Concepts of disease: their relevance for psychiatric diagnosis and classification

The schizophrenia syndrome, circa 2024: What we know and how that informs its nature

With new data about different aspects of schizophrenia being continually generated, it becomes necessary to periodically revisit exactly what we know. Along with a need to review what we currently know about schizophrenia, there is an equal imperative to evaluate the construct itself. With these objectives, we undertook an iterative, multi-phase process involving fifty international experts in the field, with each step building on learnings from the prior one. This review assembles currently established findings about schizophrenia (construct, etiology, pathophysiology, clinical expression, treatment) and posits what they reveal about its nature. Schizophrenia is a heritable, complex, multi-dimensional syndrome with varying degrees of psychotic, negative, cognitive, mood, and motor manifestations. The illness exhibits a remitting and relapsing course, with varying degrees of recovery among affected individuals with most experiencing significant social and functional impairment. Genetic risk factors likely include thousands of common genetic variants that each have a small impact on an individual's risk and a plethora of rare gene variants that have a larger individual impact on risk. Their biological effects are concentrated in the brain and many of the same variants also increase the risk of other psychiatric disorders such as bipolar disorder, autism, and other neurodevelopmental conditions. Environmental risk factors include but are not limited to urban residence in childhood, migration, older paternal age at birth, cannabis use, childhood trauma, antenatal maternal infection, and perinatal hypoxia. Structural, functional, and neurochemical brain alterations implicate multiple regions and functional circuits. Dopamine D-2 receptor antagonists and partial agonists improve psychotic symptoms and reduce risk of relapse. Certain psychological and psychosocial interventions are beneficial. Early intervention can reduce treatment delay and improve outcomes. Schizophrenia is increasingly considered to be a heterogeneous syndrome and not a singular disease entity. There is no necessary or sufficient etiology, pathology, set of clinical features, or treatment that fully circumscribes this syndrome. A single, common pathophysiological pathway appears unlikely. The boundaries of schizophrenia remain fuzzy, suggesting the absence of a categorical fit and need to reconceptualize it as a broader, multi-dimensional and/or spectrum construct.

How to define today a medical disorder? Biological and psychosocial disadvantages as the paramount criteria

BACKGROUND

The 20th century has seen great developments in the concept of disease. Marked by the biopsychosocial paradigm, several strategies for disease definition were added to previous descriptive organic views, but a final concept is still out of reach.

METHOD

A critical review was carried out on thorough analysis of articles and textbooks to describe the main concepts and definitions of disease.

RESULTS

The concept 'disease' is a pragmatic construct, not a natural kind. Three main ways to define disease were identified, and characterized: Biological (disease as a lesion, disadvantage/deviation from normal and dysfunction), Psychosocial (distress and disability, existential potentials, descriptive prototype, and prototype typification), and values-based definition.

CONCLUSION

All the paradigms have advantages and flaws, but progressive use of all criteria in disease definition adds validity and reliability to diagnostic constructs. Such constructs must be, above all, useful for practice and research. Biological paradigm is relevant, but fails to cover all the complexity that involves human illness and the treatment process. An emphasis on distress, dysfunction, and carefully selected value-laden characteristics might be the right direction for useful diagnostic construct conceptions.

Epistemological implications of near-death experiences and other non-ordinary mental expressions: Moving beyond the concept of altered state of consciousness

During the last decades an increasing interest has developed in the so-called altered state of consciousness (ASCs); among these, near-death experiences (NDEs) are one of the most intriguing and debated examples. NDEs are deep and universal experiences with a clear phenomenology and incidence, while some of their features challenge the current views of human consciousness (focused on neural circuits and based on the concept of mind as a byproduct of brain circuitry) with relevant epistemological and historical implications. The origin of the ruling mechanist-reductionist paradigm can be traced back to Descartes' radical separation of res cogitans and res extensa and the conflict between the nascent science and the Inquisition; this led to removing the subjective properties of mind from the field of scientific interest, relegating them to philosophy and theology in order to enable the development of modern science. However, the physics of the 20th century has eventually moved beyond the classical paradigm, permitting a profound renewal of scientific interest in the mind. Modern research on NDEs has contributed to reopening the debate surrounding the Cartesian separation, the mind-brain relationship and the nature of consciousness. It is now time to reappraise the relevance, strengths, and weaknesses of the available scientific interpretations of NDEs, their relationship with other ASCs, as well as the very concept of ASC; the latter looks to be ill-founded, suggesting the need for: (a) a revision of the conventional approach to subjective phenomena, including both the third- and first-person perspective; and (b) a deep reflection on the possible links between different non-ordinary mental expression, as regards both their phenomenology and mechanisms from a non-pathological perspective.

Awareness and insight in psychopathology: An essential distinction?

In psychiatry/clinical psychology, the language of psychopathology remains the main clinical and research tool as it seeks to capture the clinical phenomena underlying mental disorders. It is thus important periodically to review it in order to clarify and refine its relationship to its referent phenomena. This paper argues for a fundamental distinction to be made, in a technical sense, between awareness and insight as, respectively, the narrower and wider form of self-knowledge patients have concerning their conditions.This distinction is based on differences between “objects” of such self-knowledge. Where “objects” refer to impairment of function, as in the neurosciences, the corresponding phenomenon of self-knowledge (awareness) is narrow, based on a direct appraisal of impairment, and evaluated quantitatively . Where “objects” refer to mental symptoms/disorders, as in clinical psychology/psychiatry, the corresponding phenomena of self-knowledge (insight) are wide, based on both direct and indirect appraisals of change, and are evaluated quantitatively and qualitatively. The technical distinction between awareness and insight is important because it differentiates between structural differences in phenomena, indicative of differences in underlying mechanisms, and in turn suggesting the need to adopt different approaches to their study.

