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Depression and Immune System

Depression and Immune System: The Surprising Connection

Writen By: Sadia Mirza
Reviewed By: Huma Khan
Publish Date: May 21, 2024

Have you ever considered the intriguing connection between depression and immune system? It’s interesting to think about how mental health affects our body’s ability to fight off illnesses and infections. Given that depression is the most common mental health problem and impacts individuals in various ways, it is likely that it also affects our immune system.

The relationship between our mental and physical health is closely interconnected. Research suggests that there is a significant correlation between the two, with each affecting the other. For instance, when we experience depression and anxiety, it can also impact our immune system.

This blog post will explore the correlation between depression and immune system. We’ll examine how does depression affects the immune system and provide actionable steps to help boost both mental health and immunity. Join us as we delve deeper into the concepts of depression and immune system and don’t forget to check out our recommended self help books at the end for further guidance on improving both mental and physical health.

What is Depression?

Depression is a mental illness that has an adverse effect on one’s feelings, thoughts, and behavior. It can disrupt everyday activities and result in a variety of mental and physical issues, including protracted depressive symptoms. 

Depression and immune system


According to a research study, approximately 21 million adults in the US suffer from depression. Research also shows that women are more likely than men to experience depression due to the numerous hormonal changes that women experience during pregnancy, menopause, and the postpartum period.

Symptoms Of Depression

According to DSM-5, depression can be diagnosed by the presence of five or more of these symptoms for at least two weeks, which cause significant distress:

  • There is a lingering sense of emptiness or sadness. For at least two weeks, this feeling may linger for most of the day, almost every day.
  • A noticeable decline in interest in or enjoyment of previously enjoyed activities is also present. This can include hobbies, work, or social activities.
  • Loss of energy or increased fatigue can make it difficult to get things done at work, school, or home.
  • There is difficulty thinking, concentrating, making decisions, or remembering things, and this can make it difficult to focus at work or school.
  • Restlessness or feeling slowed down.
  • Feelings of worthlessness or guilt, which include negative self-talk and feeling like a burden to others.

What is the Immune System?

The immune system is our body’s defense system. It is a complex network of cells, organs, tissues, and proteins that work to protect our body from harmful bacteria, viruses, and parasites. The immune system helps our body heal from injuries and fight off diseases. 

Depression and immune system

Role Of the Immune System in Our Body

The immune system acts as our first line of defense against invaders that could cause harm and works together tirelessly to safeguard our health.

Let’s read in detail about the immune system’s crucial role in our body:

1. Fighting infection: The immune system kicks into action when a germ enters your body. It identifies and isolates the threat, then establishes a multi-pronged attack to destroy it. This can involve:

  • White blood cells: White blood cells are specialized cells, like lymphocytes and phagocytes, that directly target and eliminate pathogens.
  • Antibodies: Antibodies are proteins, produced by lymphocytes, that bind to specific pathogens, rendering them harmless and marking them for destruction by other immune cells.
  • Inflammation: This localized response involves increased blood flow and immune cell activity to isolate and fight the infection.

2. Maintaining self-tolerance: 

Our immune system is finely tuned to distinguish between “self” ( the body’s own healthy cells) and “non-self” (foreign invaders). This prevents the immune system from attacking our own tissues that exist in our body, which can also possibly lead to autoimmune diseases.

3. Surveillance and repair: The immune system constantly monitors our body for any signs and warnings of trouble, including abnormal cell growth that could indicate cancer. It also plays a great role in healing wounds and repairing damaged tissues.

4. Remembering past threats: When the immune system encounters a new pathogen, it “remembers” it, as it got saved in it like a memory. This allows for a faster and more effective response if the same pathogen attacks again, which is the principle behind vaccination.

Knowing the definitions of depression and immune system, let us investigate the relationship between the two and determine whether or not depression has an impact on immune cells.

The Connection Between Depression and Immune System

The immune system is like our body’s army, which is constantly on guard against threats. But this army can be affected by many factors and one of them is depression. So let’s study the relationship between depression and immune system in the light of research studies.

Our mind and body are connected and interviewed so if we go through any mental health problems, it affects our physical health too. When we are depressed, it has physical effects on our body. So the question here arises: does depression lower your immune system? Research shows that depression and stress have a great impact on the human body, especially on the immune system, causing infections, diseases, and even cancer. 

According to a study published in Translational Psychiatry (2022), people with depression had immune cells in their blood that were more deformable compared to healthy individuals. Normally, healthy immune cells can change shape to squeeze through narrow blood vessels to reach infection sites. The researchers suggest that these more deformable cells might be less efficient at fighting off infections. This could contribute to why people with depression are more likely to get sick. Overall, this study adds another piece to the puzzle of the depression-immune system connection.

