The hidden link between depression and the immune system— And what Covid-19 taught us

When we think of depression,  we usually imagine feeling sad, tired, or hopeless. And when we think of the immune system, we think of fighting off colds and viruses. But what if I told you that these two are closely connected?

Thanks to the COVID-19 pandemic, scientists got a much closer look at how our minds and bodies affect each other, especially when it comes to mental health and getting sick.

Can Depression Make You Physically Sick?

Yes, it can. Depression doesn’t just affect your thoughts and emotions, it also changes how your body works.

When you’re depressed, your body can:

•Produce more inflammation, like it does when you have a fever.

•Weaken your immune system, making it harder to fight off viruses like the flu or COVID-19.

🔬 One study in JAMA Psychiatry found that people with depression often have more inflammation in their bodies. This can mess with your immune system.

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Example from COVID:

During the pandemic, researchers noticed that people with depression or anxiety had a higher risk of getting seriously sick from COVID-19. Their immune systems weren’t responding as well, possibly because of the stress their body was already under.

Can Getting Sick Affect Your Mental Health?

Absolutely. When your body fights off an infection (like COVID-19), your immune system sends out chemicals to help. But these same chemicals can change how your brain works.

This can make you:

•Feel sad, tired, or unmotivated

•Have trouble focusing

•Lose interest in things you usually enjoy

This is something doctors call “sickness behavior,” and it can look a lot like depression.

🧪 A 2021 study in The Lancet Psychiatry showed that almost 1 in 3 people who had COVID-19 developed some type of mental health issue within 6 months—often depression or anxiety.

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Pandemic Stress Made Things Worse

Even if you didn’t catch COVID-19, just living through the pandemic was stressful. Think about it:

•Being stuck at home

•Losing jobs or loved ones

•Worrying about the future

All this stress can raise levels of cortisol (a stress hormone), which in high amounts can hurt your immune system too.

🌍 According to the World Health Organization, depression and anxiety increased by 25% worldwide during the pandemic.

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It Becomes a Vicious Cycle

Here’s what often happens:

1. You feel depressed →

2. Your immune system gets weaker →

3. You get sick more easily →

4. Being sick makes you feel more depressed →

5. And the cycle continues…

   
   

That’s why it’s so important to take care of both your mental and physical health. They’re not separate, they work together.

Depression isn’t just “in your head”, it can affect your whole body. And when your body is under stress, it can affect your mental health too.

The COVID-19 pandemic helped scientists better understand this connection. Now, more than ever, it’s clear: Taking care of your mind helps your body, and taking care of your body helps your mind.

Your brain and your body are always talking to each other. When you take care of one, the other listens, so give both the attention they deserve.