Dualism and the 'Difficult Patient': Why Integrating Neuroscience Matters

Abstract

Patients with psychiatric illness present a unique challenge to clinicians: in contrast to the traditional medical model, in which patients are conceptualized as being stricken by a disease, patients with certain psychiatric illnesses may seem complicit with the illness. Questions of free will, choice, and the role of the physician can cause clinicians to feel helpless, disinterested, or even resentful. These tensions are a lasting legacy of centuries of mind-body dualism.

Over the past several decades, modern tools have finally allowed us to break down this false dichotomy. Integrating a modern neuroscience perspective into practice allows clinicians to conceptualize individuals with psychiatric illness in a way that promotes empathy and enhances patient care. Specifically, a strong grasp of neuroscience prevents clinicians from falling into the trap in which behavioral aspects of a patient’s presentation are perceived as being somehow separate from the disease process. We demonstrate the value of incorporating neuroscience into a biopsychosocial formulation through the example of a “difficult patient.”

The Dilemma of the “Difficult Patient”

Hippocrates is commonly considered the father of modern medicine. His work defined the foundations of the profession: diseases are a natural process, rather than a divine affliction; the role of the physician is to identify the biological cause and to facilitate a corresponding treatment. Across the centuries, an increasing number of medical successes – from antibiotics to life-saving surgeries to modern precision medicine – have all reinforced this approach.

This same model remains foundational to training: from the first day of medical school, students are taught basic science with the promise that they will ultimately apply this knowledge to diagnose and treat their patients. Armed with empathy and optimism, they arrive on the wards, ready to leverage years of training to pursue their goal from the outset – to help suffering patients.

But something happens. A disturbing research finding is that physicians may actually experience a decrease in empathy throughout medical training (1). While the reasons for this are undoubtedly multifactorial, one mechanism may be through their interactions with a subset of complex – or “difficult” – patients.

Take for instance, Mr. A, a 39-year-old gentleman with a history of intravenous heroin use, admitted to the internal medicine service for the treatment of infective endocarditis. Mr. A is well known to the residents and attendings on the service due to his frequent admissions, demands for pain medication, verbal outbursts, and tendency to leave against medical advice prior to completing his course of intravenous antibiotics. Physicians describe Mr. A’s complaints of radiating neck pain, attributed to an old motor vehicle accident, as “lacking an identifiable organic source.” His uncooperative attitude is frequently documented as “manipulative” or “indicative of a pathological temperament.” Not surprisingly, the medical staff feels frustrated with their inability to help Mr. A, to the point where they often question the amount of resources that have been dedicated to someone who continues to make such self-destructive choices. Behind closed doors, they may disparagingly mutter that “this is all in his head.”

The third-year medical student rotating on the service may feel stuck. On one hand, Mr. A’s infectious and immunobiological issues will align well with the student’s training. But the patient’s affective and behavioral dysregulation may be baffling. Because these problems are “lacking an identifiable organic source” they do not readily fit within the basic framework of the medical model – and, accordingly, they may strand the student outside the traditional role of doctor, leaving them feeling helpless and frustrated.

Haunted by Descartes’ Ghost

To understand why something like a substance use disorder and its sequelae are so easily relegated to “lacking an identifiable organic source,” it is helpful to look back to 17^th century philosophy and, specifically, to the work of Réne Descartes. Descartes promoted the idea that mind and body were separate entities and that mental activity arose from a substance distinct from the body (2). This idea is now referred to as “Cartesian Dualism” (in contrast to more modern perspectives on the problem [3]). While Descartes had his contemporary detractors, his broad influence as it applied to medicine would go largely unchallenged for the next 250 years.

