Considering the growing sense of ambivalence about the merits of the DSM, the time seems right for the re-evaluation of nosological attempts and efforts in the pre-DSM era. One example of these attempts is the CHAM system developed by the Dutch psychiatrist R.M. Silbermann (1932–1976). This system is intended as a simple classification with 20 “psychiatric states,” which are classified based on the presence of one of 12 hierarchically arranged core symptoms or key characteristics, while all “hierarchically higher” symptoms are excluded without inference about the “hierarchically lower” symptoms. Its scientific evidence is, as yet, insufficiently substantiated. However, disqualifying the CHAM system as an outdated Dutch folklore is like throwing out the baby with the bathwater. The CHAM system emerges as clinically straightforward, didactically fruitful, and consistent with more modern initiatives in descriptive psychopathology. Studying pre-DSM attempts such as Silbermann’s CHAM system can stimulate psychopathological thinking and serve as a source of inspiration for future phenomenological research in psychiatry.

© 2023 The Author(s). Published by S. Karger AG, Basel

“Es ist jedoch gefährlich, in der Psychopathologie einfach nur den Stoff zu lernen: man muß nicht Psychopathologie, sondern psychopathologisch beobachten, psychopathologisch fragen, psychopathologisch analysieren, psychopathologisch denken lernen. Ich möchte dem Studierenden helfen, sich ein geordnetes Wissen anzueignen; das bei neu beobachteten Phänomenen den Anknüpfungspunkt bietet, und das ihm ermöglicht, neu zu erwerbendes Wissen an seinen gehörigen “Ort” zu stellen.”1

Karl Jaspers [1]

The publication of DSM-III in 1980 represented “a giant leap” for psychiatry and the conceptualization of psychopathology. Theoretically neutral, evidence-based DSM categories appeared to provide a solid ground for the “via regia” of the origins of mental diseases. However, 4 decades later, despite the undisputable scientific advances, we are still nowhere near the understanding of the fundamental biological processes of most psychiatric disorders. Furthermore, as Andreasen [3] assumed, the DSM hegemony appears to have repressed the conceptual foundation of psychopathology from the awareness of the psychiatric community. To elude the “repetition compulsion,” now seems like the right time to reevaluate nosological attempts and efforts in the pre-DSM era. It is time for another “Copernican revolution,” that is, a paradigm shift from the assumption that “psychopathology must conform to DSM” to the supposition that “DSM must conform to psychopathology.”

Before the introduction of DSM-III in 1980, practically every country in the world had its own national classification system [4]. And in every country, almost every psychiatric institute had its own nosology at the behest of the local leading and most authoritative psychiatrist. One example of these local systems is the CHAM system developed in his PhD thesis [5, 6] by the Dutch psychiatrist Robert Silbermann (1932–1976) and his supervisor Piet Kuiper (1919–2002). In this article, the author will first briefly outline the background of the CHAM system. In the discussion, its relevance will be explored by answering three questions from a clinical perspective. What would be the merits of the CHAM system as a classification system? Could it serve as “a point of departure” for clinically relevant observations? To what extent would it enable us to gratify Jaspers’ wish “to set freshly acquired knowledge in its proper place” when applied as a didactic tool in medical education?

The acronym CHAM stands for Consistent, Hierarchical, Arbitrary, Monothetic [5, 6]. By “consistent” and “hierarchical,” Silbermann alludes to the consistent adherence to a hierarchy in what he believes to be the most important clinical symptoms. The hierarchy of symptoms is based on a ranking “from ‘ill’ to ‘less ill’ (perhaps a mostly esthetic factor)” (sic). Being primarily decisive for the estimation of severity seems to be the risk of somatic comorbidity/etiology, followed by the degree of cognitive, affective, and conative disturbance, respectively. Parenthetically, the qualification “consistent” seems redundant and may be intended to yield a biblical reference to Noah’s youngest son. “Arbitrary” as “taxonomic terminus technicus” is defined as “aimed at a certain purpose, not at random: the purpose is systematization of clinical decisions and actions.” “It is arbitrary but not wanton” (sic). The classification selection criteria were based on practicality and theoretical precision [7]. “Monothetic” refers to “the ruling idea” that groups “are formed by rigid and successive logical divisions so that possession of a unique set of characteristics is both sufficient and necessary for membership in the group thus defined.” Classification according to the CHAM system implies that one core symptom is consistently and unmistakably present, while “all ‘hierarchically higher’ symptoms are absent, and no statement is made as to the ‘hierarchically lower’ symptoms.”

