Psychoneuroimmunology is the branch of biomedical science that explores the relationships between the nervous system, emotions, and the immune system; it is concerned with elucidating the links between our states of mind and our states of health. It is one piece of a very complex puzzle - the puzzle of what creates and maintains harmony and well-being.

Our physical bodies, like the physical structures of all living things, have evolved many systems that help to insure our survival. Survival is, in fact, a biological imperative and at the level of physical structure and function the body operates automatically to achieve the goal of keeping us alive. We all know that in order to live we must breathe, eat, drink, and maintain body temperature within certain limits. We also know that there is an element of “ranking” in these needs; we will die more quickly from lack of air to breathe than we will from lack of food to eat. What many of us are unaware of at a conscious level, however, is how necessary our immune systems are to even short term survival. If somehow we completely lost all immune function suddenly, we would die within minutes from the ravages of invading bacteria, viruses and other pathogens. The immune system's constant vigilance and response is an absolute necessity for even short-term survival.

Although the immune system has wide-reaching effects on the body's state of health, until comparatively recent times, immunologists believed that it was an autonomous system that functioned independently of other body systems . This belief arose, in part, from the observation that immune cells will kill viruses and bacteria in vitro; because these cells were seen to perform their function independent OF the body, the system was believed to operate independently WITHIN the body.

According to Steven Locke and Douglas Colligan, authors of the Healer Within, one of the reasons behind our slowness in elucidating the mechanisms and connections of the immune system is its diffuse representation and function:

The immune system defies simple anatomical description. The respiratory, circulatory, and nervous systems, as complex as they are, can be described as having a center and divisions. The center of the respiratory system is the lungs; of the circulatory system, the heart; of the nervous system, the brain. Although some regions of the body have important immune functions, the immune system has no identifiable center. It is as one expert characterizes it with some frustration 'a roving bag of cells without a fixed anatomy' (Locke. Steven & Cooligan, Douglas, The Healer Within, E.P. Duttonf, New York, 1986, pp 34 - 35 ).

While we can identify specific organs which are components of the immune system (most notably the thymus, spleen , adenoids, bone marrow, etc.), the immune system is “fluid”, both metaphorically and literally. In the literal sense, much of the immune system's activity is conducted through the body's two circulatory systems, the blood and the lymph. Lymph and blood carry fluids to every cell of the body and so the immune system is able to monitor and effect activities everywhere. Metaphorically, the immune system is fluid in its adaptation and response to changing conditions and this allows it to deal with threats in a timely and appropriate way.

Threats to the healthy functioning of the body come from two main sources: inside the body and outside of it. Threats from the outside include viruses, bacteria, fungi and other pathogens. Threats from the inside arise from abnormal cells produced by the body itself, such as cancer cells. When the immune system is functioning properly, foreign invaders and abnormal cells (referred to collectively as “antigens”) are detected promptly and destroyed and the normal functioning of the body is undisturbed. When the immune system is not functioning properly, due to either over activity of the system or under activity of the system, illness results. The following chart, adapted from The Healer Within, helps to illustrate the variety of results that arise from immune system dysfunction:


                                Overactive      Under active


   Outside antigen       allergy      infection


   Inside antigen      autoimmunity      cancer


Allergies, infections, autoimmune diseases, and cancer are illnesses that all arise from immune system dysfunction and all of us will suffer from at least some of these manifestations at some time. When you “catch a cold”, it is a sign that your immune system was not able to fight off an invading virus; perhaps the virus was too “strong” or your immune system was weakened. The fact that you eventually get over your cold is a sign that your immune system rallied to the challenge and fought off the invader.

While virtually everyone catches occasional colds or has had an infection of some kind or other, people vary tremendously in how frequently they experience these kinds of problems and many, many people never experience the more serious consequences of immune dysfunction, such as cancer and autoimmune diseases. Since all people are faced with more or less the same antigens, why do some people stay healthy and some do not. Why do some people's immune systems seem to hum along doing their job well, neither over-reacting nor under-reacting, while other people succumb to allergies, infections, cancer, and auto-immune disease? Of course this is a complicated question and the causes of illness are many and multi-factored. Genetics certainly play a part and even luck is a factor (if you're lucky you won't be exposed to Ebola virus, for example), but a very significant contributor to immune system function, and therefore to health, is your state of mind.

