East Asian Arch Psychiatry 2012;22:75-81

COMMENTARY

The Gradation of Psychopathology: for Better or for Worse

精神病理学的变化取向评估：孰好孰坏？

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Prof. Dusan Kecmanovic, MD, PhD, European Academy of Sciences and Arts, Salzburg, Austria.

Address for correspondence: Prof. Dusan Kecmanovic, P.O. Box 736, Newtown, NSW 2042, Australia.
Tel/Fax: (61-2) 9557 0854; email: dkecmanovic@gmail.com

Submitted: 19 January 2012; Accepted: 2 April 2012

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Introduction

A categorical system assigns mental syndromes to categories. On the other hand, a dimensional system classifies clinical presentations based on quantification of attributes rather than assignment to categories.¹

The notion of psychopathological phenomena as phenomena that are given on a continuum — from healthy states to slight deviations from the ‘normal’ and from moderate to severe pathological disturbances — has been around for 100 years.² Yet mental disorders have been presented as discrete and distinct entities, meaning as categories, in the DSM-III and DSM-IV of the American Psychiatric Association.^3,4 The DSM constitutes the first time that psychiatric syndromes were operationally defined in an attempt to enhance reliability and validity of psychiatric diagnoses.

Several circumstances paved the way for the construction of the DSM-III and DSM-IV. The psychiatric community was taken by surprise when Kendell et al⁵ published the results of the examination of psychiatric diagnostic practice on both sides of the Atlantic in 1971. After interviewing the same patients, psychiatrists in New York City diagnosed the patients’ mental problems as indicative of schizophrenic disorder twice as frequently as their colleagues in London, who said that the patients diagnosed as having schizophrenic disorder by the American psychiatrists actually had depressive disorder, personality disorder, and neurotic disorder. These findings rang an alarm. The question was raised: can we trust psychiatrists? What is psychiatric diagnosis all about? Thus, the task of making psychiatric diagnosis more reliable, preferably as reliable as is the diagnosis in somatic medicine, emerged as a matter of priority. The more so as the courts and health insurance companies also exercised pressure on psychiatrists to do their best to increase the reliability of the diagnosis of mental disorders. The categorical presentation of psychiatric disorders was regarded as the right way to achieve this goal.⁶ Moreover, antipsychiatrists in the 1970s argued that psychiatrists had labelled social dissenters as mentally ill to discredit them. Hence, a diagnosis of generic mental disorder that would impede labelling of political dissidents as mentally disordered, and thereby help psychiatry to reaffirm or regain the status of a medical discipline, was badly needed. The DSM-III and DSM-IV operational definition of generic mental disorder was an answer to this need.

However, the disease entity assumption that conceptually makes the foundation of the DSM-III and DSM-IV has been increasingly questioned.^7-10 At the same time, the idea of the dimensionality of psychopathological phenomena has been promoted by an ever greater number of psychiatrists and psychologists.^11-14 Thus, in preparation for the DSM-V that is due to be published in 2013, the consideration of “the advantages and disadvantages of basing part or all of DSM-V on dimensions rather than categories” was highly recommended.¹⁰

One can only guess which circumstances might have recently put the dimensional concept of psychopathology so high on the psychiatric agenda. It is likely that 3 circumstances are most responsible for the challenge to the categorical concept of mental disorders. The first one is the ever more evident imperfections of the categorical model and, by the same token, of the DSM-III and DSM-IV.^15-17 Second, the growing awareness of psychiatrists that boundaries between individual psychopathological syndromes, least of all between normal and pathological, are not as clear-cut and fixed as was previously believed.¹⁸ Third, “with recent innovations in statistical methods and research practices, it has become clear that psychopathology can be viewed not only as absent or present, but dimensionally via measures such as frequency and severity that can assist in determining a therapeutic path.”¹⁹

This paper highlights the advantages and disadvantages of the categorical and dimensional concepts, and determines which concept is more useful in clinical practice and beyond.

Advantages of the Categorical Concept

Clinical Utility

The categorical concept is easy to use. It is convenient for clinical practice because it conveys unequivocal information about whether an individual is mentally ill or healthy, and what disorder is present. Therefore, this concept provides clear guidelines regarding the need for treatment of a particular person.