In the 19^th century, new ideas about natural selection and conservation of energy often seemed incompatible with Cartesian Dualism. This inspired a new generation of researchers – from Charcot to Broca to Babinski to Kraeplin– to try to bridge the mind-body divide (4). One such individual was the young neurologist, Sigmund Freud. With training in both neuroanatomy and neurophysiology, Freud seemed to be in a perfect position to integrate the biological with the psychological (5). But when the scientific tools of his day proved inadequate for such an undertaking, Freud’s work shifted to exploring psychological models in greater depth (6). His work developing psychotherapy and psychoanalysis set in motion a split – brain from mind – that, following the advent of EEG, would ultimately lead to the separation of neurology and psychiatry (7). Ironically, for someone who set out to integrate the field, he may have inadvertently exacerbated the severe dualism that would become cemented in psychiatry for another hundred years.

Psychoanalytic thought largely dominated the field until the 1950s, when psychopharmacology took the world by storm. While one might have hoped that these new tools could have been integrated into a unified psychiatry – psychodynamic theory and biology side by side – sadly, it proved to be a wedge.

On the biological side, Schildkraut (1965) and van Rossum (1966) put forth their hypotheses that affective and psychotic disorders were related to aberrant levels of neurotransmitters that could occur independently of a psychological or environmental etiology. Advances in pharmacological science allowed both Schildkraut and van Rossum to extrapolate knowledge of drug mechansims into hypotheses of disease mechanisms. If imipramine could treat depression by increasing catecholamines, and reserpine could exacerbate depression by depleting catecholamines, then it followed that depression was a disease of catecholamine deficit. Psychiatry had finally identified a set of biological targets: this ushered in a golden age of research in which drugs were not only treatments but tools to investigate the mysteries of the brain.

But not everyone was impressed. The British psychiatrist RD Laing had little interest in catecholamines. He, along with many other experts of the time, believed that psychiatric illnesses were not biologically driven processes; rather, they were emergent properties of complex psychological, social, and family dynamics (this was at the same time as the “schizophrenogenic mother” model) (8). For these reasons, he did not believe that psychiatrists should adhere to the standard medical process of eliciting a chief complaint, conducting a history and examination, testing, diagnosis, and treatment. In fact, Laing ultimately coined the term “medical model” in order to distinguish the work of psychiatrists from that of the rest of medicine (9). Looking back, this is an astonishing moment in the history of our field – perhaps the height of the division between physicians of the “mind” and physicians of the “brain.”

In the wake of this fractious debate, George Engel offered a strong corrective: the biopsychosocial model (10). Rather than splitting and separating, the framework acknowledges and embraces the interconnectivity between a patient’s illness, their social situation, and their behavior. On one hand, Engel’s solution was the definition of scientific elegance: both simple and applicable. But it also served as a lightning rod for criticism (11) – for being overly reductionistic or, paradoxically, for unduly emphasizing the separateness of each perspective. The problem stemmed from a lack of mechanistic understanding – it’s all well and good to say that the different perspectives are intertwined, but the devil is in the details – how does it actually work? Until recently, these questions were unanswerable. It was a model before its time.

Modern neuroscience is increasingly providing the crucial data to bridge this divide and to demonstrate the nuanced ways in which bio-, psycho-, and social processes are all mediated through the brain. For example, a large body of literature has demonstrated the ability of psychotherapy to alter brain activity in a way that promotes improved emotional regulation (12). Early social experiences, such as a history of abuse and/or neglect, can blunt the brain’s response to rewards in the environment (such as money or social praise), while increasing sensitivity to drugs of abuse (13,14). A burgeoning literature is illustrating that one key mechanism through which experiences influence brain function is through alterations in gene expression, otherwise known as epigenetics. This was elegantly demonstrated by Michael Meaney’s research group, who showed that variations in maternal care in rodents altered methylation of key genes related to the stress response and anxiety-like behavior (15). As concluded by Eric Kandel, winner of the 2000 Nobel Prize in Medicine and Physiology for describing how learning is dependent on changes in gene expression in neurons, “all of ‘nurture’ is ultimately expressed as ‘nature’” (16).