The relationship between depression and immune system is complex and the direction of their influence can go both ways, with depression affecting the immune system and the immune system causing depression. 

How does depression affect the immune system?

  • Depression is often accompanied by stress, which can repress the immune system’s response. Stress hormones like cortisol can inhibit the production and function of immune cells, which makes an individual more susceptible and prone to infections and it also takes longer to recover from illnesses.
  • White blood cells (part of the immune system) are essential for fighting off infections. Chronic stress associated with depression can deform the structure and reduce the production of white blood cells, leaving your body more vulnerable to illnesses.
  • Depression can interfere with the balance of immune system chemicals called cytokines, which help regulate immune responses. As a result of this imbalance, your body may find it hard to develop a strong defense against pathogens. 
  • Research shows that depression and fatigue have been associated with increased inflammatory activation of the immune system. This can weaken the immune system’s ability to fight off pathogens and lead to various health problems.
  • Depression can disturb sleep and lifestyle patterns and habits such as regular exercise and a balanced diet, all of which are crucial for healthy immune function. 
  • Studies have shown that people with depression may have a diminished response to vaccines, meaning they may not develop the same level of immunity as those without depression.
  • Research shows that stress hormones like glucocorticoids initiate changes in the hypothalamic pituitary adrenal axis and the immune system, worsening anxiety and depression. 

How does the immune system impact depression?

  • Chronic inflammation in the body, even at low levels, has been linked to depression. The immune system’s inflammatory response triggers the release of chemicals that can disrupt brain function and contribute to depression.
  • A research study was conducted to show how social stress, like repeated social rejection, might trigger changes in the brain’s immune system.  The study suggested that social defeat stress activates specific immune system receptors (TLR2/4) in brain cells called microglia. These microglia reside in the prefrontal cortex, an area crucial for decision-making and social behavior.  The activation of these microglia might be involved in causing social avoidance behavior which is a common symptom of depression.
  • Moreover, people with certain autoimmune diseases, where the immune system attacks healthy tissues, are more likely to experience depression. This indicates a potential link between the immune system and depression. According to a research, disruptions in the immune system, either through attacking healthy tissue (autoimmune diseases) or fighting off a major infection, might increase the risk of mood disorders such as depression.
  • Another factor is the gut microbiome which plays a role in mental health by influencing the production of neurotransmitters like serotonin, which affects mood regulation. A compromised immune system could disrupt the gut microbiome, potentially contributing to depression.

Hence, all these factors suggest a two-way street, where depression can weaken the immune system and vice versa. But its important to note that the exact nature of the connection between depression and immune system is still being researched. More scientific information is needed to fully understand the complex interplay between these variables.

Tips For Keeping Immune System Healthy

Now that you know that there is some connection between depression and immune system, so let’s take a look at how you can strengthen your immune system to stay healthy, avoid infections, and reduce the risks of mental health problems. 

Depression and immune system
  • Eating a healthy, balanced diet can be beneficial for the immune system. A diet rich in fruits, vegetables, and whole grains provides your body with the essential nutrients it needs to support immune function.
  • Getting enough and proper sleep helps to keep your immune system healthy. Most adults need 7-9 hours of quality sleep each night. Adequate sleep allows your body to repair and recharge, which strengthens your immune system.
  • There is a connection between chronic stress, depression, and the immune system, as stress and depression can weaken your immune system, so finding healthy ways to manage both of them is important. You can practice relaxation techniques like yoga, meditation, or deep breathing to manage stress effectively.
  • Exercise has so many benefits. Regular physical activity can help boost your immune system and overall health. Moderate-intensity exercise for at least 150 minutes per week can strengthen your immune system. Aim for activities you enjoy, like brisk walking, swimming, or dancing.
  • Laughter might be more than just good medicine, it could be a health booster too. A study suggests that a good laugh can improve immune function. It appears that laughter might be beneficial to your health but we are unsure if this will ultimately result in a lower rate of illness in the long run.
  • Water is important for overall health, including immune function. Aim to drink plenty of water throughout the day, at least 8 glasses each day.
  • Nicotine and alcohol can weaken your immunity so try to avoid smoking and drinking but if you can’t, at least do so in moderation.
  • Consider supplements like Vitamin D and C are well-known for their immune-supporting properties. But it’s important to talk to your doctor before starting any supplements, as they may not be necessary for everyone and can interact with medications.

Remember, a healthy lifestyle is essential for maintaining a strong immune system and protecting yourself from illness.

Treatment Of Depression

Depression is treatable and there are several evidence-based treatment options available for depression. It’s better to treat depression as well, so we can avoid its negative effects on our immune system. 

