Chapter 1. Historical Overview

In the course of the nineteenth century, a discipline called “psychiatry” arose out of general medicine and neurology (Shorter 1997). Most practitioners were based in mental hospitals, where the majority of patients had psychotic illnesses. The biological perspective of these early practitioners was therefore entirely natural. In this way, psychiatry in the nineteenth century resembled the ideology of medicine as a whole. Although it was generally acknowledged that the etiology of mental illness was unknown, most clinicians assumed that, as had been the case for many other medical diseases, it was only a matter of time before anatomical or physiological causes of psychopathology would be found.

A number of attempts were made to identify these “constitutional” factors. However, psychiatrists in that century were largely unsuccessful in finding such abnormalities. Inspection of the brain in psychotic patients failed to show pathological changes. (There was one dramatic exception: the identification of general paresis as a tertiary manifestation of syphilitic infection.) In retrospect, we can see that failure was inevitable, given the primitive state of neurobiology at the time (brain imaging was a century away), but the inability of a purely medical model to provide a coherent explanation for psychopathology created an empty niche and led to very different pathways of research. In spite of their overall biological bias, clinicians in the nineteenth century had an interest in the psychological factors of mental illness and practiced early forms of psychotherapy (Ellenberger 1970). From the time of Philippe Pinel and the “moral treatment” of the insane, psychiatrists attempted to apply a psychosocial approach to the treatment of psychotic patients. Some hospitals affiliated with universities, such as the Salpetrière in Paris, and the Burghölzli in Zurich, came to promote psychological models.

The psychiatric paradigms of late nineteenth century are best reflected in the work of the German psychiatrist Emil Kraepelin (1919). In his own time, Kraepelin was the world’s most prestigious theorist about mental illness. In recent decades, his ideas have again become influential, leading to the formation of a “neo-Kraepelinian” school (Klerman 1986). Although Kraepelin has been criticized for a supposed lack of humanism, he stood for principles that have remained at the core of his discipline: a focus on the phenomenology of mental illness, a hardheaded empiricism, a refusal to make unnecessary speculations, and a resistance to invoking constructs that cannot be operationalized and measured.

At the turn of the twentieth century, mainstream psychiatry continued to be based on the observation of psychotic patients. This approach was unsatisfactory to a younger generation who wanted to work in innovative and creative ways with a broader population. In this context, the new discipline of psychoanalysis was in a position to attract many clinicians, both medical and nonmedical.

Most practicing analysts did not work in hospitals but treated “neurotic” outpatients in offices and clinics. Psychoanalytic theory not only offered a new way to understand psychopathology but also was a general theory of human psychology (Gellner 1993). The method generated enthusiasm for its therapeutic potential. Psychodynamic ideas also had great impact outside formal analysis on the practice of psychotherapy and on the culture as a whole (Hale 1995).

The institutional structure of psychoanalysis was a factor in the spread of its influence. Freud’s decision to create separate pedagogical institutions to promote his ideas encouraged practitioners to make their primary allegiance psychoanalysis rather than psychiatry or medicine. In fact, some of the early analysts were non-M.D. psychologists or teachers.

Between the First and Second World Wars, biological and psychological models contended for the soul of psychiatry. The biological camp could not yet offer adequate treatments for the major psychoses, even though they devised a number of experimental therapies. The only Nobel Prizes in medicine ever awarded to physicians working with psychiatric patients were given to nonpsychiatrists: the Austrian neurologist Wagner-Jauregg, for the malarial treatment of syphilis, and the Portuguese neurosurgeon Moniz, for psychosurgery. (A more recent Nobel Prize awarded to American psychiatrist Eric Kandel was for research on memory.)

After the Second World War, psychiatry was divided into two camps: those who conformed to a medical model and provided organic treatments and psychoanalysts committed to the “talking cure.” On the biological side of the divide, electroconvulsive therapy (ECT) was being overused. In the absence of effective medications, ECT—which eventually found its place as an effective treatment for melancholia—was prescribed for all forms of depression (Shorter 1997). Insulin therapy was also a popular method, although it was later discarded when clinical trials failed to demonstrate its effectiveness. Psychosurgery was another psychiatric “fad” that was later almost entirely discredited (Valenstein 1988). Effective biological treatment only became a reality in the 1950s, with the development of antipsychotics and tricyclic antidepressants.