Utility beyond Immediate Clinical Practice

The categorical concept is markedly useful in legal matters (criminal or civil responsibility), as well as in matters related to the insurance industry. The concept better fits reimbursement policy. Also, it is preferable to the dimensional concept for professional communication.²⁰

Imperfections of the Categorical Concept

One cannot overestimate the weaknesses of the categorical polythetic concept that has been used in the DSM-III and DSM-IV, and in the International Classification of Diseases (ICD-10).²¹ A few of them will be pointed out as the following discussion shows.

Co-morbidity

The notion of co-morbidity indicates that patients meet criteria for more than one specific diagnosis. If patients frequently meet criteria for more than one specific diagnosis, this suggests that something might be wrong with the concept of generic mental disorder used in the respective classification and / or with the definition of individual mental disorders. It is noteworthy that fitting a syndrome into one, and only one, diagnostic ‘pigeonhole’ is one of the basic requirements that a diagnostic and classificatory system should meet.

Within-category Heterogeneity

The polythetic-type diagnosis of a specific disorder says that a patient should have a number of all-listed symptoms to meet the criteria for a distinct disorder. As a result of such a diagnostic construct, patients who meet the criteria for a specific diagnostic entity may have little in common as far as their symptoms are concerned.²² Accordingly, patients having the same diagnosis may vary significantly in terms of the response to treatment and prognosis.

Subthreshold Disorders

Wherever the line is drawn between a disorder and non- disorder, those phenomena that are just below the line cannot help but would be of much interest to those who deal with the phenomena that have been classified. Subthreshold disorders are those disorders that satisfy a number of, but not all, the criteria of the respective disorder. The more subthreshold disorders there are within a classification, the more the classification is deficient.²³ The categorical system does include a great many subthreshold disorders.

Overlooking of Individual Differences

The categorical concept by definition ignores the way in which individuals experience mental disturbance as well as the severity of symptoms.²⁴

Advantages of the Dimensional Concept

Importance of Intermediate States

Those who advocate the dimensional concept argue that psychopathology cannot be viewed only as absent or present. There are many intermediate states between these 2 extremes, and such states are heuristic for they shed light on the nature of psychopathology. Also, intermediate states might be of help in studying the genesis of psychopathology and its fluctuations.

More Individual Specific Information

The dimensional concept supplies psychiatrists with much more information regarding the patient than does the categorical concept. Also, the information provided is more

specific and more precise than that the categorical concept can confer because it relates to a specific individual rather than to a group or category of people covered by the same diagnosis.

Boundaries do not Matter

The dimensional concept does not imply the claim that the boundaries between the normal and the pathological, as well as between individual mental disorders, can be identified. It avoids “the misleading, unstable, and illusory efforts to carve psychological functioning at non-existent discrete joints.”²⁵

How to Follow the Course of a Disorder

By using the dimensional concept, psychiatrists can follow “changes across the course of a period of mental disorder for an individual”,²⁶ and can thus make their treatment decisions both person-specific and based on numeric data. It is of note that quantification of the severity and frequency of symptoms is at the heart of the dimensional concept.

Imperfections of the Dimensional Concept

There are several deficiencies of the dimensional concept that should be pointed out when comparing this and the categorical approach to psychiatric diagnosis.

Number and Comparative Diagnostic Significance of Individual Dimensions

Each psychiatric syndrome can be defined along a great number of dimensions. So the question arises as to which dimension(s) should be taken into account when presenting clinical manifestations on a continuum. Moreover, if a psychiatric syndrome is defined along several dimensions, will all dimensions have the same diagnostic significance in determining the nature of a particular syndrome, or should a hierarchy of diagnostic importance of the individual dimensions be established?

Impracticality of the Dimensional Concept

As noted by Sartorius,²⁷ “the problems with a dimensional classification is that the making of a diagnosis — i.e. the profile of a patient on a fixed number of dimensions — might take a long time and would require the application of a number of psychometric instruments which the psychiatrists and other medical staff are unlikely to use.” Besides, the experience with the multi-axial version of the ICD and with the 5 axes of DSM-III and DSM-IV has demonstrated that psychiatrists most often use only 1 axis, the one for basic diagnosis. “It is therefore difficult to imagine that they would be willing to rate a large number of dimensions for each patient.”²⁸

Thus, if the dimensional model is impractical, its clinical utility is questionable. What is the point of constructing the dimensional system if clinicians do not find it useful in day-to-day clinical practice?²⁹

Difficulties in Administration and Collecting Vital Statistics

If a dimensional concept is adopted, it will complicate medical record keeping and the collection of vital statistics. More importantly, such a concept would make the diagnosis of mental disorders, as well as of general medical conditions disparate.³⁰ The different ways in which diagnosis of mental disorders and of general medical conditions would be articulated could not help but to further distance psychiatry from the rest of medicine. Nowadays, that is the last thing that the majority of psychiatrists would like to see.

