Nature and Nurture in Personality and Psychopathology

A Guide for Clinicians

Joel Paris

• Editorial: Routledge
• Año: 2022
• ISBN:
  9781000542776
• Edición: 1
• Categoría: Psychologie
• Categoría: Persönlichkeit in der Psychologie

Psychiatry and clinical psychology have long been divided about the roles of nature and nurture in the pathways to psychopathology. Some clinicians offer treatment almost entirely based on neuroscience. Some psychologists offer psychotherapies almost entirely based on the impact of environmental stressors. Paris argues for a balanced middle ground between nature and nurture in human development. This book reviews and integrates research showing that the key to understanding the development of mental disorders lies in interactions between genes and environment. It explores why personality is a key determinant of how people respond to stress, functioning as a kind of psychological immune system. This model represents a shift from overly simple and reductionistic constructs, based primarily on biological risks or on psychosocial risks in development. Instead, it offers a complex and multivariate approach that encourages a broader approach to treatment.

This book is essential for all mental health clinicians who are interested in understanding the roles of nature and nurture in the development of psychopathology.

1 Defining and Measuring Psychopathology

DOI: 10.4324/9781003156215-1

Separating Normal from Abnormal

Psychopathology refers to behaviors, emotions, and thinking patterns that are associated with significant psychological impairment. Yet like many other scientific terms in psychology, psychopathology has fuzzy boundaries. It can be very difficult to separate what is abnormal from what is normal (Frances, 2013). At what point do symptomatic responses to the challenges people face in the course of a human life merit formal diagnoses?

It is easy to forget that in the course of a normal life, most of us have periods of significant suffering. Grief is a good example—it produces dysphoria and affects functioning while it lasts, but is not the same thing as depression, and need not be considered an illness (Wakefield, 2012). Many of the symptoms that clinicians see, such as anxiety and depression, can be viewed as exaggerations of potentially adaptive responses to the environment (Nesse, 2019). And some are just part of the human condition.

Quite a few experts, inside and outside of psychiatry, see current diagnostic systems, whether based on the DSM-5 (American Psychiatric Association, 2013), or the International Classification of Diseases (World Health Organization, 2018), as suffering from serious problems. I agree. When we divide psychopathology into categories, mental disorders lack specificity (i.e. they overlap with each other). Moreover, diagnoses have no validating biological markers like those found in most medical conditions.

While most academics understand these problems, clinicians – and many of the patients they treat – sometimes seem to be “in love” with categorical diagnoses. The main reason is these categories provide hope that suffering can be understood and treated. But while that is often the case, many of the diagnoses we use are not scientifically valid. They may be given to patients on the basis of a rapid evaluation, and suffer from an availability bias, i.e. using whatever category most easily comes to mind, or from a confirmation bias, i.e. actively looking to confirm a diagnosis and then “finding” it (Kahnemann, 2011).

Working for two hospitals, I carry out about 500 consultations a year. I am constantly amazed at the level of confidence that people have in the diagnoses they have received from other professionals. Many are relieved to be told about the name of their condition, assume that the category is well researched, and believe they can benefit from a known method of treatment. Thus, patients proudly announce: “I have been diagnosed with x” as if they had been placed in a category as valid as tuberculosis or heart failure. In some cases, as in psychoses, a certain level of certainty is justified. But, all too often, patients only show some of the features of these constructs. And since diagnosis often serves, for better or worse, as a guide to therapy, treatment choices may also be problematic.

The root of the problem is that diagnoses in psychiatry are almost entirely symptomatic. Until we know more about the causes of psychopathology, we have little choice but to classify patients on the basis of symptoms. Yet doing so can only be, at best, an approximation. (Note that general medicine has its own purely symptomatic labels, such as irritable bowel syndrome or migraine.)

Diagnosis can be a valuable exercise if it provides some measure of guidance for treatment choices. That can often be the case for the most severe mental disorders, such as schizophrenia, bipolarity, or melancholic depression. But even when labels are useful, we need not believe in the reality of current diagnoses. It would be better if we admitted how imprecise they are, and to avoid attributing them the level of validity one finds in other medical specialities. Diagnoses can best be seen as a language: a convenient way to summarize and communicate basic information about patients.

