Are authoritative diagnoses of mental and psychological illnesses reliable? | World Mental Health Day Special

Today is the 31st World Mental Health Day. Nowadays, knowledge about mental health has been widely disseminated, and more and more people are actively going to psychiatric departments and consultation rooms to seek help. However, the diagnosis of mental illness is currently based on symptoms, and it is impossible to name and identify the disease based on the cause or pathology. In this case, is the diagnosis really "accurate"? How targeted and effective is the psychotherapy based on the diagnosis?

Written by Ruohan (Master of Clinical Psychology and Cognitive Neuroscience, University of Munich, Germany, PhD student in Clinical Psychology)

Today, people have a better understanding of mental illness or psychological illness, but there are still many misunderstandings and confusions in society, as well as various implicit prejudices, avoidance and even discrimination. In fact, the fast pace and strong competition of modern social life will bring huge psychological pressure, and the various contradictions and conflicts between personal desires to realize the value of self-existence and the restrictions of family and interpersonal environment in the context of social change will also bring many psychological burdens and harms, which make modern people's mental/psychological problems more and more prominent. Those who carry all kinds of secret but extremely heavy inner pain, on the one hand, have to face their true feelings, and on the other hand, the misunderstanding and prejudice of the outside world will once again deepen the pain they have to endure.

In fact, mental/psychological illness is as "normal" as physical illness. They do not come out of thin air, but have profound physiological basis, life experience basis and real inducement. It is the responsibility and mission of researchers and doctors to explore and understand the truth behind mental/psychological illness and "prescribe the right medicine" to help patients to the greatest extent. Although so far, limited by objective research methods and the level of human knowledge development, our understanding of pathological mechanisms is still quite limited - in the study of all these mechanisms such as the operation of the brain, the interaction between the body and mind (physiological-psychological) of human beings as an organic whole, and the interaction between human beings and the social and interpersonal environment, there are still a lot of blank areas waiting for us to explore in depth, which is also the driving force for researchers in related disciplines to keep moving forward.

Diagnosis, important but "subjective"

Similar to the process of seeing a doctor on a daily basis, when providing help to patients/visitors in clinical practice, the first step faced by both doctors and patients is to know what is happening and make a diagnosis.

We often see that visitors are eager to know what is happening to them, or they have searched for their symptoms on the Internet. They need to hear the name of a disease. The sense of certainty brought by this name can make them feel a little relieved, because it also means that they have found a possible direction to deal with the dilemma. The same is true for doctors. Professional requirements and psychological needs drive them to make a "diagnosis."

From an objective point of view, diagnosis is the basis of symptomatic treatment, and its core importance is self-evident.

However, unlike simple physical diseases, the diagnostic criteria and process of mental illness and psychological illness are much more subjective. Whether it is the questionnaire scoring that is common in China, simple outpatient questions and answers, or the more rigorous, standardized detailed interviews followed by quantitative coding and scoring, subjective reports are used as the main basis for diagnosis - of course, this is also determined by the nature of mental/psychological diseases themselves: the client's expression of his or her subjective experience is very important. And these subjective experiences are usually very individual, and the symptoms vary from person to person and are complex. Doctors need to unravel the various appearances and make identifications and judgments. Therefore, the doctor's own subjective understanding of mental/psychological diseases and the degree of understanding play an extremely important role in the qualitative and quantitative judgment of the disease and the choice of subsequent treatment methods.

So, as so-called "professionals" or representatives of "authority", to what extent can we give patients/visitors an "accurate" answer and provide "accurate" help and services based on it? To what extent can the disease classification and diagnosis standards used by doctors "accurately" reflect the truth about the disease?

Two authoritative classification and diagnosis systems

There are currently two internationally used classification and diagnosis systems for mental/psychological illnesses:

1) Chapter 6 of the World Health Organization (WHO) ICD-11 (International Classification of Diseases, 11th revision, 2018) [1] , entitled "Mental, behavioural or neurodevelopmental disorders". In the previous version of ICD-10 [2], which was first published in 1989 and used for nearly three decades , this chapter was called "Mental and behavioural disorders";

2) The American Psychiatric Association (APA)’s DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition, 2013) [3] . The first two editions were the fourth edition of DSM-IV published in 1994 and the fourth edition of DSM-IV-TR published in 2000 [4, 5].

Figure 1. ICD-11 and DSM-5

Both classification and diagnosis systems have a certain history. The first edition of DSM was published in 1952, while the earliest prototype of ICD can be traced back to 1891 because it involves all disease categories. Both are generally revised every ten years on average.