The recognition of the mind/body connection and the discovery of its routes and mechanisms of operation, through the emerging field of psychoneuroimmunology, represents one of the most significant and promising medical/scientific advances of the last two decades. Since the time of Descartes, Western medicine, like Western science and philosophy, has been ruled by the doctrine of dualism, which sees the mind and the body as separate. Dualism has in fact had a powerful and pervasive effect on the evolution of Western culture and its influence is felt whenever and wherever we experience ourselves as “separate” from other beings, from Spirit, and from the Earth. It is precisely this dualism and separation that holistic therapies seek to overcome and in a very real way, advances in psychoneuroimmunology are paving the way for the introduction of holistic practices into mainstream medicine.

So what exactly is this mind/body connection that is proving so important in the on-going evolution of medicine? How does it work? The basic premise of mind/body medicine is that our thoughts, feelings, and mental states influence our bodies at the physical level and express themselves in our health. The brain has often been called the organ of the mind. It is, at least at the physical level, both the source and executor of all that we think and feel and it is through the brain's connections with our other organs, glands, and tissues that feelings influence health.

The brain influences the body, including the immune system, through nerve fibers that reach into all of the organs, the endocrine system, the bones, the muscles, the lymph nodes, and every part of the body. It also exerts both direct and indirect effects through its own chemical messengers and those dispatched by the endocrine glands. The limbic system, which is an evolutionarily ancient collection of deep brain nuclei involved in the generation of emotional responses, reaches into the autonomic nervous system and the immune system through its connections with the hypothalamus.

The hypothalamus is a small subcortical mass of tissue about the size of your thump tip. Despite its small size, it is responsible for coordinating a great deal of the body's physiological activity. It has strong nerve connections with the brain stem reticular activating system (responsible for arousal and alertness); the amygdala and other components of the limbic system; the hippocampus (involved in memory); and, the autonomic nuclei of the brainstem and spinal cord. The hypothalamus also has connections with the retina and olfactory systems and these connections carry information utilized for control of circadian functions. The hypothalamus exerts control over many physiological functions such as temperature regulation, water balance, and blood sugar levels. It also produces hormones which lead to the release of other body chemicals which effect the immune system, including epinephrine, nor epinephrine, and corticosteroids.

The connections between the hypothalamus and the immune system are bi-directional: the brain not only transmits information to the immune system, but also receives information back from it. This is the basis of neuromodulation of immune function and it is the way in which states of mind influence the body and the way in which states of the body influence the mind.

The “Stress Response”, described by Hans Selye in the early 1970's, still offers one of the best illustrations of the mind/body connection. The Stress Response, which is also called the “Fight or Flight Reaction”, results in a series of events that occur in the body when a person experiences something that they perceive to be threatening or challenging. The evolutionary purpose of this response is to prepare the body to either fight or run away. Here's what happens:

When the hypothalamus gets the message from cortical centers that there is a threat, it acts on the adrenal glands through the sympathetic nerves and indirectly through the pituitary gland via the blood stream, causing the adrenals to release corticosteroids, epinephrine, and norepinephrine. Corticosteroids perform a variety of functions; they have anti-inflammatory effects, raise blood sugar, inhibit allergic reactions, mobilize fat and prepare the body for action in other ways. Epinephrine and norepinephrine also prepare the body by acting on the heart, blood vessels, and back again on the brain. As a result of sympathetic nervous system activation (release of epinephrine and norepinephrine) a number of body events occur, including:


- increased blood pressure

- increased respiratory rate

- increased heart rate

- increased fuel consumption

- increased blood flow to skeletal muscles

- increased muscle tone

- increased perspiration


A number of things have been found to happen in the immune system when the Stress Response is activated. Selye himself found that rats subjected to stress-producing conditions showed atrophied thymus glands on autopsy. However, since the role of the thymus in the growth of T-cells (specialized immune cells) was not known at the time, it was not until later that investigators began to understand the effects of stress on immune function. Many subsequent studies have demonstrated these effects. Joan Borysenko and a team of researchers at Beth Israel and Harvard discovered in the early 1980's that while elevated epinephrine levels were initially accompanied by increased lymphocytes in mildly stressed test subjects, within thirty minutes lymphocytes had decreased, signaling a decrease in immune system effectiveness. Further investigation also showed an increase in suppressor T-cells, a further indication that epinephrine impairs immune function.