There has been no lack of criticism of psychiatric diagnosis over the years. Unfortunately, much of it has been aimed at the wrong targets. The idea that mental illness is a myth, or a social construct, is absurd. But its popularity can be explained in several ways. One is that being mentally ill carries a stigma. Moreover, people are so afraid of mental illness that they want to deny its existence. Still another is that the treatment of psychopathology can be difficult and uncertain.

Some advocates of “anti-psychiatry” (e.g. Whitaker, 2002) seem to believe that even the most severe mental disorders are variations on normality that may not even require medical treatment. This view can only be described as irresponsible. I invite those who say such things to spend an evening in a psychiatric emergency room to see just how sick psychiatric patients can be. The more severe mental disorders are still not well understood, but are as valid as most conditions in neurology and internal medicine.

A famous study by Rosenhan (1973), published in the prestigious journal Science, has long been used to debunk psychiatric diagnosis. Its method was to send eight volunteers to pretend to be psychotic (describing auditory hallucinations) in emergency rooms. The reported results were that these pseudo-patients were admitted to hospital and treated. This finding is still touted as showing that psychiatrists cannot tell the difference between sane and insane people. Actually, all this study actually showed was that patients can fool physicians by faking an illness. Quite a few are known to fake physical illness in the same way.

The real story behind the study is even darker. As Cahalan (2019) showed in a book-length investigation, Rosenhan was a fraudster who invented most of the data he reported. There were at most two people (including Rosenhan himself) who did the pretending. The others were imaginary.

This is not the first or the last example of fraud in science. But an uncritical response to Rosenhan's paper did incalculable damage to the treatment of patients with serious psychopathology. Even today, this study is quoted in psychology textbooks. It plays much the same role in mental health research as the false claims published in Lancet some years ago claiming that vaccines cause autism.

The critics of psychiatric diagnoses have often misdirected their commentaries by focusing on the most severe (and scientifically valid) categories of illness. Schizophrenia and bipolar disorders are clearly diseases of the brain. The critics would have done better to focus on the conditions that are most common in community populations. But these are the categories that lack well-defined boundaries, and that are all too often over-diagnosed. The list includes major depression, so-called “bipolar spectrum” disorders, attention-deficit hyperactivity disorder, post-traumatic stress disorder, autism spectrum disorder, as well as (I am sorry to say) my own area of personality disorders (Paris, 2020a). It is not that the problems these labels describe are imaginary – they most definitely are real. It is the way disorders are classified that is problematic. We do not know enough to do that properly. An unjustified certainty about classification can lead to bad or unnecessary treatment.

For all these reasons, there still is a fundamental difference between psychopathology and diseases in medicine. Yet many leading researchers disagree with that conclusion (Insel and Qurion, 2005). The current climate of opinion rejects any separation between the realm of the mental and the realm of the physical. In one sense, I agree – like almost everyone who have been trained in scientific medicine, I reject any kind of dualism between mind and body. But the difference is that mental health care is about dysfunctional people, not dysfunctional organs. Of course, disorders of the mind do produced changes in the brain. But they may require methods of treatment that are not necessarily medical, and that take psychosocial issues and life histories into account. Even in medicine, there is a need for humanistic models that aim to understand patients, and not just their diseases.

History provides a perspective on these issues. Psychiatry began in the 19th century as a sub-specialty of neurology. But in the 20th century, partly due to the rise of psychotherapy, it became a specialty on its own. Insel and Quirion (2005) argued that this separation was a mistake. They followed the mantra that all mental disorders are brain disorders, and that psychiatry should become a sub specialty of neurology defined by the clinical application of neuroscience.

I do not agree, and shudder to think what kind of treatment mentally ill patients would get if neurologists took over their care. The world view of these two specialities is very different, and pathology that primarily affects the mind (thoughts, emotions, and behaviors) belongs to a different conceptual universe from diseases that primarily affect sensorimotor systems. Mental illnesses are not associated with lesions or biomarkers, and although they may be eventually identified, I doubt that any will be found soon. That is what makes psychopathology very different – albeit much more mysterious – than general medicine.