On the psychological side of the divide, psychoanalysis reached the zenith of its influence in the 1950s and 1960s. For a time, training in analysis was almost a “must” qualification to become a chairman of an academic department of psychiatry (Eisenberg 1995). These clinicians were strong on charisma and rhetoric but largely ignorant of research methods. Yet even at its time of greatest dominance, psychoanalysis was itself divided. The movement has always had a tendency to splinter, and many variants of Freud’s original model existed. Among the forms of psychotherapy common in the 1960s were “neo-Freudian” variants of psychoanalysis, client-centered therapy, group therapy, behavior therapy, and family therapy. Still, most of these offshoots remained far closer intellectually to psychology than to medicine. As different as these ideas were, most had one important thing in common: they were rooted in theories attributing psychopathology primarily to childhood adversities (Paris 2019).

Today, the profile of theory and practice in psychiatry has greatly changed. As in the previous century, many if not most psychiatrists adhere to biological theories. The fact that we now have pharmacological agents that are effective and have relatively few side effects has had a profound effect on the way clinicians think. When so many disorders are correctable with medication, clinicians are much more tempted to espouse theories reducing psychopathology to “chemical imbalances.” The fact that no such imbalances have ever been observed does not seem to discourage those who adopt this ideology.

Today, the psychotherapies have a narrower scope in psychiatry than they once did. One reason for this decline is that psychotherapy was oversold, leading to disappointment and disillusionment (Eisenberg 1986). Although psychotherapeutic methods have been shown by empirical research to be effective for a wide variety of patients (Lambert 2013), they often work more slowly than medications and are much less effective for patients with severe psychopathology. Another issue is that traditional methods of psychotherapy are lengthy, making them expensive and inaccessible. This problem has been at least partially addressed by a move to time-limited brief therapy, which has a strong evidence base.

In contrast, medications for common mental disorders are relatively inexpensive, and prescribing them uses less clinician time. The problem is that only half of all depressed patients have a good response to antidepressants, which have only a narrow advantage over placebo (Kirsch et al. 2008). The idea that antidepressant failure (often called “treatment-resistant depression”) can be managed by adding more medications to a “cocktail” may work for a minority of patients, but for most has only slim support from research (see Paris 2010 and Moncrieff 2018 for detailed reviews).

The impact of these ideas has been profound, however. More patients are on psychiatric medication—now about 12% of the U.S. population (Mojtabai 2008; Pratt et al. 2017) than at any other time in history. Another set of effect derives from tendencies to continue prescriptions indefinitely and to put patients on polypharmacy regimes when they do not work, leading to cascades of side effects that are more predictable than good clinical outcomes. As a consultant to family practitioners and to other psychiatrists, I find these problems ubiquitous. Clinicians who believe that depressed patients have chemical imbalances that have little to do with their life circumstances apply this ideology by aggressive prescribing practices. Referrals to psychotherapy may not be made at all or are only considered when depression appears to be stubbornly “treatment resistant.” In addition, much continuing medical education is paid for by pharmaceutical companies, and their representatives are frequent visitors to physicians in office practice. “Big Pharma” does not promote medications that have been in use for years (and whose side effects are well known); instead, they promote new medications that tend to be “copycats,” with their own side effects, and are much more expensive for consumers.

Meanwhile, psychotherapy remains difficult to access for many patients. It may be insured by managed care plans, but the number of sessions covered is usually lower than what research shows is likely to be effective (Lambert 2013). Moreover, many patients remain uninsured. Thus, the structure of the U.S. mental health system (assuming it deserves to be called a “system”) stands in the way of making rational choices between applying a purely biological model or a biopsychosocial approach. Finally, residency training in psychiatry does not always provide adequate preparation for conducting evidence-based psychotherapy. Although few mourn the disappearance of psychoanalytic dominance, programs vary greatly in whether they have teachers who can transmit current knowledge about effective psychosocial treatments.

In theory, combined treatment with medication and psychotherapy remains the most frequently used option for management of common mental disorders, such as depression (Olfson and Marcus 2010), but we do not know the quality of psychological treatment that most patients receive or whether it corresponds to evidence-based standards. Psychiatric models have had an unfortunate history of going from one extreme to another. Decades ago, Grinker (1964) critiqued the unbridled enthusiasm for community psychiatry that characterized his time in a memorable phrase: “psychiatry rushes off in all directions.” More than 50 years later, we are still searching for the right direction.

