Understanding Diabetes through Psychoneuroimmunology

Diabetes mellitus is a very serious illness which does not differentiate with age and compromises around 6.4% of the world’s total population[i]. Although there is no precise explanation for the direct causes of it, today’s scientific community has established an understanding of the effects and mapped multiple causes that are linked to the origins of the disease. To understand the topic in question, we have to primarily define the illness under study. Diabetes Mellitus (as defined by the ADA) is “a group of diseases characterized by high blood glucose levels that result from defects in the body’s ability to produce and/or use insulin”[ii]. There are two main types of diabetes: (I) Type (1) Diabetes Mellitus; also referred to as T1DM, is the second most common type of diabetes in the world and haunts 10% of all diabetes victims. It is a form of DM that develops rapidly and targets mainly youngsters through the form of an autoimmune attack which destroys insulin producing pancreatic β-cells. T1DM’s classical symptoms are polyuria (increased urination), polyphagia (increased hunger), and polydipsia (increased thirst), unexplained weight-loss, and fatigue[iii]. (II) Type (2) Diabetes Mellitus; also referred to as T2DM, is the most spread type of diabetes which holds hostage 90% of the total reported diabetes cases. T2DM is the outcome of insulin resistance, a state in which cells fail to properly manifest insulin, sometimes conjoined with a complete deficiency in insulin. T2DM’s classical symptoms are similar to those of T1DM along with blurred vision, weak ability to heal and to resist infections. Moreover, T2DM is quite slow in manifestation and may take years to actually cause the patient to question his health. Both types pose a credible risk on a person’s life if left untreated, and are a result of the inability of the body on a cellular level to cope with itself and provide itself with the proper glucose intake, leading to an increase in the person’s glucose level.


As previously noted, the scientific community has not yet defined the underlying cause that paves the way to DM. Different scientific opinions have attempted to shape our understanding, while all scientists agree on the result; the scientific society today is confronted by different conflicting theories, each of which is highlighted with its own achievements and proponents fighting to establish credibility of their purports. The three main scientific methods today attempting to explain what causes DM are the Biomedical model (BM), the Biopsychosocial model (BPS), and Psychoneuroimmunology (PNI).


While the former model (BM) provides us with certain explanations that may be considered within certain circles to be “outdated” due to the model’s neglect of social factors, both latter models (BPS & PNI) do agree that the psyche (mind) has an important role in triggering, developing and marginalizing the illness itself. Indeed, the latter models do acknowledge the facts that the biomedical model asserts; however, they (BPS & PNI) take a step further in analysis, and claim that the external environment (the surrounding) influences the internal one (the human body). Through understanding the above models, we also conclude that the two latter models; (PNI and BPS), relate and that both are branches of a single larger model, which employs each to describe the mind-body interaction on a cellular (PNI) and holistic (BPS) scale. To gain perspective towards the issue of diabetes, one must pose the following questions: Primarily, what defines health? What causes diabetes? Does every day stress affect the immune system? If stress does affect the immune system, then how does that change take place? Does chronic stress encourage persistent bodily and immunological dysregulation? Can the management of stress and the variation of its immunological and endocrine effects alter or cure disease? Has the scientific community conducted any valid research that could help address these clinical questions?


Defining “Health” and the Basic Models

“Health” is a term that has been constantly reshaped to fit our developing theories that define the state in which a human entity is considered to be in its most functional and productive form. According to the WHO, health is defined as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.”[iv] With that being said, it is then realized that the contemporary scientific community bases its work on a holistic model that attempts to clarify the nature of diseases not only through explaining a failure in maintaining “health” by identifying invasive organisms attempting to thrive and survive by victimizing a different organism; (such as the case of viruses and bacteria), but also by understanding the environment of the victimized organism which lead to the failure in maintaining “health”. This may also be interpreted as an inclination in opinion of the majority of medical practitioners and experts in favoring the BPS model opposed to the BM model.