With his PhD thesis [5, 6], Silbermann has tried to establish, in his own words, “a scientific approach to a practical problem.” The impetus was an increasing feeling of uneasiness about the manner in which diagnoses were established at the Psychiatric Clinic of the Amsterdam University Hospital and a growing diffidence of the diagnostic formulations.

In the Introduction, Silbermann advocated the replacement of the “ex cathedra” nosological systems by a diagnostic system of symptomatology based on a multicausal and multidimensional perspective without the assumption of a fixed link between etiological factors and symptoms. Following his principal and mentor Kuiper [7], Silbermann considered the diagnosis to be the pillar of a diagnostic process that contains the knowledge, obtained by observation and description of symptoms or “psychiatric states,”2 syndromes, and explanatory causal factors. As a possible impediment of this process, Silbermann identified the ambiguity of the meaning of the term “syndrome” and the nature of the available information, the noncircumscribed definitions, the lack of a complete list of known syndromes, and the unavailability of a standard diagnostic procedure for establishing a syndrome diagnosis. Therefore, Silbermann suggested, as a first step in the psychiatric diagnostic process, the cross-sectional establishment of “psychiatric states” based on a pragmatic classification system of psychiatric symptoms with clear criteria and a solid procedure. He defined a “psychiatric state” as “the totality of symptoms present at a given moment” and a syndrome as “a cluster of symptoms, i.e., a group or complex of symptoms which occur in combination relatively often.”

Using several common clinical terms, supplemented with designations from various textbooks and manuals, Silbermann compiled a provisional list of more than thirty symptoms. Based on the definition of mandatory and optional symptoms, which are directly observable during the psychiatric examination, he subsequently reduced this list to 27 “psychiatric states.” After comparing the definition of each “psychiatric state” used in the CHAM system with descriptions in various manuals and textbooks, Silbermann concluded that these definitions generally concurred sufficiently with the literature.

An exploratory study among a group of experts, consisting of Kuiper as the department head and 10 staff psychiatrists, eventually resulted in a list of 20 “psychiatric states” based on 12 hierarchically arranged clinical core symptoms (Table 1). The result of this exploratory research that “the mutual agreement and the constancy of the judgments were sufficiently great,” according to Silbermann, justified the conclusion that “the definitions used in the CHAM system concur with the average images that these terms invoke in the minds of clinical experts.”

CHAM system: core symptoms and psychiatric states [5, 6]

In a subsequent study, three different procedures were compared when choosing from 21 different categories. This concerned the normal clinical use of the “free choice,” “identification according to the CHAM system,” and a “mathematical identification procedure” using an “X-8 computer from the Mathematic Center in Amsterdam.” The data were transferred to punched cards.

The algorithm applied was based on the (mean) probabilities between symptoms and syndromes/diagnoses as reported by the same clinicians who also performed the “free choice.” The agreement between the CHAM system and the “free choice” (κ = 0.34 [p < 0.001]) was virtually equal to the agreement between the CHAM system and the “mathematical procedure” (κ = 0.35 [p < 0.001]). According to Silbermann, the agreement between the “free choice” and the “mathematical procedure” (κ = 0.24 [p < 0.001]) was “significantly” lower. Silbermann concluded that the CHAM system was sufficiently close to clinical reality. Without further statistical processing, Silbermann inferred that the experimental use of the CHAM system did not improve inter-doctor agreement and that diagnostic inconsistencies persisted even when dealing with symptoms that were “unmistakably present.” Silbermann assumed that the explanation for this was “the difficulty (to which a large number of factors contribute) of the clinical assessment of psychiatric symptomatology.”

The CHAM system, according to Silbermann, was intended as “a simple classification, without many pretensions,” in which no more was classified “than can be classified according to the actual knowledge at some point.” His aim was to develop an objective method to determine “unmistakable” symptoms, realizing that determining “psychiatric states” engenders “a limited but unambiguous communication.” He hoped that the CHAM system would change the situation where almost every clinic had its own diagnostic system. At present, that situation has improved significantly since DSM-III. However, considering the growing ambivalence toward DSM-5, it is conceivable that pluriformity will recur sub rosa as idiosyncratic “shadow” diagnoses in addition to official DSM diagnoses.

