The connection between mind and body, or more specifically, between the brain and body, has been known for a long time.
Many scientists believe there is a direct link between mental state, especially stressful states such as anxiety, depression, or anger, and the body’s strength. Even the ancient Greeks proclaimed “healthy mind, healthy body,” but only recently have studies shown the direct link between neurotransmitters, acting mainly between the central and peripheral nervous system and the immune system.
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One of the researchers whose work led to this insight is Dr. Mia Levite from the School of Behavioral Sciences at the Tel Aviv-Yaffo Academic College. In a research she conducted with Prof. Yitzhak Koch from the Neurobiology department at Weitzman Institute and research students Alon Chen, Yonatan Ganor, Shai Rahimifar, and Nurit Ben-Aroy, and which was published in the scientific journal Nature Medicine, Dr. Levite managed to show that neurotransmitters can result in activation of certain cells (type T) in the immune system.
Dr. Levite asked herself if it is possible that substances produced in the brain are able to affect the immune system, whose function is to protect the body from external pests such as viruses or harmful bacteria. The surprising answer is yes. Moreover, there is a very strong relationship between neurotransmitters and the immune system, and this relationship is a two-way system.
Dr. Levite gathered her insights with that of other Israeli and foreign researchers in a recently published scientific book that she edited. Its name, Nerve-Driven Immunity, refers to the ability of nerves (nerve cells, neurons) to influence and encourage the immune system. In fact, a large portion of the neural transmitters mentioned in the book are fully or partly familiar.
Anyone who takes antidepressants in the SSRI family (Selective Serotonin Reuptake Inhibitor) – such as Prozac, Lexapro and their derivatives – is familiar with serotonin, considered a “happiness drug.” The same is true for another neurotransmitter, dopamine, which is responsible in part for good moods, energy and vitality.
Then there is also adrenaline, non-adrenaline, and neurotransmitters such as opioids (opiates like heroin and morphine that are known for their pain-relieving power) or cannabinoids (receptors for cannabis and its derivatives, marijuana, hashish, and charas).
Discovering how depression affects physical health
The new book describes new discoveries and recent research on the direct and powerful influence of neurotransmitters on the immune system. These discoveries could have critical scientific and medical impact, such as developing new treatments and medicines for immunological diseases (diseases of a lack or excess of immunotherapy) and neurological diseases (diseases associated with the central or peripheral nervous systems).
“The first revolution presented in the book is the way of looking at neurotransmitters,” says Dr. Levite. “Until today, these transmitters were unknown as materials that could have a direct influence on the immune system. In the book we show how they are directly linked to the immune system and have influence on the activation, amplification, suppression and weakening of many important activities done by immune system cells.”
The second revolution in the book has to do with the form of perceiving the identity and origin of materials that affect the immune system. According to new discoveries presented in the book, immune system cells can be activated or suppressed by neurotransmitters that are produced in the brain’s nervous system. “In other words, activation of the immune system by ‘brain messengers’ and the nervous system can also take place in the absence of external or internal threats to the body,” she explains.
The book argues that if this is true, we may finally be standing at the beginning of an era that will allow us to understand the direct way in which a healthy brain and mind strengthen the immune system and thereby contribute to the body’s durability against disease-causing factors, external or internal.
The book shows that we may indeed have found the way, that earlier we only felt existed and now we can almost see, in which negative events and experiences in our life – stress, depression, trauma, or brain injury – can cause direct and rapid disruption in the functioning of the immune system, thereby causing hypersensitivity and even the development of infectious and auto-immune diseases and cancer.
“Lexapro affects the immune system”
Dr. Levite explains the possible uses of these discoveries: “they have use in two main areas. The first is knowledge itself. To date, most doctors, including psychiatrists, do not know and so they do not tell their patients this information, all the while prescribing them different drugs, such as antidepressants that are tied to the enlargement of certain neurotransmitters. Lexapro, and all related drugs, is a prominent example.
“I think the first and most important use is the knowledge that apart from its anti-depressant activity, which is welcome in itself, the amount of neurotransmitters can affect – for better or for worse – the immune system of patients taking these drugs.
“Theoretically, a person who takes these drugs that are related to the enlargement or reduction of neurotransmitters may be more vulnerable to infectious diseases or even cancer, as we have discovered that neurotransmitters activate, amplify, or weaken the immune system. I hope this information will soon be included in these medicines’ labels.
“Another use that I can think of is a very positive one, such as removing lymphocytes from a patient’s body (the three types of white blood cells that make up the immune system), exposing them outside the body to the neurotransmitter dopamine, which is known to increase and enhance lymphocytes’ activity, and then return them –after being exposed to dopamine – to the patient’s body.
“This would improve their chances of moving faster and attacking tumor cells, viruses, and bacteria more efficiently. It is like a combat unit that must fight in enemy territory. The commander gives a pep talk (outside the patient’s body) and then sends them into battle (back into the patient’s body). The fighters are more tenacious and courageous, and therefore more effective in eradicating the enemy.”
According to her, the insights that emerge about the two-way relationship between neurotransmitters and the immune system bring with them hope of increasing the deterrence and offensive capabilities of our immune system, and also for the opposite problem: autoimmune diseases, in which the immune system works in excess and attacks the body itself.
“In this case it would be possible to use this new knowledge to slightly suppress the immune system and stop it from attacking the body. It is also relevant in the cases of implant rejection, in which acceptance is critical, and therefore it is necessary to suppress or calm the immune system” says Dr. Levite.