The Biomedical (BM) model is “a conceptual model of illness that excludes psychological and social factors and includes only biologic factors in an attempt to understand a person’s medical illness or disorder.”[v] It is a reductionist model that perfectly encompasses allopathy[1] by equating the body to a machine via presuming that illnesses are due to abnormalities in bodily functions that require either repair or replacement. It is a model that perfectly embraces the application of Occam’s razor by only considering the simplest possible cause of illness and then introducing the cure (e.g.: to treat diabetes, we inject insulin (In the case of T1DM)). This model was developed in mid-nineteenth century, when scientists discovered bacterium and viruses and identified them as the cause of numerous diseases. The identification of the prior mentioned organisms led to the automatic breakdown of previously established models of ‘miasmas’ and supernatural belief systems which were held by prior generations. The result of this discovery was a gateway of exponential advancement in medical fields via scientific reductionism (which is why this approach is still highly considered in all medical fields); another result though was the disintegration and depersonalization of patient care.


The Biomedical approach remains hegemonic in the Western perception of treatment, however, a newer proposed model has been paving its way into the mind of scholars and practitioners ever since it was re-brought into spotlight by cardiologist Engel. Engel coined the term “Biopsychosocial approach” when he attempted to theorize in the 1960s a new scientific approach to understand heart disease. Engel showed that heart disease is intertwined with large variables of cultural, social, and psychological factors (such as smoking, diet, genetic vulnerabilities, poverty, and stress) that ultimately interrupt the cardiovascular system. The Biopsychosocial model (BPS) is a holistic model that “addresses the complexity of interactions between different domains of functioning and argues that it is the interactions of domains that illuminate important processes.”[vi]


Today, we have considerable evidence that the quality of our social relationships plays a serious role in shaping multiple physiological systems which include cardiovascular, immune, and endocrine systems[vii], [viii]. In a nutshell, the BPS approach sets a basis that the physical aspect is not the only thing that should be taken into consideration. It rather states that the physical feature is a function relatively managed via various aspects that include interactions, memes, and values that shape our physical selves either positively or negatively. While clinicians instinctively gave importance to biomedical, psychological and sociological constraints when attempting to supervise clinical issues, hard evidence required to formulate a paradigm shift within the medical realm was in general lacking.


Psychoneuroimmunology (PNI): It’s Definition & Timeline.

Psychoneuroimmunology (PNI) is a modern scientific approach which has been recognized by the medical community for the past quarter century, and is considered to be connected to the field of psychosomatic medicine, since it attempts to establish an understanding regarding the complex relationship established between the psyche (mind), the brain (neuro), and the immune system (immunology) versus their implications for health. In 1865, Claude Bernard; who is considered to be the father of modern physiology, used the term “milieu intérieur” to define the “interior environment” which was later used by Walter Cannon to develop the idea of homeostasis (meaning similar position). Cannon observed that any variations in the emotional state (e.g. anxiety, distress, etc…) were conjoined by the complete termination of gastric activities[ix]. These studies highlighted the interaction of psychological state with the sympathetic and parasympathetic responses which initiated the “freeze, fight, or flight mode”. In 1975, Robert Alder and Nicholas Cohen investigated the consequences of long conditioned responses in rats. The study reported that a stimulus via the nervous system directly affected the rat’s immune function. In 1981, David Felten discovered a network of nerves leading to blood vessels as well as cells of the immune system. Alder, Cohen and Felten’s discoveries provided one of the primary indications of how neuro-immune interactions occur, and led them to edit the revolutionary book “Psychoneuroimmunology” in 1981; which laid out the fundamental principle that the brain and immune system represent a single, integrated system of defense.