Which Way to Go?

Kupfer, Chairman of the DSM-V Task Force, has touted the upcoming DSM-V as a ‘paradigm shift’ in diagnosis,³¹ meaning a shift from the categorical concept to the dimensional one. If such a shift really occurs, it will represent a fundamental change in the conceptualisation of psychopathology in an official classification of mental disorders. At this stage, however, “it does not appear that this shift will in fact occur.”³² If true, this indicates that the dilemma — categorical or scalar approach — is far from being resolved.

Maybe the resolution of this dilemma should not be formulated in ‘either-or’ form. It could be argued that open-mindedness to both the categorical and dimensional concepts is preferable to disregarding either of them.²⁰

Also, it could be pointed out along the same lines that it is a false assumption that the disorder is either categorical or dimensional. “In a real sense, every disorder is both. It is either present or not (categorical), but when the disorder is present, patients may vary with respect to the age of onset, severity, symptomatology, impairment, resistance to treatment, and a variety of other disorder characteristics (dimensional). When the disorder is not present, subjects may vary in susceptibility to that disorder and may well express some of its symptoms to some degree.”¹ In other words, there is enough room for dimensions within a categorical approach — when the disorder is there, and even when there is no disorder.

Since the dimensional concept is seen as corrective of the categorical one, it is appropriate first to assess whether, and if so, how much, the dimensional concept redresses the deficiencies of the categorical approach, and second, if the dimensional approach in itself and of itself creates some practical and theoretical problems.

The Quality-quantity Question

The basic difference between the categorical and dimensional concept can be reduced to the difference between ‘kind’ and ‘degree’. According to the categorical model, each individual form of psychopathology, as well as what is considered as normal or pathological, is qualitatively distinct. On the other hand, the dimensionalists argue that the only difference between the above phenomena is the difference in degree, that is, in quantity.

It is hard to acknowledge that the continuum implies qualitative sameness of states that appear on different points of the continuum. Greater or weaker intensity, or high or low frequency of a psychopathological phenomenon, to name just 2 possible dimensions, is quite often accompanied by a new quality of the respective phenomenon. One philosophical problem remains for the dimensionalists — after a certain point, changes in quantity become changes in quality.³³

Dimensionalists claim that there is difference only in degree “when an individual is certain that they could not be mistaken and will not countenance any alternative explanation for their experience” and “when one feels very confused and uncertain about their ideas and readily want to think about alternative accounts of their experiences”.³⁴

Everyday experience and clinical practice show, however, that this is not the case. These 2 forms of relating towards one’s ideas differ in kind. They do differ in regard to the intensity of people’s clinging to their ideas. Yet, different intensities of holding on to particular ideas originate from qualitatively different mental states and result in qualitatively different mental conditions and activities of the respective individuals.

For example, there is the Clinician Rating Scale for Psychosis in the DSM-V proposal.³⁵ According to this rating scale, psychosis as manifested over the last 2 weeks, by delusions, hallucinations, or disorganised speech, can be not present, equivocal, present but mild, present and moderate, and present and severe. The severity and additional duration measure has been used to assess severity of psychosis components such as hallucinations, delusions, disorganisation, abnormal psychomotor behaviour, restricted emotional expression, avolition, impaired cognition, depression, and mania. Thus, delusions can be not present, equivocal (severity or duration not sufficient to be considered psychosis), present but mild (delusions are not bizarre, or little pressure to act upon delusional beliefs, not very bothered by beliefs), present and moderate (some pressure to act upon beliefs, or is somewhat bothered by beliefs), and present and severe (severe pressure to act upon beliefs, or is very bothered by beliefs).