Every revision and development of the classification and diagnostic system of mental/psychological diseases is, on the one hand, based on a new understanding of the disease and a deeper understanding of the principle brought about by a large amount of clinical scientific research, which leads to the modification, adjustment, refinement and supplementation of the classification methods and diagnostic principles; on the other hand, it is also influenced by the broader social, political, historical and cultural development background [6, 7].

Comparing the two classification systems horizontally, the biggest commonality between the two is that they both mainly use external symptoms as the main basis for disease classification and diagnosis, rather than the cause of the disease. Therefore, the "diagnosis conclusion and classification" may not truly reflect the "essence" of the disease.

Comparing the two classification systems vertically, they are both "advancing with the times". This also means that the "diagnostic conclusions and classifications" at this moment are only the current cognition in the historical process, not the final conclusion .

Therefore, they are not perfect. In fact, researchers have identified many shortcomings of current diagnostic systems [7, 10, 11]. Let’s look at some of the problems they have revealed.

Confused classification ideas

Let’s take the classification diagnosis of personality disorders as an example:

In the previous DSM-IV and DSM-IV-TR, 11 specific personality disorder categories were divided into three major groups, and the diagnostic criteria for each category were a combination of symptoms:

A. Weird and eccentric group (including: paranoid, schizoid, schizotypal personality disorder)

B. Dramatic/emotional/impulsive group (including antisocial, borderline, histrionic, and narcissistic personality disorders)

C. Anxious/fearful group (including avoidant, dependent, and obsessive-compulsive personality disorders)

D. Other unspecified

The latest version of DSM-5 has made new attempts to diagnose personality disorders, but it has not completely abandoned the use of categories as diagnosis. In the new attempt, the diagnostic criteria are no longer simply listing symptoms, but provide specific descriptions of 6 specific personality disorder types and corresponding personality functions and personality traits; and allow any other personality disorders that do not meet these 6 criteria to be described specifically using the two dimensions of "personality functions" and "personality traits". Similar changes have also occurred in ICD-11.

Antisocial personality disorder

Avoidant personality disorder

Borderline Personality Disorder

Narcissistic Personality Disorder

Obsessive-compulsive personality disorder

Schizotypal personality disorder

Other specific personality disorders

Many of you will have heard of some of them.

From the classification and naming of personality disorders mentioned above, you may have discovered that in addition to the types with specific names, there are also items that cannot be clearly classified. This situation occurs in almost all diagnostic categories, that is, the symptoms actually observed may not meet the diagnostic criteria of any given disease type. In actual clinical applications, it is inevitable that " comorbidity " occurs frequently, that is, the patient's symptoms meet the diagnostic criteria of two or more disease types at the same time.

As clinical observations continue to accumulate, some diagnostic categories list increasingly longer supplementary categories, special case descriptions, additional features, or similar "comorbidity" items with typical symptoms of other diagnostic categories to adapt to clinical use. Here are a few simple examples.

For example, in ICD-11, the diagnostic classification code 6A70 "mono-episode depression" includes:

6A70.0 Single episode of depression - mild;

6A70.1 Single episode of depression - moderate - without psychotic symptoms;

6A70.2 Single episode of depression - moderate - with psychotic symptoms;

6A70.3 Single episode of depression - severe - without psychotic symptoms;

6A70.4 Single episode of depression - severe - with psychotic symptoms;

6A70.5 Single episode of depression - unspecified severity;

6A70.6 Single episode of depression - currently in partial remission;

6A70.7 Single episode of depression - currently in complete remission;

6A70.Y Other specified single-episode depressive disorder;

and 6A70.Z Single episode of depression - unspecified/unspecified

Feeling dizzy and tired? But this is still only a small part of the diagnostic categories related to depression.

The DSM-5 uses ten "additional explanation items" to allow clinical users to add symptoms and features outside the main diagnostic criteria to a main diagnostic category in the form of supplementary explanations when they observe them. For example, the symptoms and features of "panic attack" and "catatonia" are added to many diagnostic categories. For another example, the characteristics of "anxiety disorder" are added to the diagnosis of "bipolar disorder" and "major depressive disorder"; and the mixed symptoms and features of "mania and depression" are added to the diagnosis of "bipolar disorder" and "major depressive disorder".

This operation method makes it easier for clinical users to make classifications during diagnosis, but it also reflects the confusion of the classification concept itself to a considerable extent .