Studying DM under the Scope of PNI


Major studies have been conducted to understand Diabetes Mellitus (DM), and almost each and every one points out to the common causes which are stress, anxiety and depression. A stressor is “any stimuli that causes a nonspecific response in an individual, otherwise known as stress[x]. Stress is divided into two categories: “acute stress” and “chronic stress”; those two categories in return, result from two environments: the “external environment” such as work, relationships, etc… and the “internal environment” such as our thoughts, perceptions, and responses to people. On an emotional level, stress can lead to feelings of depression, anger, and anxiety[xi]; which according to the genetic, environmental and developmental influences and experiences are reflected in the individuality of each person[xii]. When a person is under stress, the body works overtime to help itself cope. This happens through multiple manners one of which is the release of hormones, such as epinephrine and adrenaline, both of which give an added amount of energy and concentration. In addition to hormones; the body also releases glucose from the liver, muscles and stored fat reserves so that the body will set itself under the “fight or flight” mode. The existence of stress has been a wonderful evolutionary add-on from Mother Nature that helped early humans to instinctively cope and decide on the proper course of action in the times that involved “predators and prey”. Chronic stress however, is a state of “continuous acute stress” in which the same “fight or flight” mode is available perpetually for prolonged periods of time due to ongoing anxiety and fear from the different aspects of life. With chronic stress, the body remains pumping hormones continually, the “fight or flight” response then renders obsolete; for neither a fight nor a flight is going to be of any help when your “enemy” is your own mind.


As previously explained, stress can be the cause of anxiety and depression, which according to an analysis conducted by the “Group Health Research Institute” on the “World Mental Health Survey” conducted by the WHO, is found to be tied to diabetes around the globe[xiii], [xiv]. According to the study, which has been published in the December 2008 issue of the Journal of Psychosomatic Research, community-based sample populations of 85,000 adults spread around 17 different nations were interviewed face-to-face in the rigorous standardized survey. The research found that people with diabetes tended to be about 40% more likely to have depression and 30% more likely to have some form of anxiety[xv]. Michael Von Korff, ScD, senior investigator at Group Health Center for Health Studies commented on the research by saying that “asking which comes first: diabetes, depression, or anxiety?” Is not even the right question since it falsely splits the body from the mind.” Von Korff explained that “although the relationship probably goes both ways, we think chronic physical and mental health problems are intertwined; they seem to influence each other continually.”[xvi]


Another Study entitled “Diabetes and anxiety in US adults: findings from the 2006 Behavioral Risk Factor Surveillance System”[xvii] studied a sample of 201,575 of which 20,142 were diagnosed with Diabetes. The research dealt with diabetes through the following controls: educational level, marital status, employment status, current smoking, leisure-time physical activity and body mass index, gender, age, and ethnicity. The analysis concluded that diabetes was significantly associated with anxiety in adults, particularly in Hispanics and young adults.


If the previously mentioned results are studied under the context of genetic variables relative to social influences; a perspective in which environmental factors are considered key agents of natural selection, then the concept that physiological and societal forces regulate gene frequency may therefore be observed as uncontroversial. The study would also be regarded as an ultimate proof to the “thrifty gene hypothesis” which was hypothesized by geneticist James V. Neel. In order to explain the dominance and incidence rates of obesity, hypertension, and T2DM in immigrants from developing countries[2] to developed countries are significantly higher than the majority of the population. The “thrifty gene hypothesis” suggested that across generations, individuals who managed to survive harsh situations and depravity of water and food, such as the case is in third world countries, passed along (a) gene(s) that accumulated energy. It was only through maintaining certain characteristics (such as increased insulin levels, low metabolism, excess fat storage, and insulin resistance) that individuals were likely to survive in these extreme conditions. Of course, this was of those particular advantages that Mother Nature selectively chose the “fittest” genes over the others in that particular environment. However, the migration from traditional lifestyles and environments towards a more sedentary way of life and calorie-dense environments and dietary supplies has, therefore, completely twisted the competitive advantage that those individuals once inherited to vulnerabilities through increasing the likelihood of obesity and T2DM[xviii].


