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What is the relationship between the mind and the body? One of the first philosophers to investigate this complex question was René Descartes. In the 16th century, he developed the concept of dualism: the conviction that mind and body are made of two different substances.
The mind has no physical existence and therefore, takes up no space. The body, on the other hand, does take up space. Descartes was sure that there had to be a place in the brain where the material and immaterial substances communicate. He was convinced that the pineal gland is “the principal seat of the soul and the place in which all our thoughts are formed”.1
Today, we know that the pineal gland is an endocrine gland, responsible for melatonin production in response to the light-dark cycle, and thereby an important key player in the circadian system, our inner clock. But what is today’s understanding of the mind-body connection and where is the mind located?
I asked the Microsoft search engine’s Bing artificial intelligence (AI) the question and received the following reply: the mind is “a faculty that manifests itself in mental phenomena like sensation, perception, thinking, reasoning, memory, belief, desire, emotion, and motivation. The exact nature and location is unknown and debated about.”2 However, that does not solve the mind-body problem either. Modern approaches to the mind-body connection are physicalism, functionalism, embodied cognition and the extended mind.
The mind is identical with, or reducible to, the brain and is located in the brain or distributed across different brain regions. One example often cited by defenders of physicalism is the mental state of pain, which is identical to the activity of C‑fibres in the brain. In functionalism, everything that has a brain has a mind.
Telling people that their complex emotions such as joy or sorrow, but also their sense of self and personal identity, and even the concept of free will, is nothing more than the state of assemblies of nerve cells and molecules is not an answer to the mind-body problem most people can accept. As Francis Crick said in 1994 “You’re nothing but a pack of neurons”.3
The mind is not locked in the brain, but extends far beyond it, and is located in the body and its interaction with the environment, and our social interactions. According to defenders of this view, the brain is not the seat of cognition, and the brain does not process information in the same way as a computer.
The topic of mind and body connection is still a topic heavily studied by philosophers and neuroscientists. New publications find more and more proof for a connection of mind and body visible in brain processes. One recent study suggests that areas in the motor cortex have been found to play a major role in integrating planning and purpose (therefore, processes associated with the mind) and physiology, behavior and movement (processes associated with the body).4
Several examples reflect the connection between our mind and body. Epigenetics is one of those, and illustrates how the immaterial can influence the material. Epigenetics describes how environmental factors can change the way genes are expressed without altering the DNA sequence. (If you are interested in the topic of epigenetics, see this article by my colleagues titled “Epigenetic Testing – The Way Ahead for Life & Health Underwriting?”.)
One study found that children who experienced abuse or neglect have altered patterns of gene expression. This alteration led to an increased risk of developing mental and physical disorders in the long-term.5 Research has even supported the notion of transgenerational stress-induced epigenetics,6 meaning that the stressors a person’s grandparents endured may affect their vulnerability to certain mental and physical disorders and their resilience.7
A more familiar example is how stress affects the body. Inflammatory skin conditions, such as acne psoriasis and rosacea, have all been found to be worsened by chronic stress. But even if no inflammatory disease is present, stress affects our body in several ways. It is beneficial that the body reacts to stress with an immune response, preparing to fight potential pathogens, but if one is experiencing prolonged stress, this immune response is triggered chronically and the risk of developing chronic diseases will increase significantly.
The key player in this effect is cortisol. A very elegant system exists in the human body that aims to achieve a state of homeostasis when it comes to stress hormones, known as the hypothalamic–pituitary–adrenal axis (HPA axis). If cortisol levels remain high, this system will eventually fail and lead to an imbalance as the cortisol metabolism is decreased and cortisol levels remain high. This dysregulation of the HPA axis can increase someone’s risk of being obese, developing cardiovascular conditions and catching infections.8
What can individuals do to use the mind-body connection positively? Not all prolonged stressful situations can be avoided, but there are ways to prevent or partly protect the body from suffering long-term consequences of stress. One way that has been found to be beneficial is meditation, which can work as a mind-body mediator.9 It decreases stress, thereby improving overall mental health. Positive emotions have also been found to work as a protective shield.
