Mental Illness Affects Immunity – Nigeria

Keywords: Mental illness, immunity, immune system, B lymphocytes, T lymphocytes, macrophages, neurotransmitters, Nigeria.


Mental Illness Affects Immunity – Nigeria. What is mental illness? How does the immune system work? Is the immune system related to mental illness? What happens with a poor immunity in the mentally ill?

Epidemiologists have shown that there is a link between life stressors and the risk of infections and inflammatory diseases.

The whole system is very complex, but the evidences are there that the brain is connected with the immune system.

A poor mental health can compromise the immune system. And a compromised immune system can predispose to a mental health disorder. This gives a vicious cycle.

What is mental illness?

According to the World Health Organization, a mental disorder or illness is a disturbance in the individual’s cognition, emotional regulation, or behaviour. So it affects the way we think feel and act.

There is usually a problem in the way the person functions, at school, work, home, society, etc. A problem in cognition means that the person has a problem in thinking, judgment, planning, etc.

The mental illnesses include depressive disorders, anxiety disorders, bipolar disorders, schizophrenia, etc.

How does the immune system work?

The immune system structure:

Our immune system is made up of cells, tissues, organs, etc. They include the white blood cells, the thymus, spleen, tonsils, lymph nodes, lymph vessels and bone marrow.

The white blood cells of the immune system are made up of the B lymphocytes and the T lymphocytes. These produce antibodies and signal killer cells to the invaders. They also have the natural killer cells and the macrophages.

A killer cell is a white blood cell that kills viruses, bacteria, etc. Macrophages are white blood cells that destroy microorganisms. They are seen in tissues in the body and in the blood stream.

The T lymphocytes and the macrophages also produce proteins called Cytokines. These cytokines ensure that the immune system does its job.

White blood cells can be seen moving through the blood stream. They are made at the bone marrow.

These lymphatic systems are seen throughout the body. They manage the fluids in the body, react to bacteria, etc. And they are made up of lymph nodes, lymph vessels and white blood cells.

The spleen is an organ that filters the blood and removes microbes, destroy old blood cells.

And the bone marrow produces red blood cells, white blood cells and platelets.

Thymus filters the blood and produces white blood cells called the T lymphocytes.

Function of the immune system:

Immunity involves the body’s ability to prevent the invasion of bacteria, viruses, etc. It also gives us the adequate tolerance to allergies, etc.

The major role of the immune system is to fight harmful substances and protect your body. It makes use of the mentioned cells to bring these about.

The immune system also makes antibodies and uses them to fight germs.  Antibodies help the body to fight germs or toxins produced by the microbes or germs.

Most germs or microbes have on their body what is called antigens. These antigens sensitize the immune system to produce antibodies. The antibodies mark these antigens for destruction, thus destroying the germs.

The immune system also keeps the record of every germ or microbes it has ever destroyed. This will enable the immune system to recognize these germs when next they invade the body. So that next time it encounters the microbes, it can easily fight them.

Is the immunity related to mental illness?

Immune system or immunity and mental health relationship is a two way traffic.

How mental illness affects the immune system:

The brain and the immune system communicate through a complex mechanism. People that are stressed have increased hormones called cortisol. And cortisol can cause the decrease in immunity. It is known that chronic stress can reduce the number of killer cells or lymphocytes in the body.      

Depression also increases the level of cortisol. So depression affects the immune system making it hard for the body to fight infection.

The neurotransmitters have connections to the immune system.  Depressive disorders come about due to problems in the neurotransmitters of the brain, eg. serotonin. In depression, there is low level of serotonin. And serotonin is important in activating the immune system at the T and B lymphocytes. It also activates immunity at the macrophage level, aids the immune system in remembering microbes, etc.

So when serotonin is low such as in depressive disorders and in anxiety disorders the immune system gets compromised. Low serotonin is also involved in inflammatory processes.

There is also a link between schizophrenia and serious infections such as HIV, bacterial and viral.

Also there is an increased risk of getting infection with persons who abuse substances than those who don’t.

The effect of immune system on mental illness:

Some studies have it that infections may also be the cause of various psychiatric illnesses.

So chronic infections, can lead to psychological illness. There is the postulation that the genes for schizophrenia interact with certain infective agents, to cause the mental illness. Some of these infections, viral in nature, are said to occur when the person is still in the womb. Even infections in early childhood are predisposing factors.

Also some research have documented the relationship between maternal infections during pregnancy and the later development of autism in the child.

The brain has cells called microglia. These are macrophages in the brain. They perform local immune functions in disease states.

They are involved in pruning and are involved in excessive pruning that brings about schizophrenia in adolescents. Pruning is the destruction of old, unused, weak, or diseased brain cells.

Cytokines can disrupt the levels of neurotransmitters like serotonin, dopamine, glutamate, etc. that have their roles in depression. They can also predispose to anxiety, affect motivation and arousal.

What happens with a poor immunity in the mentally ill?

When the immunoty is weakened there is an increased risk of getting infected by viruses, bacteria, fungal, allergens, etc.

So the person can be at risk of having frequent colds, diarrhea, poor wound healing, and infections at any part of the body.

In Nigeria, there could be an increased risk of having serious forms of malaria, typhoid, HIV and AIDS, etc.

There is also the risk of cardiovascular diseases, arthritis, etc. Mental illness affects immunity in Nigeria, as it does globally.

This simply means that people with mental illness are more prone to having frequent infections and other physical illnesses. And if the mental illness is not treated there is a possibility of early or premature death.

Research has documented that infections are associated with high risk of premature death in people suffering from schizophrenia.

Other research papers have also shown increased risk of death in people suffering from depression due to infections. 


Intervention is multidisciplinary. This means there is need to consult psychiatrist and psychologist and an appropriate physician, depending on the associated physical illness.

The psychiatrist will take care of the mental health issues with medications. Some medications are also known to improve immunity.

 The psychologist will use psychotherapy methods like Cognitive behavioral Therapy (CBT) to also treat the mental health disorders. Psychotherapy is also relevant in improving immunity.

There is need to treat the infections or other complications when they occur by the appropriate physician.

Taking fruits rich in vitamin C and Zink are also known to improve immunity. Taking supplements of the vitamin and mineral can also help to improve immunity. But care must be taken not to take excess of Zink supplements which can be dangerous to health.

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