The CHAM system is restricted to symptoms that can be “unmistakably” identified by the clinician “at a given moment.” According to Gittleson [8], this also constitutes the weakness of the system. In his review of the English edition of Silberman’s thesis [6], Gittleson [8] considered it unlikely that British psychiatrists would ever categorize patients on the strict phenomenology of a single cross-sectional clinical picture. At the same time, Silbermann’s symptom hierarchy appears to be complementary to new contemporary initiatives like the dimensional and transdiagnostic Hierarchical Taxonomic of Psychopathology (HiTOP) model [9, 10]. This descriptive phenomenological model was developed based on factor-analytic data from quantitative nosological research. The HiTOP model distinguishes five levels, which are hierarchically arranged from general to specific: “superspectra” (“p factor” or general psychopathology factor); “spectra” (e.g., “internalizing,” “detachment”); “subfactors” (e.g., “fear,” “distress”); “syndromes/disorders”; and “symptoms, signs, and personality traits.” The level of the “psychiatric states” of CHAM is situated, as it were, between the two levels mentioned last. In this sense, the CHAM system could be regarded as an enhancement of the resolution of the HiTOP model.

The CHAM system refers to the diagnostic stage preceding the stage to which the DSM refers. In this sense, the CHAM system could be regarded as a conceptual organizing and presorting principle preceding the first step (“engage in watchful waiting”) of the “stepped diagnosis” strategy [11]. The descriptive phenomenological approach of the CHAM system does not specifically address the developmental stage or severity level but, like the HiTOP model, could enrich the clinical staging of psychiatric pathology (cf. [12]).

By choosing “psychiatric states” as a diagnostic starting point, Silbermann joined the critic faction of Kraepelin’s concept of “disease entities.” Following Guislain [13] and Kahlbaum [14], Wernicke [15] suggested the mental state (“Zustandsbild”) as a provisional nosological construct. The “psychiatric state” defined by Silbermann corresponds to the symptom complex of Hoche [16]. In a lecture for the German Psychiatric Association, this opponent of Kraepelin “assumed with certainty that in the physiological regard there will be just as little possibility of clear-cut differentiation as in the psychological” without inventing “logical-dialectical fictions.” In his view, symptom complexes should be regarded as “units of the second order” (“Einheiten Zweiter Ordnung”) between the so-called forms of illness (“sog. Krankheitsformen”) and the elementary symptoms (“Elementarsymptome”) [17]. The focus on “states” is quite compatible with the now growing insight that experiences like depression and psychosis are viewed as states within a dynamic systems theory perspective, moving away from the idea of stable nosological entities.

The CHAM system consists of 20 “psychiatric states.” Half a century after the publication of Silbermann’s thesis, the number of DSM diagnoses has increased from 228 in DSM-III to 541 in DSM-5, whereas the number of categories defined using diagnostic criteria has dropped from 163 to 151 [18]. Over the last few decades, there has been a growing sense of ambivalence about the merits of the DSM and its “splitting” tendency, which produces an abundant number of categories. The CHAM system concurs with the propositions of “lumpers” such as Southard [19] who suggested reducing the main groups of mental illnesses to 11 categories. More recently, in the Netherlands, van Praag [20] suggested to roughly classify psychiatric syndromes into broad “basins,” and Tan and van Os [21] considered reducing the number of DSM-5 categories “to 20 broad syndromes (at the chapter level).” The hierarchy of CHAM core symptoms is in harmony with the DSM-IV chapter index (Table 1). Contrastingly, in the DSM-5, this structure was dropped. To illustrate, “elimination disorders” are placed between “feeding and eating disorders” and “sleep-wake disorders.” “Substance-related and addictive disorders” and “neurocognitive disorders” have been moved to the back, in between “disruptive, impulse-control, and conduct disorders” and “personality disorders.” The DSM-5 structure may be more in line with scientific research, but it is also less in keeping with the clinician’s line of reasoning. This is probably one of the reasons for the increased ambivalence among clinicians.

