Here is a short list of mental health and neurological disorders that are associated with high risks for depression: Multiple Sclerosis, Obsessive Compulsive Disorder, Psychosis and Schizophrenia, PTSD, Traumatic Brain Injury, Parkinson’s Disease, ADD and ADHD, Stroke, Autistic Spectrum Disorder, and Panic disorder. Depression commonly co-occurs in many physical ailments such as cancer, heart attack (during recovery), arthritis, asthma, and diabetes.

If you compare depression to other mental health concerns like OCD or Panic disorder, it is truly remarkable how many conditions and situations are linked to depression. This is why researchers started wondering if we should think of depression differently. Instead of a simple mental health condition, discrete unto itself, it may be more accurate at times, and more useful, to view it as a symptom. The growing consensus is that depression one state that we may experience when our brains are inflamed.

This is a truly interesting consideration. We all know that if our joints and muscles are inflamed, we feel pain. With our brains, it may be that one way we experience neural inflammation is by feeling depressed. Depression has been known to be associated with increased inflammatory markers in the blood for some time now, but to say inflammation is a cause of depression as a symptom, is a bit different.

It may explain why depression so commonly co-occurs with other medical conditions as mentioned above. For instance, in Parkinson’s Disease (PD), we know there are very high levels of inflammation in the brain tissue, and the depression that is often experienced by people with PD may be a result of that.

The same phenomena might even explain disease processes in other mental health conditions. The severe depression that follows manic episodes in bipolar disorder may be due to the high levels of inflammation created in the brain during that event. The negative symptoms in schizophrenia that so closely mirror depression may also be caused by inflammation.

Of course for patients, this is all interesting, but only really important if it leads to improvements in treatment options for depression. Several antidepressants have now been found to exert anti-inflammatory effects in both the brain and the rest of the body (1, 2, 3). This might mean that beyond changing the way the brain uses serotonin and other neurotransmitters, these medications also exert anti-inflammatory effects on the immune system in a way that helps depression.

One blood marker for inflammation I will often check in folks with depression, and other neurological or mental health conditions, is CRP (C Reactive Protein).   CRP is an “acute phase reactant.” When we have an infection or injury, the liver releases very large amounts into the blood stream. It can also be elevated in people with chronic low-grade inflammation. People with elevated inflammatory markers seem to have a harder time responding to anti-depressants, but do better with particular ones or combinations of drugs (4).   As a naturopath, I consider folks with elevated CRP more likely to need other supports that naturopaths can offer to get inflammation down in order to adequately treat depression.

There are many ways to reduce inflammation throughout the whole body and the brain that are non-pharmaceutical. For instance, exercise, among its many benefits, reduces inflammatory mediators and is known to improve mood. Omega 3 fatty acids (fish oil) are already recognized as effective tools in treating depression in humans (6). Fish oil is also an excellent intervention for neuroinflammation. Mice given lipopolysaccharide, which tricks the immune system into thinking it has an infection, will develop depressive symptoms. Researchers could prevent depressive behaviours by giving the mice fish oil (5).

Dietary interventions such as reducing sugar and simple carbohydrate intake, and increasing vegetable intake reduce inflammation. Losing weight will directly reduce IL-6 production (4). Alcohol intake, if over 3-4 units per week, can have considerable pro-inflammatory effects, especially in women.

Taking stock of all the various ways we can control inflammation in our bodies truly outlines the benefit of the naturopathic system of health care in this instance. We think big with each person, and assess a broad range of factors contributing to our patients’ health. Beyond providing antidepressants if needed, naturopaths can improve gut health, encourage appropriate exercise, recommend dietary change and supplementation. And a growing body of evidence supports more and more of what we do.

I am personally very passionate about helping folks experiencing depression. Regardless of the cause, there are few greater delights in my day than seeing a patient who is recovering from depression.  Assessing for inflammation is one of many evidence-based tools I use to guide a treatment plan for someone with depression. After 17 years of practice focused in mental and neurological health, I believe that assessing for inflammation in patients with depression to be important, and likely to enter main-stream medicine in the near future.

Dr. Pamela Hutchison is the CEO of Acacia Health and a Naturopathic Physician with a clinical focus on mental and neurological health care. She has over 17 years of experience and remains a passionate learner who continually reviews current research in mental health and neurology



1: Gałecki P, Mossakowska-Wójcik J, Talarowska M. The anti-inflammatory mechanism of antidepressants – SSRIs, SNRIs. Prog Neuropsychopharmacol Biol Psychiatry. 2018 Jan 3;80(Pt C):291-294. doi: 10.1016/j.pnpbp.2017.03.016.

2: Sandra Sacre, Mino Medghalchi, Bernard Gregory, Fionula Brennan, and Richard Williams. Fluoxetine and Citalopram Exhibit Potent Antiinflammatory Activity in Human and Murine Models of Rheumatoid Arthritis and Inhibit Toll-like Receptors. Arthritis & Rheumatism, Published Online: February 25, 2010 DOI: 10.1002/art.23704

3: Tynan RJ, Weidenhofer J, Hinwood M, Cairns MJ, Day TA, Walker FR. A comparative examination of the anti-inflammatory effects of SSRI and SNRI antidepressants on LPS stimulated microglia. Brain Behav Immun. 2012 Mar;26(3):469-79. doi: 10.1016/j.bbi.2011.12.011.

4: Jha MK, Trivedi MH. Personalized Antidepressant Selection and Pathway to Novel Treatments: Clinical Utility of Targeting Inflammation. International Journal of Molecular Sciences. 2018;19(1):233. doi:10.3390/ijms19010233.

5. Shi Z, Ren H, Huang Z, Peng Y, He B, Yao X, Yuan TF, Su H. Fish Oil Prevents Lipopolysaccharide-Induced Depressive-Like Behavior by Inhibiting Neuroinflammation. Mol Neurobiol. 2017 Nov;54(9):7327-7334. doi: 10.1007/s12035-016-0212-9.

6. Burhani MD, Rasenick MM. Fish oil and depression: The skinny on fats. J Integr Neurosci. 2017;16(s1):S115-S124. doi: 10.3233/JIN-170072.