Mental health issues have a huge impact on society. Some suggest that their impact is larger than any other chronic disease, including heart disease or diabetes. There are so many factors involved in complex conditions like mental health issues. Science is just starting to unravel one of these factors - inflammation. 

What is Inflammation?

The word inflammation comes from the Latin word “inflammo,” meaning “I set alight, I ignite.”

Because inflammation can become harmful, it has gotten a lot of bad press lately. However, inflammation isn’t always a bad thing. As in most areas of health, it’s the balance that’s important.

Inflammation is actually a natural process that our body uses to protect against infections, irritants, and damage. Inflammation helps our bodies eliminate damaged cells and tissues, and helps them to repair. It also helps to reduce the cause of the damage, for example, by fighting the infection. Inflammation that happens in a big way, but for a short time can help the body to heal these injuries and infections.

On the other hand, lower levels of inflammation sometimes stick around longer than necessary. This long-term “chronic” inflammation can cause damage over time. Often, there are few, if any, signs or symptoms. It’s this chronic inflammation that is linked to many conditions including mental health, heart disease, and diabetes.

Inflammation mostly comes from our immune system’s response to infections and injuries. It also involves our blood vessels (arteries and veins) and other molecules. A few of these inflammatory molecules, or “markers,” include free radicals (oxidants), cytokines, and C-reactive protein (CRP).

So, what are the links between inflammation and mental health?

Inflammation and mental health

There are many factors linked to suboptimal mental health. One of these is inflammation.

In terms of depression, the link with inflammation was first discovered back in 1991. With respect to bipolar disorder, the link between it and immune dysfunction was proposed as far back as 1981.

NOTE: While there are many links between inflammation and mental health issues, it’s not the only connection. Others include neurotransmitter issues (e.g. serotonin, dopamine, etc.); reduction in growth factors (e.g. brain-derived neurotrophic factor, BDNF); and neuroendocrine issues (i.e. chronically increased stress hormone levels).

Research shows that inflammation may be a factor for about one-third of people with depression.

This article focuses specifically on the links between inflammation and mental health.

Link 1 - Inflammation and mental health

First of all, some mental health issues are associated with increased inflammatory markers like cytokines and CRP. For example, people with depression tend to have higher levels of cytokines. In fact, some of the inflammatory markers found in the blood are known to reach the brain.

High levels of inflammation may also inhibit recovery in people who experience mental health symptoms.

In fact, some researchers believe that levels of inflammation may actually be able to predict negative mental health outcomes.

While inflammation may be part of the cause of mental health symptoms for some people, it can go in both directions. Mental health issues may also increase some of these inflammatory markers.

Some animal studies show that stress can cause significant increase in inflammatory markers. Even people who are stressed tend to have increased levels of inflammatory markers and lower levels of anti-inflammatory markers.

Link 2 - Inflammatory illnesses and mental health

Inflammatory illnesses like allergic and autoimmune diseases, as well as metabolic conditions (e.g. heart disease, diabetes, and obesity) are associated with higher rates of mental health symptoms.

And this link also goes both ways - people with mental health symptoms are more likely to get metabolic-related conditions.

This link between mental health symptoms and metabolic conditions has led some researchers to coin the term “mood-metabolic syndrome.” This is meant to reflect the fact that they’re linked to each other, and also that these links can go both ways.

Link 3 - Inflammatory medications and mental health

People who take certain inflammatory medications are at increased risk of developing mental health symptoms. On the other hand, some medications used to treat depression (e.g. SSRIs) reduce levels of some inflammatory markers.

Link 4 - Inflammatory diets and mental health

There is growing evidence that people who eat a high quality diet tend to have a better sense of well-being and better mental health. This includes better moods and lower stress. Certain anti-inflammatory diets have lower rates of mental health issues.

This also means that studies show links between unhealthy eating patterns and mental health issues. Inflammatory diets are associated with higher rates of mental health symptoms.