A more intuitive example is that DSM-5 also splits the original general category of "affective disorders" (in DSM-IV and DSM-IV-TR, affective disorders mainly include bipolar disorder and depression) into "bipolar and related disorders" and "depression", and lists the two as three general categories at the same level as "schizophrenia spectrum and other psychotic disorders", and regards bipolar disorder as a connection and transition between psychotic disorders and depression; but at the same time, it wants to use "schizoaffective disorder" under "schizophrenia spectrum and other psychotic disorders" to bridge the symptoms of schizophrenia and affective disorders (bipolar disorder and depression).

Are you dizzy?

Figure 2. These two intertwined and unclear classification concepts coexist in DSM-5 (author’s illustration)

The more important question is: What is the point of these long and complicated classifications that do not reflect the essence of the disease? Can they really accurately guide us to treat (or even cure) the patient's/visitor's disease?

Difficult to unify diagnostic criteria

Not only is the classification of disease categories itself questionable, but there are also major problems with the formulation of specific diagnostic criteria. In July 2019, the journal Psychiatric Research published a quality analysis study on DSM-5[7], which found that the diagnostic criteria of several important diseases (Note 1) themselves have heterogeneity problems, that is, the diagnostic criteria are very inconsistent. Different types of diseases have very different reference standards for diagnosis, requirements for symptom duration, severity, and judgment angles. Some diseases have highly specific diagnostic criteria, while others have more flexible requirements for symptom manifestations. The consequences are surprising - for example, there are a total of 24,000 possible symptom combinations that meet the DSM-5 diagnostic criteria for panic disorder, but only one symptom combination meets social phobia.

Note 1: Includes schizophrenia spectrum and other psychotic disorders, bipolar (i.e., depression and mania) and related disorders, depression, anxiety disorders, trauma and stress-related disorders

This heterogeneity is also reflected in the diagnosis of different individuals. Two people with completely different symptoms can receive the same diagnosis - studies show that this is the case for 64% and 58.3% of the disease diagnoses in DSM-IV-TR and DSM-5, respectively. For example, the possibility of symptom combinations for post-traumatic stress disorder (PTSD) itself exceeds 600,000, an astonishing number that means that the diagnosis of PTSD is very confusing. And because PTSD often co-occurs with other disorders, such as depression, there are 2.7 billion (!!!) different combinations of symptoms in the DSM-5 diagnostic criteria that may meet the diagnostic criteria for both PTSD and depression; if the other four common co-morbidities are also counted, the possibility of symptom combinations will exceed the number of stars in the Milky Way. Although the possibility of 6 diseases co-occurring at the same time is relatively small, these calculations intuitively show how huge the differences in the symptoms of the same category of diseases can be, and countless different symptom combinations, even completely different symptoms, can be diagnosed as the same category of diseases.

At the same time, confusion and duplication of classification standards inevitably lead to some symptoms appearing simultaneously in the diagnostic standards of different disease types. For example, "depressive episode" appears simultaneously in major depression, bipolar and related disorders, and schizoaffective disorder; "hallucination" appears simultaneously in schizophrenia and other psychotic disorders, depression with psychotic features, bipolar and related disorders, and PTSD.

So, in the end, we see that: on the one hand, different, even completely different combinations of symptoms can be diagnosed as the same type of disease; on the other hand, different disease categories are allowed to have the same symptoms; what's worse, the symptoms listed in the diagnostic criteria cannot fully cover all the symptoms actually observed, resulting in the "real" disease not always fully matching the diagnostic criteria of a specific category.

“Too Primitive” Category Diagnosis

If symptoms themselves can be used as an absolute criterion for diagnosing disease, then what do the above phenomena mean?

This is a question that the existing diagnostic system for mental and psychological diseases cannot answer, and it also reveals their inevitable dilemma - the types of artificial demarcations that can be listed are limited, while the actual symptoms vary greatly. It is true that "categories" make it easy for clinical users to draw a conclusion - to classify patients into one or several disease categories, but their significance in understanding the nature of the disease is very limited, and may even hinder it.

Because the classification pattern of disease categories also seems to be a suggestion (to the public, even to general users) that we have understood the nature of each type of disease and classify and group them according to the nature of the disease.