It is of note that nowadays a number of authors grade delusions, in other words, talk about various degrees of delusions. They use different terms for ‘not true’ delusional beliefs / ideas, for example, ‘psychotic-like experiences’,³⁶ ‘mild psychotic experiences’,³⁷ ‘partial delusions’,³⁸ ‘questionable delusions’,³⁹ and ‘less severe delusions’.¹³

Such a deconstruction of delusions is based on 2 premises that first, there are gradations of delusions, and second, there are only quantitative differences between various degrees of delusions. However, it is highly debatable whether, for example, equivocal presence of delusions, or when delusions are present but mild, and when they are present and severe, is the same in a qualitative sense, that is, in terms of subjective experience. Briefly said, are ‘questionable delusions’ or ‘less severe delusions’ still delusions? Subsequently, is an equivocal, that is ‘yes and no psychosis’, still psychosis?

The Threshold Question

To determine the threshold above which a psychological phenomenon becomes psychopathological is an arbitrary and value-laden act. Since the categorical approach implies the existence of discrete entities, it includes the acknowledgement of a dividing line between individual disorders, as well as between normality and pathology. Yet advocates of the dimensional model, as mentioned above, criticise the categorical approach, among others, because they contend that individual psychopathological as well as normal and pathological phenomena are given on a continuum, that is, they are not discontinuous data.

One might say that the statement that most forms of psychopathology manifest both continuous and discontinuous relationships with other phenomena is closest to the mark. However, this does not mean that dimensional relationships, which any form of psychopathology has with other phenomena, are threshold-free. For example, if the intensity of depression is one of the dimensions of major depressive disorder, psychiatrists have to know how high intensity of depression indicates that anti-depressant or cognitive-behavioural or any other form of treatment is needed. In other words, psychiatrists have to know where is the threshold of intensity of depression above which psychiatric treatment is warranted. The same holds for psychotic symptoms such as delusions and hallucinations. If we consider them scalar rather than categorical, we still have to determine the point on a scale of the intensity of holding a particular idea or belief (intensity of conviction) at which that particular idea or belief deserves the attribute delusional. As David² put it, it soon becomes evident after only a cursory perusal of the literature that even workers motivated by the idea of a continuum find it impossible to resist setting a threshold above which a hallucination or delusion may be defined.

In the domain of social phobia, a numerical continuum has been imported — how many situations one is afraid of. Thus, if someone is scared of 1 or 2 specific social situations he / she is said to have performance anxiety, which is also called non-generalised social anxiety disorder. Yet, if there are many social situations in which one gets markedly anxious, he / she will be diagnosed with generalised social anxiety disorder. So, on the quantity continuum a threshold has been set — 1 or more social situations vs. more than 2 social situations — so as to differentiate, or more accurately, to inaugurate 2 apparently different disorders. Even the dimensional concept cannot do without thresholds.

Blurring the Distinction between Normal and

Pathological

The dimensionalisation of psychopathology, that is the argument that ‘degree’ rather than ‘kind’ matters, puts in question the dividing line between the sane and the insane. According to the currently dominant concept, psychopathological phenomena differ from normal psychological ones, both in degree and kind. The pathological deviates from the standard (normal), but it is also qualitatively different from the normal. If we deny the specific quality of phenomena, such as the psychotic experience, then we lose track of the difference between the sane and the insane.

Johns and van Os⁴⁰ wrote that the implicit assumption of the dimensional approach is that “experiencing symptoms of psychosis such as delusions and hallucinations is not inevitably associated with presence of disorder.” What does it mean? It means that “in many cases, psychotic symptoms may fall within the spectrum of normal experience.”³⁶ If that is the case, then I would argue that normal and pathological gets mixed up. By the same token, one of the basic principles of psychopathology (the difference between normal and pathological) is challenged. “The problem is, that if one allows a delusion to be characterised by ‘stated with some degree of conviction, from probability to absolute certainty’, then the definition of delusions, which rests on the epistemological degree of certainty, will collapse.”⁴¹

Moreover, it should be noted that “independent of the question whether dimensional, categorical or typological classifications of mental disorders better correspond to the real situation, any dimensional systematic becomes categorical or typological if certain degrees of expression of certain behavioural patterns are rated as ‘mentally healthy’ or ‘mentally ill’, or as diagnostically, therapeutically or prognostically relevant, on the basis of statistical averages.”⁴²