Silbermann’s research project is subject to several limitations. The methodology surely does not stand up to EBM scrutiny. The small sample size of 1 head of the department and 10 staff psychiatrists limits the generalizability of the results. The sample of the exploratory study and the comparison study consisted of a small group of direct colleagues and was therefore prone to participant (friendliness and social desirability), selection, and information bias. One of the main drawbacks is the hierarchy of symptoms. Clinical validity seems plausible and is based on clinical significance, as indicated by the urgency and severity of psychopathological disintegration. However, from a modern EBM perspective, the establishment of the hierarchy seems scientifically invalid. Although considered “the most important principle,” the hierarchy was based on the clinical experience and intuition of the author instead of statistical analysis. Interestingly, the author appeared to be aware of this flaw, judging by the comment in brackets: “perhaps a mostly esthetic factor.”

By comparing the 3 different procedures, Silbermann probably hoped to develop a kind of “clinical decision support” system. His conclusion that the CHAM system was sufficient in keeping with the clinician’s line of reasoning seems premature. An (unweighted) kappa of 0.34 with only 45% observed agreement implies that the agreement is very limited. Furthermore, a 95% confidence interval is missing, which means that it cannot be simply inferred that 0.24 is lower or even “significantly” lower than 0.35. The question here is whether a connection to the clinical routine could be expected: the CHAM system is a classification of “psychiatric states” and not a classification of disease entities. The latter was also apparent from Silbermann’s description of some common forms of mismatch between the CHAM classification and the “free choice” classification. In short, the results of the empirical research are not very convincing. However, the limited ICT facilities, including Hollerith cards, can be considered as an extenuating circumstance.

The proverbial beauty lies in its simplicity. In contrast to the 151 DSM-5 categories, the CHAM system includes 20 “psychiatric states” fitting on the front of a T-shirt. In particular, in acute situations, the CHAM system can be useful as a quick scan or “snapshot” [11] to bring order to complex and usually incomplete diagnostic information. Limiting oneself to the assessment of the momentary “psychiatric state” can prevent exegetical discussions. Meanwhile, awareness of the risk of CHAM-induced cognitive bias (e.g., framing, confirmation bias, priming effect, inattentional blindness) is mandatory.

In addition, the CHAM system could be useful as an educational tool. Medical students often experience the subject area of psychiatry as inconceivable or vague and difficult to integrate with the rest of medicine. Using DSM as a primary textbook or main diagnostic resource in psychiatric teaching can culminate in a sense of “information overload.” Consequently, many students stick to mindlessly memorizing the DSM criteria and reciting symptoms on their exams. As Andreasen [3] noticed, the hegemony of DSM in training programs and health care delivery systems has led to a steady decline in the teaching of careful clinical evaluation aimed at the problems of the individual and the social context at the expense of psychopathological insight and knowledge.

Using the CHAM system can be advantageous for students by helping them discern the basic principles and logical structure of psychopathological symptomatology. The CHAM system is consistent with the trichotomous model of the mind (cognitive-affective-conative), Plato’s conception of the soul (logos [reason], thymos [spirit], eros [desires]), and Freud’s psychodynamic structural model (Über ich-Ich-Es). Therefore, the use of the CHAM system will contribute to the gratification of Karl Jaspers’ wish by stimulating students to learn, observe, and think psychopathologically in order to acquire “a well-ordered body of knowledge.”

Silbermann’s CHAM system refers to the diagnostic stage preceding the stage to which the DSM refers. The CHAM system is merely intended as a simple and preliminary classification and a presorting first step in the psychiatric diagnostic process. The simple clinical applicability and compatibility with the trichotomous model of the mind could argue in favor of the CHAM system despite the insufficient scientific evidence and new contemporary initiatives in the field of descriptive psychopathology. Disqualifying the CHAM system as prehistoric or outdated Dutch folklore is like throwing out the baby with the bathwater. Studying pre-DSM attempts such as Silbermann’s CHAM system can be a stimulus to understand basic psychopathological principles of psychiatric diagnostics and a source of inspiration for future phenomenological research.

The author would like to thank Prof. Dr. Wim van den Brink for his invaluable expert opinion on the statistical analysis as described in Silbermann’s thesis.

The author has no conflicts of interest to declare.

The author did not receive any funding.

The manuscript of the article has been written by Herman N. Sno.

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