Could Inflammation Be Affecting Your Mood?

Have you ever wondered why your mood feels off—even when everything in your life seems fine? Or maybe you’ve been dealing with depression or anxiety and haven’t found lasting relief, despite trying multiple treatments. One possible reason could be inflammation. Yes, the same process your body uses to heal a cut or fight off an infection might also be quietly affecting how you feel emotionally.

What Is Inflammation?

Inflammation is your body’s natural response to injury, stress, or illness. It’s part of your immune system’s defense system and is usually a good thing—helping your body heal. But when inflammation sticks around longer than it should or happens in the wrong places (like your brain), it can create problems. One of those problems may be how your brain regulates mood.

How Is Inflammation Linked to Depression and Anxiety?

Research over the past two decades has uncovered strong links between inflammation and mood disorders like depression, anxiety, and bipolar disorder. In a significant number of people with these conditions, certain inflammatory markers—such as CRP, IL-6, and TNF-alpha—are found at higher levels in the blood (Miller, 2020; Felger, 2017; Rosenblat et al., 2014).

These markers can actively interfere with how your brain works. Inflammation may reduce important mood-regulating chemicals like serotonin and dopamine, increase a chemical called glutamate (which can be harmful in high amounts), and even interfere with the brain’s ability to grow and adapt (Haroon et al., 2017; Mechawar & Savitz, 2016).

What Happens Inside the Brain?

Even if your blood work looks normal, inflammation might still be happening inside your brain. Scientists have found evidence of brain-based inflammation—called neuroinflammation—in people with mood disorders. This includes the overactivation of immune cells in the brain (called microglia), changes in supportive brain cells like astrocytes, and inflammatory changes seen in brain tissue (Mechawar & Savitz, 2016; Giridharan et al., 2019).

Brain scans also reveal that inflammation can affect areas like the amygdala, prefrontal cortex, and basal ganglia—regions deeply involved in mood, motivation, and emotional regulation (Felger, 2017; Agarwal et al., 2022).

Can Inflammation Cause Depression?

Interestingly, when researchers give people substances that trigger inflammation—like interferon-alpha or bacterial toxins—it can cause temporary symptoms of depression, even in those who’ve never experienced it before (Miller, 2020; Rosenblat et al., 2014). This suggests that inflammation isn’t just a side effect of depression—it may help cause it in some people.

Is There a Way to Treat Inflammation-Related Depression?

There’s growing hope in the research: anti-inflammatory treatments—including medication, supplements, and lifestyle changes—have helped some people with mood disorders, especially those with high inflammation (Jones et al., 2020; Chang & Chen, 2020). This includes common anti-inflammatory strategies like omega-3 supplements, exercise, stress reduction, and dietary changes.

For example, research from clinical trials and systematic reviews shows that the Mediterranean diet helps lower levels of key inflammatory markers in the blood, such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). This supports its role in reducing chronic, low-grade inflammation linked to conditions like depression, heart disease, and diabetes.

But not everyone with depression or anxiety has inflammation. Research suggests that only about 25% to 50% of people with mood disorders show high levels of inflammatory markers (Miller, 2020; Jones et al., 2020). This means inflammation may be part of a specific subtype of depression, which could guide more personalized treatments in the future.

It’s a Two-Way Street

Your mental health affects your body too. Depression and chronic stress can increase inflammation, and that inflammation can then worsen your mood—creating a cycle that’s hard to break (Bauer & Teixeira, 2019; 2021). This feedback loop is one reason it’s so important to address both the emotional and physical sides of mood disorders.

Focus On the SMILES Trial: Anti-Inflammatory Diets Work to Treat Depression

One of the most exciting breakthroughs in this area came from a study called the SMILES Trial, published in 2017. This landmark randomized controlled trial asked a simple but powerful question: Can changing your diet actually improve depression?

The answer? Yes.

Main Findings

Participants with moderate to severe depression—many of whom were receiving antidepressant treatment without full symptom resolution—experienced significantly greater reductions in depressive symptoms when following a structured, anti-inflammatory diet, compared to those receiving social support alone.

What Was the Diet?

Participants met with a clinical dietitian for seven individual sessions over 12 weeks. They were guided to follow a modified Mediterranean-style diet, rich in:

• Vegetables, fruits, whole grains, legumes, and nuts
• Fish, lean meats, and olive oil
• Minimal processed foods and added sugar

The control group had the same number of sessions, but instead of dietary help, they received non-directive social support.

Why This Matters

• Better diet = better mood: Improvements in diet quality were closely linked with fewer depressive symptoms (Jacka et al., 2017).
• Works with other treatments: Most participants were already receiving medication and/or therapy, suggesting that diet is a powerful adjunct therapy that can be used in combination with medication or on its own.
  
• Real-world practical: A Mediterranean-style diet is not extreme. It’s flexible, delicious, and accessible for most people.

What This Means for You

If you’re struggling with depression and haven’t looked at your diet yet, this could be a powerful place to start. While food alone might not be a magic cure, it can play a key role in reducing inflammation and supporting your mental health alongside other treatments. 

What If Your Blood Tests Are Normal?

Here’s something important to remember: just because your blood work doesn’t show inflammation doesn’t mean it’s not there.

Inflammation can be localized, especially in the brain, and might not show up on routine tests like CRP or white blood cell count. Yet this hidden inflammation can still affect how you feel, think, and function (Mechawar & Savitz, 2016; Doney et al., 2021). So if you’re experiencing persistent mood symptoms that aren’t responding well to traditional approaches, it’s worth considering whether inflammation could be part of the picture.

Final Thoughts

Inflammation—whether in your body or your brain—can play a significant role in mood disorders like depression and anxiety. While not everyone with these conditions has inflammation, for many people it’s a key piece of the puzzle. And that means new hope: from anti-inflammatory treatments to dietary changes like those seen in the SMILES Trial, more personalized, root-cause approaches are becoming possible.

If you are feeling signs & symptoms of inflammation, whether your blood work is normal or not, consider lifestyle strategies that reduce inflammation—like improving your sleep, stress management, whole-food nutrition, gentle movement, and gut support. Check out my Inflammation Playlist where I place all videos related to inflammation including root causes, anti-inflammatory diet, supplements & more.