But this is not the case. For example, the presence of "neurodevelopmental disorders" in both classification systems seems to suggest to the public that only this type of disease appears in the neurodevelopmental stage and is the result of abnormal development of the nervous system (as a cause), but the description of the diagnostic manual also acknowledges that other diseases may also appear in this stage. For example, "schizophrenia and other psychotic disorders" seems to imply that only this type of disease is "psychotic", but in fact, in other diagnostic categories such as "depression" and "bipolar disorder", there are also diagnostic items with psychotic symptoms.

In fact, the current classification and diagnosis system has been declared "non-theoretical" from the beginning, that is, the classification principle is not based on a theoretical model to explain the disease. But at the same time, the latest versions of ICD and DSM have classified "diseases related to stress and trauma" as a separate category, which is another clear classification method based on etiology. The naming of this category "stress-related disorders" (ICD-11) or "trauma and stress-related disorders" (DSM-5) also implies that other categories of diseases seem to have nothing to do with "stress and trauma."

However, existing experimental studies are sufficient to show that many current categories of diseases are related to high stress and trauma, such as depression, bipolar disorder, anxiety, obsessive-compulsive disorder, eating disorders, schizophrenia and psychotic disorders, dissociative disorders, and functional neurological disorders (medically unexplained symptoms). Moreover, these traumas or stresses often occur in childhood. A person's early individual experience (including interpersonal experience) since childhood, especially experience related to stress and trauma, is critical to understanding a person's mental health status in adulthood, and understanding a person's susceptibility to mental and psychological illnesses and symptom development. For example, auditory hallucinations in schizophrenia are highly correlated with childhood sexual assault; and paranoia is mostly related to childhood neglect. However, the current diagnostic system only understands these symptoms as "abnormal" or "disordered", and basically does not put them into the context of a person's overall life history to understand the causes and mechanisms of their formation.

In fact, all observable symptoms and their interrelationships, including various comorbidities, can convey information and hints about pathological mechanisms—the deeper "bio-psycho-social" mechanisms behind them. However, the current dominant classification and diagnosis system hardly involves these contents. Simply put, the characteristics of the current classification and diagnosis system can be summarized as follows: classification is based on phenomena first, pathological mechanisms are not the main consideration, and it is almost not based on theory, and it is not an explanatory model of the disease.

In general, it can be seen that this diagnostic method that hopes to use symptoms as a basis to divide independent disease categories objectively has considerable defects and limitations. This brings many problems to both clinical application and scientific research. These "category" diagnostic methods that may be seriously deviated from pathological facts may not only mislead patients, but also be a false suggestion to clinical practitioners, causing cognitive preconceptions and solidification, which may cause them to miss the precious first-hand observation, understanding and reflection opportunities in clinical practice. From the perspective of scientific research, this "separate category" can be said to be "meaningless" [7]. It is precisely because its classification basis is superficial and has no real theoretical basis that it lacks the unified internal logic and rigor of setting standards. For example, as early as 1968, scientists pointed out that the concept of "schizophrenia" is "a semantic Titanic that is doomed to fail before it sets sail" and "a concept that is so ambiguous that it is almost unusable in scientific research", mainly because "separate categories are too primitive in logic for scientific research" [12].

In the past, when scientists' understanding of diseases was still very rudimentary, this classification and diagnosis method based mainly on intuitive symptoms certainly had its rationality. As mentioned earlier, as part of social and cultural development, the development and revision of the disease diagnosis system has corresponding social, political, historical and cultural roots. However, different stages of social development bring different influences and limitations, making the development of the diagnosis system fragmented and fragmentary, which also caused the heterogeneity of diagnostic standards and confusion of classification concepts in the diagnosis system.

As more and more clinical and experimental evidence emerges and as our understanding of pathological mechanisms continues to deepen, the entire diagnostic system may need to be comprehensively reorganized and updated. In this regard, "a disease assessment method that can recognize and understand individual experience may be more effective in understanding the disease than adhering to an insincere category system" [7].

How to understand mental/psychological illness more appropriately?

Although scientists do not fully understand how mental/psychological phenomena work, based on what we do know, we can generally assume that:

The brain, as the most direct biological basis of all mental/psychological phenomena, first follows a deeper and more microscopic biological (biochemical and biophysical) operating mechanism; secondly, from a relatively macroscopic level, it is a super complex and sophisticated network system, including various complex structures and functional areas, which are relatively independent and have high-density connections in terms of structure and function, forming an extremely complex functional network in the brain. The realization of each psychological function and psychological process is usually the result of the coordinated participation of different structures and functional areas; the higher and more complex the psychological function and psychological process, the more structures and functional areas need to participate.