Biological psychiatrists have been insufficiently interested in studying the psychological precipitants of mental disorders. In a witty comment, Lipowski (1989) suggested that whereas the dominance of psychodynamic psychiatry was characterized by “brainlessness,” the contemporary biological era is characterized by “mindlessness.” There is a real danger that contemporary psychiatrists will lose interest in the person. This would be a tragic outcome of the great achievements of modern biological research. No matter how sophisticated we become in studying the brain, when we stop talking to patients, we lose the soul of our profession. Moreover, we cannot fully understand the origins of mental disorders through their biological correlates. As wise physicians have always known, all illnesses have a unique course, shaped by the events of patients’ lives.

At the same time, few psychotherapists have taken the implications of genetic research into account in their work. Most clinicians accept that certain illnesses, particularly schizophrenia and bipolar mood disorder, have a strong genetic component. These cases are rarely referred for psychotherapy, although some evidence has shown that support can make a difference. Unfortunately, some therapists still believe that other forms of mental disorder are largely psychological.

As shown in this book, genetic factors are involved in the development of almost all forms of pathology, even conditions such as PTSD and personality disorders that have often been considered primarily environmental in origin. Unfortunately, much of the psychotherapy community continues to subscribe to an environmentally reductionistic paradigm, explaining psychic distress as a direct reaction to life events. These clinicians are ignoring the genetic and biological factors underlying even the most common psychological symptoms. The ebb and flow of scientific ideas is not, of course, determined only by fashion. In the long run, theories must stand or fall on the weight of cumulative empirical evidence. Nevertheless, in the short run, there is some relationship between theoretical preferences and cultural values.

Environmental reductionism had its most powerful impact in North America. This may not be a coincidence. Frank and Frank (1991) suggested sociological reasons for the difference between American and European ideas, pointing out that American society deeply values individualism, promoting the belief that individual goals should not be shackled—neither by tradition nor by biological imperatives. The idea that anybody who wants to make something of his or her life can do so with enough persistence is a deeply held value in the culture, often tagged with the phrase “only in America.” However, psychiatry in the United States went on to make a 180° turn, prioritizing biology over psychology.

A disparate range of environmentalist theories have been influential in America, including some schools of psychoanalysis, cognitive-behavioral theories, and social models of mental illness. Starting in the 1990s, theories accounting for adult symptoms on the basis of childhood trauma had a large impact on clinicians, as well as on the general public. What all these environmental models have in common is that they attribute the etiology of mental disorders almost entirely to psychological and social factors: traumatic life events, bad families, or a sick society. These ideas are seductive because, however misleading, they contain a grain of truth. There is empirical evidence that traumatic life events increase the risk for many forms of psychopathology, that dysfunctional families are more likely to raise children with mental disorders, and that levels of social cohesion affect the prevalence of psychiatric illness (see Chapter 4).

Yet what narrowly environmental models fail to take into account is that associations between risk factors and psychopathology are only statistical correlations that do not prove causality. Moreover, although more people who are exposed to risks will fall ill, most will not. This is because the effects of the environment depend on factors within the person. That interaction is the main theme of this book.

The nature-nurture debate has also raised sharp controversies in the social sciences. Traditionally, psychology, sociology, and anthropology have all emphasized environmental influences on individual differences. Steven Pinker (2002) described a “standard social science model” as a version of seventeenth-century philosopher John Locke’s concept that children are a “blank slate” on which the environment writes a script.

The resistance of the social sciences to integrating biology has been fierce and often bitter. Sociobiology, as described by E.O. Wilson (1975), is a theory that explains universal human behavioral patterns in terms of natural selection, but Wilson was attacked by Marxist biologists for these ideas (Segerstråle 2000). Although Wilson is a noted Harvard entomologist and a lifelong liberal Democrat, he had to endure a physical attack at a conference when an opponent poured ice water on him. When he came to speak in my own city of Montreal in the 1970s, a sociology professor, who probably had not read anything Wilson had written, asked me if I wanted to help a protest against the lecture. (Yes, even then, speakers could be shouted down by “activists.”)

Evolutionary psychology is a closely related discipline (Buss 2019). It has endured similar attacks, probably because it challenged a postwar consensus that environment explains everything, resisting any application of evolution and genetics to the social sciences.

What was all this drama about? It comes down to politics. If you believe in Marxism or other Utopian ideas, then you must believe that there is nothing to the concept of human nature and that humans are a blank slate. It follows that a just society can be built through hard work and idealism. If, on the other hand, you are conservative, you are likely to believe that there are limits to the reform of society, based on a delicate balance between selfishness and cooperation. The libertarian social commentator Thomas Sowell (2010) described these points of views as “unconstrained” vs. “constrained” visions of the human condition. Pinker (2002) reformulated these points of view as a “utopian vision” vs. a “tragic vision.” Later, Pinker (2018) welcomed the progress that has been made in the quality of human life since the Enlightenment, but does not believe in perfection. These views continue to meet resistance from leftist thinkers.