The Modern Enlightenment

The Age of Enlightenment was thought to begin with Descartes. It is ironic, then, that one of his most influential ideas has pervaded medicine in a way that prevents us from understanding patients in a scientific manner. The true challenge for clinicians today is to be able to thoughtfully integrate a patient’s experience beyond vital signs and crude diagnostic tests. For example, coming back to the case of Mr. A it would be interesting to learn more about his family and early life experiences. Heritability of substance use disorders can be as high as 70% (17). Thus, while environmental factors obviously play a role, it is crucial to keep in mind that these disorders may have a stronger genetic component than breast cancer (18), coronary artery disease (19), type 1 diabetes mellitus (20), and most other medical illnesses. As described above, a history of childhood adversity is associated with brain changes that can increase vulnerability to addiction. The prominent role of both genetics and early life experiences should challenge our instinctive tendency to view addiction as a choice. Careful investigation into his pain might reveal that Mr. A’s previous injury led to long-term plasticity in his nervous system that has resulted in chronic pain (21). Mr. A’s use of exogenous opioids may have also created a state of opioid-induced hyperalgesia via increased release of excitatory neurotransmitters (22). The ability of opioids to directly suppress the immune system may also contribute to his current infection (23).

Approaching Mr. A’s case from a fully integrated biopsychosocial perspective will not necessarily cure his addiction or prevent him from leaving the hospital against medical advice. However, incorporating neuroscience into the formulation allows his clinicians to appreciate that his illness is a medical condition that is within their scope of practice. In turn, this understanding serves to invite empathy, to promote continued inquiry and discourse, and it leaves less room for helplessness and resentment. Lastly, it may allow us to advocate for our patients by reminding our colleagues that while some symptoms may be “in their head”, it is a head that houses the body’s most complex organ.

Multiple Choice Questions.

1. Cartesian dualism refers to

1. A mathematical theorem used in computational psychiatry

2. The idea that biological, psychological, and social elements of an individual’s illness are interconnected

3. A phrase coined by Freud to describe opposing influences on behavior

4. The idea that mind and body are separate entities, made of distinct substances

5. A neurobiological concept that explains paradoxical responses to opioid receptor agonism based on dose.

2. Biological models in psychiatry that emerged in the 1960s were predicated on

1. Comparisons of patients that were vs were not responsive to psychoanalysis

2. Research in the neuroanatomy and neuropathology of individuals with psychiatric disorders

3. The observation that both insulin and electroconvulsive therapy could induce seizures

4. Extrapolating pathophysiology of illness from the mechanisms of drugs that treated the illness

5. The application of mendelian genetic principles

3. The origin of the term “medical model” can be traced to

1. R.D. Laing’s attempt to distinguish the methods that physicians use in psychiatry from those used in the rest of medicine

2. Hippocrates’ work separating the practice of medicine from theology

3. William Osler’s The Principles and Practice of Medicine

4. George Engel’s “The need for a new medical model”

5. Eric Kandel’s research that resulted in his Nobel Prize in Physiology and Medicine

4. A formative step towards a modern integrative approach to psychiatry can be attributed to

1. Descarte’s ideas on the relationship between mind and body

2. Lang’s work on the role of family and social determinants of schizophrenia

3. Meaney’s research on epigenetics

4. Schildkraut’s catecholamine hypothesis of affective disorder

5. Engel’s biopsychosocial model.

5. Which of the following is true regarding the neurobiology of substance use and chronic pain?

1. The development of chronic pain following injury is due to long-term potentiation in pain circuits

2. Opioid-induced hyperalgesia develops in response to excess GABA inhibition of opioid-receptor containing neurons

3. Variability in the propensity to develop opioid use disorder is mainly due to access to substances and socioeconomic variables rather than genetics

4. Early life stress results in changes to the dopamine system that decrease sensitivity to cocaine while increasing sensitivity to opioids.

5. Opioid-induced increases in immune activity can result in chronic pain and inflammation.

Learning Objectives.

After reading this article, you will be able to:

1. Appreciate historical factors that have contributed to dualism in psychiatry

2. Appreciate the value of an integrative perspective.

3. Describe how psychological and social factors integrate with a neuroscience perspective in substance use disorders.