All observable or unobservable, conscious or unconscious, volitionally or involuntarily controlled mental/psychological phenomena are the integrated results of different structures and functional areas in this large network being activated in different proportions. Accordingly, any one or several nodes in this network and the associated regions or functional networks, due to any internal or external reasons, any breadth and degree of problems, will trigger the expression of different combinations of symptoms. It is conceivable that the possibilities of such symptom combinations are endless.

In addition, stress and trauma are key pathological factors in the generation and development of mental and psychological diseases. Whether it is the great stress and trauma events that occur in reality or in childhood, they may affect the brain, even causing irreversible damage. The earlier this impact occurs, the more profound and difficult it is to reverse. As scientists continue to deepen their understanding of the workings of the brain, such as how people's experiences affect the brain; how disorders of the stress or trauma processing system and other related systems in the brain are related to different clinical symptoms;... We will increasingly understand the deep causes of each symptom and the internal connections between different symptoms, and understand the psychological logic and corresponding physiological basis for the generation and development of each symptom, that is, their true pathological mechanism.

The special thing about psychology, neuroscience, psychiatry and other related disciplines is that they study the operation of the human mind through the human mind. Pure literature and art only need to focus on expressing the content of the subjective spiritual world of human beings, pure science and engineering fields only explore and apply the objective material world, and pure biology only explores the physiological basis of life. Psychology and related sciences explore the spiritual world above the material basis of life - the world that transitions from the material basis to the spiritual content - which may not be easier than exploring the universe.

There are still many questions that have no (accurate) answers. Everything is still under exploration. In addition to understanding the disease, there is also the optimization and development of treatment methods. If you need and expect them, please also understand their current objective shortcomings; if you have doubts about them, please be patient with them. With the rapid advancement of research technology, the continuous development and improvement of these fields in the future can be expected.

How do you think psychotherapy/counseling would be more beneficial?

Enough clinical and experimental studies have shown that "relationship" itself plays a very core role in the formation and treatment of mental illness, especially those mental disorders that are closely related to stress and traumatic events in an individual's interpersonal life.

Human behavior and experience are controlled by the brain, and experience itself is constantly reshaping the brain. Human experience is essentially the experience of relationships. In the experience and experience of relationships, the brain can undergo adaptive self-regulation and change. Humans are social beings. Interpersonal relationships are another key risk factor for the formation of mental illness, and also a key protective factor for treatment. The quality of the doctor-patient/consultant relationship is one of the most important factors for the effectiveness of psychotherapy, transcending all schools and methods of psychotherapy. Therefore, it will be very beneficial for patients to form a stable, trusting, and cooperative treatment/consultant alliance between doctors, patients, and consultants.

Just as natural ecosystems have a certain self-purification ability, when the degree of pollution exceeds the system's self-regulation ability, it will cause irreversible damage to the system. At this time, external forces are needed to remove the pollution in order to help the system slowly restore its normal state and regulatory function. The same is true for our brain. Stress or trauma is like a pollutant that destroys the healthy balance of the brain's physiological internal environment. If it is in chronic high pressure for a long time, the brain's stress response system may lose its normal self-regulation ability and undergo pathological changes and damage. Therefore, it is very necessary to relieve stress in a timely manner. Once the pressure exceeds the level that we can adjust and bear, we should seek help from others in time.

Psychological problems often develop over time; accordingly, psychotherapy or psychological counseling usually does not take effect too quickly - this is in line with the objective law of expectation. With the gradual establishment of a working alliance between the doctor and the patient, the counselor and the visitor, the patient/visitor can face himself and express himself honestly, which will play a very important role in understanding his own spiritual dilemma and treating the disease.

Although doctors and counselors have knowledge tools, they are not wizards holding crystal balls who can see directly into other people's minds and change other people's experiences. Their entire understanding of patients/visitors comes mainly from the interaction between the two parties. It is impossible for them to directly (or even force) change the thoughts and feelings of patients/visitors, but they must gradually induce the other party to make active adjustments and changes through real interaction between the two parties. At the same time, patients/visitors are actually helping doctors/counselors to understand the nature of the disease from various symptoms through different cases and with a broader observation perspective, in order to better help more people in the future. Every bit of clinical accumulation is very precious, and obtaining these most direct first-hand observation and research materials is inseparable from the contribution of patients/visitors.