Here is another example of how the dimensional approach may render the distinction between the normal and the pathological difficult. Personality disorder is regarded as a phenomenon between normal and psychopathological. How have personality disorders been conceptualised in the DSM-V proposal?⁴³ It is said that the presence of a personality disorder should be assessed on the basis of impairment in personality functioning and presence of pathological personality traits. The impairment in personality functioning is being defined dimensionally. It is determined by the severity of disturbances in self- functioning and interpersonal functioning. The first is composed of identity and self-direction. So what are the grades of the disturbances in identity like? There are 4 of them defined in terms of impairment severity. Here is the description of the least severe disturbance in identity: “relatively intact sense of self, with some decrease in clarity of boundaries when strong emotions and mental stress are experienced. Self-esteem diminished at times, with overly critical or somewhat distorted self-appraisal. Strong emotions may be distressing, associated with a restriction in range of emotional experience.”⁴³ This kind of disturbance in self-identity seems to be more normal than pathological; it represents one of the many variations of self-identity in normal persons. The description of features of a mild degree of impairment in self-direction, in interpersonal functioning (empathy and intimacy), and in regard to trait facets, is made along similar lines, indicating that the given person is more on the side of normality than pathology. Thus, it is questionable whether a person with such characteristics should be diagnosed with a personality disorder. Needless to say, a personality disorder of mild degree is still a personality disorder.

Conclusion

Both the categorical and dimensional concepts have their strengths and weaknesses. Also, as shown in the text, each of them has its advocates and its critics. One may say that the main advantages of the dimensional concept are the key disadvantages of the categorical approach, and vice versa. Thus, the main advantage of the dimensional concept over categorical systems is that it provides more information about the condition of a particular patient, and thereby supplies psychiatrists with more details regarding a patient’s current mental state. Yet the main imperfection of this model is that it denies qualitative difference between various mental states, which apparently have so much in common that they can be conceived on a continuum. By doing this, the dimensional model puts wear and tear of everyday life and pathological experience on the same footing and ultimately disputes the feasibility of differentiating the insane from the sane.

Yet the utility of the dimensional concept in clinical practice is debatable, in that it is difficult to know which dimensions are most useful and accessible to measurement; it may obscure what could, in fact, be distinct and independent categories^33,44-46; dimensions are not diagnosis-specific⁴⁷; it will be extremely difficult to “define the particular dimensions (and their hierarchical arrangement) that seem most valid and suitable for clinical use”²⁹; transitioning from a categorical to a dimensional DSM would be disruptive because it would involve radical changes in the diagnostic groupings, individual diagnostic entities, and diagnostic assessment procedures³⁰; and the making of a diagnosis, i.e. the profile of a patient on a fixed number of dimensions, might take a long time and would require the application of a number of psychometric instruments, which psychiatrists and other medical staff are not likely to use.²⁷ Thus, dubious clinical utility of the dimensional concept is “a compelling argument for retaining categorical distinctions in the nosology.”⁴⁸

Such a view of the categorical and dimensional approach seems to have prevailed among scholars who are in charge of the preparation of DSM-V. These scholars have dubbed their proposal the ‘cross-cutting dimensional assessment in DSM-V’. The proposal indicates that DSM-V’s planners are keen on keeping the existing categorical diagnoses in DSM-V, saying that “dimensional assessments are being proposed for inclusion with existing categorical diagnoses in DSM-5 to provide a basic measurement-based care.”⁴⁹ They added, “the aim of the

assessment is to provide quantitative measures of important clinical areas (such as depressed mood, anxiety, substance use, or sleep problems) that will be relevant beyond any set of syndromal criteria…It relies whenever possible on self-rating by a patient or informant.” (The assessment is called ‘cross-cutting’ because these measures cut across the boundaries of any single diagnosis.)

From the above-said, in DSM-V, the dimensional approach is not likely to challenge categorical diagnoses, which will most likely stay as the cornerstone of this new version. After all, a successful revolution in the sense of the establishment of a new paradigm “requires not only widespread dissatisfaction with the old paradigm, but the emergence of a compelling new one that addresses successfully its predecessor’s limitations.”⁵⁰ Such a new diagnostic paradigm has not appeared yet.

Goldberg⁵¹ seems to be closest to the mark when — after comparing the categorical approach, which he dubs the Platonic approach, to the dimensional approach, which he dubs the Aristotelian approach — he concludes: “Plato is the best we have, provided that we remember not to take him seriously.”

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