Studies of stress in medical students have shown a negative impact of test anxiety on immune function associated with decreases in natural killer cells, T and B lymphocytes, and helper T cells (Kiecolt-Glaser, et. al. “Psychosocial modifiers of immunocompetence in medical students”. Psychosomatic Medicine, 1984, 46:7-14; Glaser, R. et. al. Stress depresses interferon production...Behavioral Neuroscience, 1986, 100(5): 675-78; Glaser, R. et. al. “stress related impairments in cellular immunity". Psychiatry Research, 1985, 16:233-39).

Studies examining long-term stress have also shown immune system effect. For example, Ader et. al report a drop in activity of natural killer cells and a decrease in the proportion of helper T-cells, accompanied by subjective reports of a higher incidence of symptoms of illness in medical students under stress (Ader, Cohen & Felton. “Psychoneuroimmunology: interactions between the nervous system and the immune system”. Lancet, Jan 14, 1995; 345(8942); 99-103).

The Stress Response and its accompanying effect on the body is designed to help the organism survive a physical threat. Previously, it was noted that survival is a biological imperative. The body will do what it must to survive an immediate threat. In the case of attack, the body will mobilize its resources to help you fight or run away, even though this apparently means that at least some aspects of immune function will drop. This way of responding has been with us throughout our evolutionary development from earlier stages. It was certainly with us for the uncountable era before we became “modern” humans. In those long past earlier stages of our existence, these response were self-limiting - they enabled us to save ourselves when a wooly mammoth charged and then, because of built-in feedback loops, they shut off. Neural firing and chemical activity returned to baseline levels. Today, the stress response has become a serious threat to the health of many people because its has come to be provoked by many events in our daily lives and it has become a chronic way of responding for many people.

Biologically, we were designed to live as hunter gatherers, a lifestyle that is very different from what we now have. Now, for many people, the hunter's fight or flight response is provoked by an angry boss, a frightening drive on a high speed freeway, a notice from the IRS, a bad hair day, a summons for jury duty, and on and on. Our nervous systems are in a constant state of hyperexcitability and the stress response, with all its immune system effects, is provoked over and over again. When this happens, not only are immune functions weakened, but the adrenal glands become exhausted, leading to symptoms of weakness, dizziness, tiredness, headaches, memory problems, allergies, and even more serious illnesses.

In the last decade, even the mainstream medical community has come to realize that stress, other mental states, and even personality patterns are linked to the development of many, many illnesses and to the recovery from even more including cancer, arthritis, diabetes, asthma, lupus, allergies, multiple sclerosis, inflammatory bowel disease, psoriasis, chronic fatigue syndrome, and all kinds of infections to name but a very few.

Psychoneuroimmunology has given us some bad news about the “stress-full” lifestyles that so many of us live. At the same, however, it has brought some very good news. The good news is that the body knows and can re-establish a more adaptive way of responding. Shortly after Selye began talking about the stress response, Herbert Benson, a Harvard cardiologist, began reporting on the Relaxation Response. He “discovered” this response while studying the physiological changes that occur in people practicing transcendental meditation. The relaxation response also involves communication between the brain and other body systems, again through the hypothalamus, and is characterized by the following events:


-reduced blood pressure

-reduced respiratory rate

-reduced heart rate

-reduced fuel consumption

-reduced blood flow to skeletal muscles

-reduced muscle tension

-reduced perspiration


The relaxation response has been found to counter many of the negative physiological effects of stress and to enhance immune system function and the body's capacity for healing. Many other interventions and lifestyle changes have also been shown to have similar beneficial effects. These include progressive relaxation, mental imagery, breath work, proper diet and exercise, biofeedback, massage therapy, aromatherapy and expressive therapies, counseling, and many others.


The findings in psychoneuroimmunology have exciting implications for the practice of aromatherapy, which offers the possibility of improving health through direct effects on immune function, as well as through the mind/body connection. The following statement by Patricia Davis highlights the versatility of essential oils in directly enhancing immune system function:

Essential Oils can support and strengthen the immune responsein two ways: by directly opposing the threatening microorganismor by stimulating and increasing the activity of the cells involved.A number of essential oils combine both these actions, for example, Lavender, Bergamot, Eucalyptus and Rosemary all act against a widevariety of bacteria and viruses while at the same time increasing theimmune response. Rosemary and Geranium support the adrenal glands in their action and are also stimulants f the lymphatic system. Black Pepper andLavender have a beneficial action on the spleen. (Patricia Davis, AromatherapyAn A-Z, 1988, pg.173).

Added to Davis' statement is the fact that judicious use of essential oils to combat routine bacterial and viral infections can help avoid the immune weakening effects of prescription antibiotics.