On the other hand, it is more important for doctors, therapists or counselors to continuously improve their professional knowledge and abilities and strengthen their ethical self-discipline, especially in the domestic environment where the field of psychotherapy is still in its early stages. The self-requirements of doctors are particularly valuable and important. Given that all the disease explanation models, diagnostic tools and treatment methods currently used are far from perfect, it is also very necessary to jump out of the habitual thinking framework and examine the knowledge "tools" used from a broader perspective.

Although doctors are not omnipotent, they should and must be the ones who constantly explore how to understand and assist patients/visitors to alleviate pain and get out of difficulties.

Finally, good treatment and consultation results always depend on the joint efforts of both parties, and also require considerable persistence and patience.

No small matter of the mind

Mental/psychological illness is as "normal" as physical illness and is just as important. Fundamentally, the diagnosis and treatment system for mental illness and the medical security system for mental health should be standardized and improved as much as possible, so that both doctors and patients can enter professional treatment without worries and focus on solving problems with peace of mind and full concentration. These are being gradually tried and promoted.

Of course, prevention is the most important thing. Professionally and effectively publicize relevant scientific knowledge, especially popularize and guide parents in the process of children's growth, establish a sufficient social support system (including for families and relatives), so that individuals can grow up in a family and interpersonal environment that is as healthy and nurturing as possible; make individual susceptible personality traits "stronger" earlier through consultations aimed at "personal growth"; make stress or trauma be timely channeled and reconciled, so that they will not develop further; make many harmful intergenerational transmission of bad patterns be intervened and blocked... There is nothing trivial about the mind, and there are many things that can be done.

Just as our country has made great progress in many areas, we actually have the resources and capabilities (including social culture, ways of thinking, and even institutional advantages) to establish a complete service guarantee system that conforms to our own cultural atmosphere and the psychological needs of the public, and provide the people with better mental health services.

At the same time, my country has a large population base and is in a stage of sustained social development and transformation, so there are abundant cases available. Under the premise of professionalism, standardization and rigor, clinical practice and scientific research have huge resource advantages. By cherishing and making good use of these resources, we may make great contributions to our understanding of the entire mental/psychological disease model, and to the expansion and improvement of diagnostic systems and treatment methods.

Whether you are a doctor, researcher, patient in need of help, or someone who is not related to this field, after reading this article, you may feel disappointed in this field, but I hope you can see hope from it. At least, not blindly believing in it or arbitrarily denying it, and objectively and rationally looking at and understanding the current development status of related disciplines may be the best attitude to directly or indirectly promote the development of disciplines. Of course, professional practitioners will never give up the efforts to make it perfect.

I sincerely hope that there will be fewer and fewer sad and heartbreaking stories.

Finally, I wish you all good physical and mental health.

References

[1] World Health Organization. (2018). ICD-11, the 11th Revision of the International Classification of Diseases. Geneva: World Health Organization; Available at: https://icd.who.int/.

[2] World Health Organization. (1989). ICD-10, the 10th Revision of the International Classification of Diseases. Geneva: World Health Organization; Available at: https://icd.who.int/.

[3] American Psychiatric Association (APA). (2013). Diagnostic and statistical manual of mental disorders, 5th ed. Washington: American Psychiatric Association.

[4] American Psychiatric Association (APA). (1994). Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Washington: American Psychiatric Association.

[5] American Psychiatric Association (APA). (2000). Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR®. Washington: American Psychiatric Association.

[6] Foucault, M. (1967). Madness and Civilization: A History of Insanity in the Age of Reason. Pantheon Books, New York.

[7] Allsopp, K., Read, J., Corcoran, R. & Kinderman, P. (2019). Heterogeneity in psychiatric diagnostic classification. Psychiatry Research, 279, 15-22.

[8] Rounsaville, BJ, Alarcon, RD, Andrews, G., et al. (2002). Basic nomenclature issues for DSM-V. In: Kupfer, DJ, First, MB & Regier, DE (eds). A research agenda for DSM-V, (1-29). Washington: American Psychiatric Association.

[9] Oldham, JM (2015). The alternative DSM-5 model for personality disorders. World Psychiatry, 14(2), 234-236.

[10] Krueger, RF, Hopwood, CJ, Wright, AGC, et al. (2014). Challenges and strategies in helping the DSM become more dimensional and empirically based. Curr Psychiatr Rep, 16, 515.

[11] Skodol, AE (2014). Personality disorder classification: stuck in neutral, how to move forward? Curr Psychiatr Rep, 16, 480.

[12] Bannister, D. (1968). The logical requirements of research into schizophrenia. Br. J. Psychiatry, 114, 181–188.

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