Depression and immune system

1. Psychotherapy (talk therapy)

This type of therapy involves talking with a mental health professional about your thoughts, feelings, and behaviors. It can give you a new perspective on problems. There are different types of Psychotherapies and the most effective type is Cognitive Behavioral Therapy.

2. Medications

Antidepressant medications can help to improve the balance of chemicals in your brain that are associated with mood. There are different types of antidepressants, such as sertraline, fluoxetine, and citalopram. You should consult with a doctor to find one that works best for you.

If you are going through depression or any other mental health problem, then it’s better to get treatment for it and consult a healthcare professional who can guide you better about your condition.

Top Books for Mental and Physical Health

  1. Cytokines and Depression: How Your Immune System Causes Depression: This book helps you understand the biological connection between your immune system and mental health. It provides information on how controlling inflammation may lessen symptoms of depression, giving readers the tools they need to enhance their general well-being.
  1. The Immune System and Mental Health: This book offers insights into how immune responses can influence mood disorders like depression. It provides practical strategies and evidence-based information for managing and improving both mental and immune health.
  1. The Inflamed Mind: A Radical New Approach to Depression: This book explains how inflammation in the body can contribute to depression, offering readers a fresh perspective on the biological links between physical and mental health, and providing insights into potential new treatments.
  1. Bulletproof Your Immune System: Overcome Disease, Virus & Depression: It helps readers by offering practical strategies to strengthen their immune system and manage depression through holistic approaches, enhancing both physical and mental well-being. The book provides actionable advice on diet, exercise, and lifestyle changes to build resilience against illness and improve mood.


In this blog post, we’ve explored how depression and immune system are closely linked. When someone is depressed, their immune system can weaken, making them more susceptible to illnesses and infections. Conversely, having a weak immune system or dealing with infections and autoimmune diseases can lead to depression. This shows a two-way relationship between mental health and immune health.

Our mind and body are deeply connected. When we are mentally healthy, we often feel physically well too. Therefore, taking care of our mental health is crucial for maintaining our physical health. Many physical illnesses can stem from mental health issues.

If you are experiencing depression, remember that there are various treatment options available. It’s important not to ignore depression, as it impacts both your mind and body. Ensuring both mental and physical health is essential for overall well-being.


1. What is the relationship between autoimmune disease and depression?

Autoimmune diseases and depression are closely related. An autoimmune disease is a condition in which your body is attacked by your immune system, leading to inflammation and other health problems. This ongoing stress on the body can lead to or worsen depression. Research suggests that this disarray within the immune system might also affect brain chemicals linked to mood, making you feel down or depressed. On the other hand, being depressed can also affect your immune system, making you more susceptible to autoimmune diseases. It’s a two-way street: the physical stress from an autoimmune disease can cause mental health issues, and mental health issues can negatively impact your immune system.

2. Why does depression weaken your immune system?

Depression affects the production of cytokines, which are proteins that regulate the immune system. This dysfunction can lead to a weakened immune response, making the body less able to fight off infections and diseases. Depression also causes changes in sleep, appetite, and other behaviors, which can further negatively impact the immune system.

3. Can antidepressants improve the immune system?

Antidepressants primarily help balance chemicals in the brain responsible for mood regulation, but they can also have positive effects on the immune system. By reducing stress and depression, antidepressants can lower inflammation in the body, which can strengthen the immune system over time. Some research suggests that antidepressants might directly influence immune cells, however, more research is needed to understand this fully. Overall, by improving your mental health, antidepressants can indirectly benefit your immune health.

4. Can a person become immune to antidepressants?

A person cannot become “immune” to antidepressants, but sometimes these medications lose their effectiveness over time. This phenomenon is called tachyphylaxis or “Prozac poop-out.” This makes a person feel that their depressive symptoms are returning, getting worse, or not improving as much. If this occurs, a doctor may adjust the dosage, switch medications, or add another type of treatment to help manage the symptoms.

5. Does serotonin affect the immune system?

Yes, serotonin, a key neurotransmitter that helps regulate mood, also plays a role in the immune system, according to research. Serotonin can influence the behavior of immune cells and reduce inflammation. It helps maintain the balance between the immune system and the brain, ensuring both work effectively. Low levels of serotonin are linked to both depression and weakened immune function, highlighting the connection between mental health and immune health.

6. How does mental health affect your immune system?

Mental health has a significant impact on your immune system. When you are stressed, anxious, or depressed, your body produces stress hormones like cortisol, which can suppress immune function. Chronic stress and poor mental health can lead to ongoing inflammation and reduce your body’s ability to fight off infections and diseases. Conversely, good mental health boosts the immune system, helping it to function optimally. Therefore, taking care of your mental health is essential for maintaining a strong and responsive immune system.