The use of essential oils in cases of immune system over-activity has been explored by Michael Alexander, who states:

EO inhalation therapy is effective in treating the responses to inflammationthat are present in adverse immune reactions like asthma and autoimmunedisorders. The desired effect is immunosuppression. Immunosuppressionis a term used to describe therapeutic intervention which attempts tosuppress immune responses that are overactive, persistent, and cause harmto the body (Alexander, Michael, “the prophylactic use of essential oil inhalation therapy and its mechanisms of action in the treatment of respiratory hyper-sensitivity reactions. Aromatherapy Journal, 2002, 11 (3&4), pg. 19).

In this article, Alexander goes on to discuss essential oils which inhibit the inflammatory process, among them lavender, peppermint, rosemary, and blue chamomile.

In addition to acting directly on immune system function, aromatherapy has the potential to strengthen and normalize the immune system and improve health through the mind/body connection by reducing stress and promoting relaxation. In this application, the physiological effects of essential oils are combined with the well known stress reducing effects of massage and touch.


In addition to evolving as physical beings, the human species is also evolving as spiritual beings. As our subtle bodies evolve, we develop increased sensitivity to the energetic vibrations that surround us and there is increased exchange through non-physical channels between the subtle bodies and the physical body. In this way, the immune system and other aspects of our physical health become a sort of visible feedback tool. As we observe the effects of mental states on the body we learn not only what is good for us as physical beings but also what is good for us as spiritual beings - what we are intended to be. PNI studies have shown us that stress and emotions like depression, anger and fear have adverse effects on our physical bodies. There is good reason to believe that “negative” emotions in general have negative health repercussions and it seems likely that if we developed studies to examine the immune and general health effects of such negative emotional and spiritual states as bigotry, sexism, intolerance and hatred in all its forms we would find that holding these patterns in the heart and mind makes us sick.

Vibrationally, we may consider anything with a disharmonious or “negative” resonance to be an “antigen”, a pathogen that invades the mind, body and spirit and provokes a defensive response. Negative thought forms and emotional states literally act as antigens within both the physical and subtle bodies - up to a point our innate defenses will “fight” these pathogens off but this fight weakens us if it is continual and eventually we become sick in body and exhausted in spirit. Our vital essence is depleted and we simply don't have the energy for creating a healthy and fulfilling life. This is a problem of epidemic proportions in modern societies yet you will never find a diagnosis for it in any medical text.

It is important to be aware of the vibrational quality of the thought patterns that we hold, as well as of the environment around us. The culture that we live in is one in which we are all exposed to a continual flood of negative thought forms: murder, violence, aggression, greed, materialism, terror, hatred. Dualism, which is basically a philosophy of separatism, is still the underlying concept that forms the basis of our society: rich and poor, black and white, male and female, them and us. We are also overwhelmed by other less obvious negative patterns in the form of attachments - to possessions, to power, to self-image and status. Just as you would not drink from a stagnant pool for fear of bacterial infection, be careful what “drink” up from the world around you. All of these thought forms are pathogenic to body, mind, and spirit; holding them in our consciousness exhausts us and squanders our energy.

Possibly the most promising aspect of holistic/alternative therapies lies in their exploration of the subtle and multi-faceted energies that act on human beings at many levels. This exploration is leading to the development of a field called Vibrational Medicine. Although some of this knowledge is ancient, it has been lost in mainstream medical practice. As it returns to us and is expanded, we are discovering radically different technologies to improve our health and help us reach our full potential. These two things are inter-related; just as survival is a biological imperative, realizing one's potential is a spiritual imperative. As strong as the biological imperative is, the spiritual imperative takes precedence over it - to be healthy in the body, as well as in the mind and spirit, it is necessary to remove blocks that hinder the spirit in its path towards fulfillment. The real power of the holistic practitioner lies in his or her ability to see all of this at once and to share that vision with others in a way that brings body, mind and spirit into accord. This is the true art of healing.


Joie Power, Ph.D. practices as a Wellness Consultant, Healer, Reiki Master, and Personal Development coach. She is a retired neurobehavioral specialist with training in the neurological aspects of olfaction (smell) and emotional functioning, as well as psychoneuroimmunology, mind/body approaches, dreamwork, and aromatherapy; She provides consultation to individuals, physicians and holistic practitioners and is the founder and owner of  The Aromatherapy School . To learn more about individual consultations workshops and educational presentations, contact Dr. Power through her website The Aromatherapy School.

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