Categories and Dimensions of Psychopathology

As discussed in the Introduction, this book will preferentially use the term psychopathology to describe the domain of mental disorders. This term allows for a quantitative and dimensional alternative to current systems that use qualitative categories.

Categorical systems do reflect the way that people naturally think, and have long been the basis of medical diagnosis. It is a defensible approach for schizophrenia and bipolar disorder. Yet, at this point, we just do not know enough about other forms of psychopathology to uncritically adopt a categorical approach to diagnosis. It is possible that categories will become more useful in the future when we actually understand the etiology of severe mental disorders. However, current diagnoses fail to do justice to the problems we see in the clinic, which tend to center around common disorders with symptoms of depression and/or anxiety. These clinical features strongly overlap, and are often associated with other categories, such as substance abuse. The result is that it is not uncommon for patients to be given 3, 4, or 5 diagnoses. That kind of diagnostic practice is not coherent, and it is not a useful guide to management.

At our current level of knowledge, there are advantages to using dimensions that are “transdiagnostic” and apply a quantitative approach. That cannot be done by following a DSM manual and counting up symptoms. The problem is that we do not know the weight of each feature in relation to the diagnosis. To deal with this problem, we need psychometrics, a method pioneered by research psychologists. Based on self-report drawn from questionnaires, or by structured clinical observations, psychopathology can be described with scores that are subject to the statistical methods of factor analysis. Doing so creates a set of continuously variable and scorable dimensions.

The search for a better system is driven by the weaknesses of the one we are currently using. After 40 years, the most important diagnoses in DSM-5 still lack reliability, with major depression doing no better than a low reliability (kappa coefficient of 0.2 between clinicians) in a field trial (Regier et al., 2013). As any researcher will tell you, one cannot have validity without reliability.

Yet there are advantages and disadvantages to seeing psychopathology as a set of continuously varying dimensions or as a set of categories. The most severe disorders do seem to fit into a categorical medical model of classification. But the lack of validity for most current diagnoses is notable. Many, if not most, of the conditions that clinicians see are not separate diseases, but descriptions of characteristic symptoms that group together into syndromes.

A good example is major depression, which is not necessarily that “major”. The bar for diagnosis is set very low, and anyone who has symptoms for two weeks or more can receive it. Moreover, clinical depression describes a clinical picture that can derive from very different etiological pathways, and which takes different forms that require different methods of treatment (Parker, 2007). There are severe forms of depression that should be treated as life-threatening illnesses that require urgent medical treatment. However, the mild and moderate forms of depression that clinicians see might make more sense as a dimensional score, as opposed to a category that leads many clinicians to automatically conclude that medication is required for every patient, a view that is not supported by good evidence.

We may still need to retain categories that describe disorders which, even if they have fuzzy boundaries, have unique clinical features that can guide therapy. This applies to classical cases of schizophrenia or bipolar disorder, whose etiology reflects a large biological component (Zwicker et al., 2018). We may also want to retain categories of disorder that have important psychosocial causes, such as anorexia nervosa (Zipfel et al., 2015) or borderline personality disorder (Paris, 2020b), and which also point to prescribing specific treatment methods.

Yet, as knowledgeable clinicians recognize, the way that disorders are described in current manuals is at best approximate, and at worst unsatisfactory. Only the most severe disorders can be diagnosed in the same way as medical conditions, and even then, they either lack biomarkers, or have markers more closely related to traits than to categories of illness. For example, even the highly researched categorie...

Índice

• Cover
• Half Title
• Title Page
• Copyright Page
• Contents
• Introduction
• 1 Defining and Measuring Psychopathology
• 2 Personality and Psychopathology
• 3 What Genes Can and Cannot Tell Us
• 4 Neuroscience: Triumphs and Limitations
• 5 Childhood Adversities and Adult Functioning
• 6 Resilience: Surviving a Bad Childhood
• 7 Nature–Nurture Interactions
• 8 Problems with Causality
• 9 Implications for Psychotherapy
• 10 Implications for Prevention and Management
• References
• Index