The field of psychoneuroimmunology studies how the nervous system, the endocrine system and our immune system interact. Studies suggest that positive emotions boost the immune system. For example, participants who reported higher levels of stress and negative emotions, when exposed to a cold virus were more likely to become sick from the cold virus, compared to subjects reporting less stress and a more positive emotional state.10
Obviously, emotional states cannot always be steered to being positive and stress is a part of life. These studies, however, illustrate how important it is to find ways of decompressing and finding joyful moments in stressful chapters of life. But there is also a way to cheat the system: research has shown that if a person forces a smile, this may trick the brain into feeling more positive emotions.11
The gut-brain axis is another well-studied feature of the mind and body connection. We all know the expression of a “gut feeling”, and it is not for nothing that the gut is sometimes called the “second brain”. Gut health plays an important role in the adaptation to stress, and prolonged high cortisol levels have been shown to increase the permeability of the gut in animals12 and humans.13
Some studies have linked imbalances in gut microbiota to certain mood and anxiety disorders,14 which does not mean that poor gut health causes depression in a person who would have otherwise not been affected, but that gut health plays a role in people struggling with clinical depression. It has been found that the microbiome of depressed patients lacks bacterial diversity, which impairs their overall ability to react to stress.15
The over-representation of certain bacterial species has also been correlated to inflammatory processes.16 Furthermore, the conversion from the amino acid tryptophan into serotonin, a neurotransmitter thought to play an important role in several psychiatric conditions, has also been found to be diminished in a depressed study population.17 Links to clinical episodes of bipolar disorder and schizophrenia have also been reported.18
All-cause mortality and morbidity for those who have been diagnosed with a psychiatric illness are compromised. Even though suicide may be the trigger that comes to mind for most people, when discussing increased mortality in applicants with a mental health history, this is only a small part of the reason that life products are coming with a higher premium for this group of applicants.
If we take a look at disorders related to severe stress or traumatic events, such as post traumatic stress disorder, acute stress disorder or adjustment disorder, we see an increased all-cause mortality across these diagnoses.19 A study from Sweden,20 published in 2022, using the national patient register as its subject pool, wanted to find out whether the all-cause mortality in this study population was confounded by genetic factors, or whether the diagnosis itself played a major part in this.
The subjects were divided into three main groups. Group 1 was the “exposed group”, meaning those diagnosed with a stress-related disorder (with two sub-groups, one being compared to group 2 and one to group 3); group 2 were a sex-matched control group; group 3 were siblings of the exposed participants, who were unexposed themselves.
Participants in the exposed group were more likely to be divorced or widowed, had a lower family income level, a higher burden of somatic diseases and were more likely to have a history of other psychiatric disorders. The all-cause mortality was at its peak in the first year after diagnosis (3‑fold risk, HR 3.19 [95% CI, 2.87–3.54]) but stayed significantly higher compared to the control group (1.6‑fold risk, HR, 1.64 [95% CI, 1.60—1.67]).
Suicide played a large role in the higher all-cause mortality, but cardiovascular diseases were also significant. According to the authors, 70% of the deaths observed in their study population could have been potentially avoided, for example through proper treatment. The excess mortality was found to be largely independent of the genetic component they tested by including siblings. Possible reasons discussed for the increased mortality are the comorbid psychiatric illness found in more than a third of the exposed group; chronic psychological stress leading to a dysregulated immune system and possibly inflammation; and unhealthy coping mechanisms and behaviors, such as smoking, poor diet, and a lack of physical activity that then contributes to a higher incidence of (multiple) major chronic diseases in this subject group.
Diagnoses seen fairly often in underwriting are anxiety and depression. How do these diagnoses affect a person’s overall health? In 2007, a group of researchers wanted to explore the relationship between chronic physical conditions and depression and/or anxiety.21 Across the board, higher incidences of hypertension, arthritis, heart disease, chronic headache and multiple pain syndrome were observed. The odds ratio for someone with a non-comorbid depression (meaning without anxiety) for heart disease was found to be 2.0; for those with anxiety (and no comorbid depression) it was 1.9; and for someone who has both diagnoses, it climbed to 3.0.
For multiple pains, there is a 4.5‑fold increase in those who are affected by both depression and anxiety, compared to individuals who are suffering from neither. When underwriting disability, we should therefore be aware of this relationship between mind and body.
When underwriting an applicant who reports episodes of poor mental health or a medical history of psychiatric illness, it is important to keep in mind that mental health is directly connected to overall health, thereby influencing the mortality and morbidity of the applicant.
Studies have shown that the mind-body connection can affect someone’s health status and wellbeing in various ways. It is important to keep in mind that “physical” disorders should not be seen as separate entities from mental health and psychiatric diagnoses. If someone is reporting mental health issues, the risk of their developing a chronic, seemingly unrelated condition, such as heart disease or arthritis, is significantly increased, passively impacting their disability risk in the long run, even if the physical condition was not apparent at the underwriting stage.