Although I support a tragic vision of human nature, that does not mean treating patients is not useful or important. What it does mean is that one should not have utopian goals, either by correcting errors in human biology or by teaching people how to live better.

Another domain in the social sciences in which nature and nurture clash is the scientific study of human intelligence. The evidence is clear that IQ is heritable at the same level as other traits (Plomin 2018). Yet some have believed that these findings are artificial and even have racist implications (Lewontin et al. 1984). Scarr (1991) discussed why the genetic factors in intelligence and personality are resisted or dismissed by so many people and asked, “Why the resistance to the idea that parents transmit genes to their children, with the consequence that their children resemble them to a modest extent? Because behavioral scientists understand genetic transmission to mean that nothing can be done to change the unfortunate lot of people who inherit bad genes” (p. 385). The contrary is true. As opportunities become more equal, individual differences tend to stand out more dramatically. As Scarr (1991) went on to point out, “egalitarian provisions raise the heritability of personal and intellectual characteristics in Western populations” (p. 386). That is why intelligence is less heritable in African Americans, where poverty interferes with education (Plomin 2018).

Although the genetic lottery may not be fair, an understanding of how it affects individuals can help us take a more humane view of mental illness. When we recognize that patients have inherent areas of vulnerability, we need hold neither them nor those in their immediate environment entirely responsible for their problems. When we treat patients, we can provide them with whatever forms of treatment have been shown to be effective, without being judgmental. Thus, acknowledging the genetic factors in mental disorders need not lead to determinism or despair. Instead, it can be the basis of a higher form of humanism.

The triumph of modern medicine means that we usually recover from periods of acute illness and live much longer. As a result, the focus of medical research and care has shifted to chronic diseases. This makes it much closer to psychiatry. Historically, medical genetics concerned relatively rare conditions with classical Mendelian inheritance. However, chronic illnesses, like mental disorders, arise from complex genetic patterns and multiple risks from the environment.

A large body of evidence supports the principle that the genetic susceptibility to common chronic illnesses such as coronary artery disease, essential hypertension, or diabetes mellitus involves polygenic mechanisms of inheritance, amplified by environmental risks (Kendler 1995). As each genetic factor interacts with other genes, overall liability can cross a threshold and determine whether overt disease develops, as well as the severity of illness. One example is the “two-hit model” of carcinogenesis, in which pathology depends both on biology (the mutation of genes that stimulate cell proliferation and the deactivation of tumor suppression genes) and environmental mechanisms (Knudson 1996). For example, people with a heritable predisposition to lung cancer are much more likely to develop the disease if they also smoke. The same idea has been applied by to schizophrenia (Maynard et al. 2001). The theory is that a heritable (and/or intrauterine) risk factor disrupts brain development but only causes disease when a second hit occurs in adolescence or young adulthood.

Genetic susceptibility is a necessary condition for the development of most chronic medical illnesses and can determine which type of illness an individual can develop. It is not, however, a sufficient condition for most diseases, which will only become clinically apparent when environmental factors increase liability. These theories may also explain why the same illness in different individuals can have a different onset and course. When genetic factors are stronger, illness often tends to develop at an earlier age. When diseases have an early onset, there has not been sufficient time for environmental risks to accumulate and provoke the onset. They are therefore more likely to be associated with a stronger genetic loading (Childs and Scriver 1986). Conversely, a disease that develops later in life is more likely to be influenced by relatively weaker genetic factors but by stronger environmental factors: the older the person is, the longer the time available for environment stressors to exert their cumulative effects. Behavioral genetics shows that death occurring before the age of 60 years depends strongly on inheritance, whereas death after age 60 is more strongly related to environmental factors (Sørensen et al. 1988).

As a researcher in cardiac disease once summarized the model: “Most major chronic diseases probably result from the accumulation of environmental factors over time in genetically susceptible persons” (Williams 1988, p. 770). Natural selection leads organisms to evolve mechanisms of resilience against disease so that only the cumulative effects of multiple environmental insults will overwhelm these defenses. These models of disease apply well to mental disorders. In psychiatry, the nature-nurture debate can only be resolved through recognition of interaction between genes, the cumulative effects of environmental adversity and the effects of risk factors on vulnerable individuals. This principle needs to be confirmed through careful examination of empirical evidence. The rest of this book is devoted to that task.