A recent study in which researchers randomly assigned different participants either to integrated care groups or to usual care groups has highlighted the importance of integrating a dual medication system based on treating both depression and T2DM. The study which was conducted by researchers from the Perelman School of Medicine at the University of Pennsylvania, and whose results were published in the January/February issue of “The Annals of Family Medicine”[xix], concluded that the sample of patients who received an integrated care combined with brief clinical intervention to assist with the adherence to prescribed medical schedule, resulted with a 60% improvement in the blood sugar test results and noted that 58% of the sample patients reported reduced depression symptoms, relative to only 36% and 31%, respectively, of patients receiving ordinary medical care[xx]. Alongside, the March issue of “Diabetes Care” reported a new study conducted by Tilburg University. The study analyzed data from two multicenter cohort studies which included 2,704 patients who were hospitalized for myocardial infarction. The research concluded that during follow up, 439 patients died, and that 47% of the patients held both symptoms of depression and diabetes, as opposed to 14% of patients without both symptoms, 23% of patients with diabetes only, and 22% of patients with depression only[xxi].


Today, one cannot but express his/her support towards establishing a holistic model which takes the “humanity” of human beings into consideration. Indeed, modern biological studies have concluded that stress can “get inside the body” to affect the immune response[xxii]; and while the mechanical “biomedical” model does its job well by fighting pathogens which lead to DM, such as Cytomegalovirus infection and Coxsackievirus B, the “biopsychosocial” model does offer a deeper insight into the root causes of an “idiopathic” immune deterioration which might precede the viral infiltration into the victim’s body due to the body’s weak ability to fight any viral breakthrough, which in the end results in diabetes. Moreover, while the BM model offers limited solutions to specific diabetes cases such as chronic pancreatitis; the BPS model does prove to be effective in treating certain cases that underlie the cause of chronic pancreatitis such as the excessive use of alcohol and the body nutritional supply.





[1] The treatment of disease by conventional means, i.e., with drugs having opposite effects to the symptoms.

[2] When discussing developing countries, I am pointing to specific common features which are shared by the people of those countries. Mainly, common issues such as harsh environmental factors, and common traits such as slim bodies to facilitate long-distance movement due to the lack of mechanized mobility.


[i] http://www.worlddiabetesfoundation.org/composite-35.htm

[ii] http://www.diabetes.org/diabetes-basics/common-terms/

[iii] http://type1diabetes.about.com/od/type1diabetesbasics/a/symptomstype1.htm

[iv] Preamble to the Constitution of the World Health Organization as adopted by the International Health Conference, New York, 19–22 June 1946 http://www.who.int/bulletin/archives/80(12)981.pdf

[v] http://www.medilexicon.com/medicaldictionary.php?t=55643

[vi] Clinical Psychology (2002) 14 13-17

[vii] Multilevel Integrative Analyses of Human Behavior Social Neuroscience and the Complementing Nature of Social and Biological Approaches. Psychological Bulletin, 126; 829-43

[viii] http://psychology.uchicago.edu/people/faculty/cacioppo/jtcreprints/cbsm00.pdf

[ix] Bodily Changes in Pain, Hunger, Fear and Rage, 1915

[x] Elliott, G.R., Eisdorfer, C. 1982. Stress and Human Health. New York: Springer Publishing Company

[xi] McEwen, B.S., Stellar, E. 1993. Stress and the Individual: Mechanism Leading to disease.

[xii] ^Ibid

[xiii] http://www.ncbi.nlm.nih.gov/pubmed/19027447

[xiv] http://www.grouphealthresearch.org/news-and-events/newsrel/2008/081203.html

[xv] ^Ibid

[xvi] ^Ibid

[xvii] http://onlinelibrary.wiley.com/doi/10.1111/j.1464-5491.2008.02477.x/abstract

[xviii] Osei, K. (1999). Metabolic consequences of the west African diaspora: Lessons from the thrifty gene. Journal of Laboratory and Clinical Medicine, 133, 98-111.

[xix] http://medicalxpress.com/news/2012-01-concurrent-treatment-diabetes-depression-significantly.html

[xx] ^Ibid

[xxi] http://medicalxpress.com/news/2012-02-combo-diabetes-depression-post-mi-mortality.html

[xxii] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1361287/

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President of Freethought Lebanon and a diligent Lebanese civil society activist. A theoretical physicist by profession, Sami is passionate about both pursuing scientific truth and defending basic human rights in Lebanon and the Middle East.

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