DSM diagnosis and beyond: on the need for a hermeneutically-informed biopsychosocial framework

While often dubbed "the bible of contemporary psychiatry" and widely hailed as providing "a benchmark" for the profession, on closer inspection the DSM is seen to be shot through with philosophical assumptions that restrict its theoretical cogency and limit it clinical efficacy. Hence, in the interests of enhanced patient-care it is important to think critically about the DSM, with a view to maximising its diagnostic strengths while minimising its weaknesses. The critical analysis undertaken in the present paper underscores the importance of not construing the DSM as a self-contained diagnostic tool but of viewing it, rather, as an indispensable component in a more comprehensive, multidimensional diagnostic process. More specifically, the contention is that the DSM's diagnostic limitations evoke a biopsychosocial framework of application as their necessary corrective, notwithstanding the entrenched tendency to construe these approaches as oppositional. Further, it is contended that a hermeneutically informed biopsychosocial template has particular advantages as an integrating framework.

Pre-attentive auditory processing in ultra-high-risk for schizophrenia with magnetoencephalography

BACKGROUND

It is uncertain whether the neurobiological abnormalities in schizophrenia emerge at the first episode of the disorder or are present during the prodromal phase. Recent neuroimaging studies indicate that some brain abnormalities are present in subjects at ultra-high-risk (UHR) for schizophrenia. Pre-attentive auditory deficits, which represent a core feature of schizophrenia, were investigated in individuals at UHR for schizophrenia.

METHODS

We assessed early auditory processing indexed by the magnetoencephalographic mismatch negativity magnetic counterpart (MMNm) component elicited during a passive oddball paradigm in UHR individuals. Sixteen individuals at UHR for schizophrenia on the basis of clinical criteria and 18 healthy control subjects matched for age, gender, and education participated. A duration-deviant oddball paradigm was used to obtain MMNm dipole moment, which was measured with cortical source modeling.

RESULTS

The UHR group showed a smaller right MMNm dipole moment than those of the control group. Group difference was observed in MMNm dipole latency, suggestive of slowed processing. The left MMNm dipole moment was negatively correlated with clinical symptoms measured by the Comprehensive Assessment of At-Risk Mental States positive symptom score.

CONCLUSIONS

Our findings suggest that deficits in the early stage of auditory processing in individuals at UHR for schizophrenia exist before the onset of psychosis. The MMNm dipole moment might reflect the functional decline at the prodromal stage of schizophrenia.

Schizophrenia, "Just the Facts": what we know in 2008 part 1: overview

For every disorder, there is a set of established findings and accepted constructs upon which further understanding is built. The concept of schizophrenia as a disease entity has been with us for a little more than a century, although descriptions resembling this condition predate this conceptualization. In 1988, for the inaugural issue of Schizophrenia Research, at the invitation of the founding editors, a senior researcher, since deceased (RJ Wyatt) published a summary of generally accepted ideas about the disorder, which he termed "the facts" of schizophrenia. Ten years later, in conjunction with two of the authors (MSK, RT), he compiled a more extensive set of "facts" for the purpose of evaluating conceptual models or theoretical constructs developed to understand the nature of schizophrenia. On the 20th anniversary of this journal, we update and substantially expand our effort to periodically summarize the current body of information about schizophrenia. We compile a body of seventy-seven representative major findings and group them in terms of their specific relevance to schizophrenia -- etiologies, pathophysiology, clinical manifestations, and treatments. We rate each such "fact" on a 0-3 scale for measures of reproducibility, whether primary to schizophrenia, and durability over time. We also pose one or more critical questions with reference to each "fact", answers to which might help better elucidate the meaning of that finding for our understanding of schizophrenia. We intend to follow this paper with the submission to the journal of a series of topic-specific articles, critically reviewing the evidence.

Ontological assumptions of psychiatric taxonomy: main rival positions and their critical assessment

The scientific classification of human psychopathology raises a host of important philosophical issues ranging over all major areas of philosophical inquiry; logic, semantics, ontology, epistemology and ethics. The paper focuses on the major views of the ontological status of our psychodiagnostic constructs; idealism, nominalism and finally, neoaristotelian realism. Idealism holds that our psychodiagnostic constructs represent ideal essences, instantiated imperfectly by individual mental patients of the same psychodiagnostic class. These ideal essences are construed either as abstract forms dwelling in an autonomous realm of eternal abstract objects--platonistic idealism--or as ideal objects emerging in and grasped directly by a pure or absolute consciousness--husserlian idealism. By contrast, nominalism claims that our psychodiagnostic constructs are nothing but conventional common names of sets of individual mental patients, invented and adopted on purely pragmatic grounds such as their practical utility, especially in predicting their clinical course and outcome under various types of treatment. Finally, neoaristotelian realism holds that, though our psychodiagnostic constructs are concepts, and thus of our own making, they are not arbitrary ones but grounded in objective features shared by individual mental patients of a given psychodiagnostic class. It is argued that both idealism and nominalism are flawed and thus untenable--though for different reasons--and a refined version of neoaristotelian realism defended.