Can we define mental disorder by using the criterion of mental dysfunction?

The concept of mental disorder is often defined by reference to the notion of mental dysfunction, which is in line with how the concept of disease in somatic medicine is often defined. However, the notions of mental function and dysfunction seem to suffer from some problems that do not affect models of physiological function. Functions in general have a teleological structure; they are effects of traits that are supposed to have a particular purpose, such that, for example, the heart serves the goal of pumping blood. But can we single out mental functions in the same way? Can we identify mental functions scientifically, for instance, by applying evolutionary theory? Or are models of mental functions necessarily value-laden? I want to identify several philosophical problems regarding the notion of mental function and dysfunction and point out some possible solutions. As long as these questions remain unanswered, definitions of mental disorder that rest upon the concept of mental dysfunction will lack a secure foundation.     

Dysfunction as a factual component of disorder

The harmful dysfunction (HD) analysis holds that disorder, mental or physical, requires harm, a value criterion, and dysfunction, a factual criterion referring to failure of a mechanism to perform a naturally selected function. Houts' arguments that the HD analysis does not offer an adequate factual account of dysfunction are examined and shown to be invalid. For example, his claim that the HD analysis confuses function with purpose, a value concept, ignores the analysis'account of function in terms of the value-free notion of effect-explanation; and his argument that functions imply norms (e.g., what mechanisms are 'supposed to' do) falsely assumes that such norms are evaluative. The HD analysis of function is analogous in logical structure to the functional analyst's factual behavioral notion of function. Houts' value account of disorder is inconsistent with people's classificatory judgments, as his own examples demonstrate.     

Evolutionary history versus current causal role in the definition of disorder: reply to McNally

The harmful dysfunction (HD) analysis (Wakefield, American Psychologist 47 (1992a) 373) asserts that "disorder" means "harmful dysfunction", where "harm" is a value concept anchored in social values and "dysfunction" is a factual concept referring to failure of a mechanism to perform a natural function. Additionally, the HD analysis claims that a mechanism's natural functions are its naturally selected effects. McNally (Behaviour Research and Therapy (2000) pp. 309-314) argues to the contrary that "dysfunction" is a value concept referring to negative failures of function, that "function" refers to current causal roles and not evolutionarily designed causal roles, and that "disorder" consequently means "harmful failure of a mechanism to perform a valued current causal role." I reply by showing that McNally's proposals lack the HD analysis's power to explain common judgments about function, dysfunction, and disorder. "Dysfunction" cannot be a negative value concept because many dysfunctions are positive or neutral; "function" cannot refer to current causal roles because many current causal roles are not functions and some functions are not current causal roles; and "disorder" cannot refer to harmful failures of current causal roles because that definition allows almost any negative condition whatever to be a disorder and thus fails to explain the distinctions we make between disorder and non-disorder.     

The concept of mental disorder. On the boundary between biological facts and social values.

Although the concept of mental disorder is fundamental to theory and practice in the mental health field, no agreed on and adequate analysis of this concept currently exists. I argue that a disorder is a harmful dysfunction, wherein harmful is a value term based on social norms, and dysfunction is a scientific term referring to the failure of a mental mechanism to perform a natural function for which it was designed by evolution. Thus, the concept of disorder combines value and scientific components. Six other accounts of disorder are evaluated, including the skeptical antipsychiatric view, the value approach, disorder as whatever professionals treat, two scientific approaches (statistical deviance and biological disadvantage), and the operational definition of disorder as "unexpectable distress or disability" in the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1987). The harmful dysfunction analysis is shown to avoid the problems while preserving the insights of these other approaches.     

Harmful dysfunction and the search for value neutrality in the definition of mental disorder: response to Wakefield, part 2

Wakefield's claims to have identified and objective scientific component of mental disorders in the concept of dysfunction are examined in light of previous attempts to state a value free concept of mental disorders. The harmful dysfunction concept of dysfunction is not value free because it confounds cause and purpose in a specious use of evolutionary theory and because evolutionary theory cannot reliably supply standards for when a function is broken. Harmful dysfunction analysis collapses into a value-laden concept of mental disorders and serves the untoward goal of promoting the status quo in the modern DSMs. If the concept of dysfunction were taken seriously and rigorously defined, then it might be possible to separate what is medical from what is not in the domain of mental disorders.     

The abduction of disorder in psychiatry.

The evolutionary cornerstone of J. C. Wakefield's (1999) harmful dysfunction thesis is a faulty assumption of comparability between mental and biological processes that overlooks the unique plasticity and openness of the brain's functioning design. This omission leads Wakefield to an idealized concept of natural mental functions, illusory interpretations of mental disorders as harmful dysfunctions, and exaggerated claims for the validity of his explanatory and stipulative proposals. The authors argue that there are numerous ways in which evolutionarily intact mental and psychological processes, combined with striking discontinuities within and between evolutionary and contemporary social/cultural environments, may cause nondysfunction variants of many widely accepted major mental disorders. These examples undermine many of Wakefield's arguments for adopting a harmful dysfunction concept of mental disorder.     

Problems in the Definition of 'Mental Disorder'

Current diagnostic manuals in psychiatry such as DSM and ICD offer definitions of mental disorder, though it is recognized that they are unsatisfactory. It is likely that philosophy can help in this problem of definition. I argue that philosophical theories of mind have always implied definitions of mental disorder. Contemporary theories of mind commonly take intentionality to be fundamental, and I consider to what extent mental disorder can be defined in terms of radical failures of intentionality. Dennett has suggested that breakdown of intentional systems is to be explained from the physical stance, but explanations of breakdown from the design stance and even from the intentional stance are possible. Evolutionary theory emphasizes the intentionality of mind and behaviour, and is increasingly applied in models of psychopathology. It is unlikely that these models support the concept of mental disorder at work in current psychiatry.     

Mental disorder as a black box essentialist concept.

This is a reply to commentaries on the target article (J. C. Wakefield, 1999) on the evolutionary foundations of the concept of mental disorder in defense of the harmful dysfunction analysis (HDA) of disorder. The author argues that the HDA is adequate to explain disorder and nondisorder judgments and is not disconfirmed by any of the claimed counterexamples put forward by the commentators; the commentators' proposed alternatives to the HDA are inadequate to explain disorder and nondisorder judgments; and the concept of natural function is a factual, scientific concept, contrary to K. W. M. Fulford's (1999) claim that it is inherently evaluative. The foundations of the HDA are clarified by providing a black box essentialist analysis (H. Putnam, 1975; J. C. Wakefield, 1997, in press) of the concept of natural function that underlies the concept of disorder.     

Where’s the problem? Considering Laing and Esterson’s account of schizophrenia,social models of disability,and extended mental disorder

In this article, I compare and evaluate R. D. Laing and A. Esterson’s account of schizophrenia as developed in Sanity, Madness and the Family (1964), social models of disability, and accounts of extended mental disorder. These accounts claim that some putative disorders (schizophrenia, disability, certain mental disorders) should not be thought of as reflecting biological or psychological dysfunction within the afflicted individual, but instead as external problems (to be located in the family, or in the material and social environment). In this article, I consider the grounds on which such claims might be supported. I argue that problems should not be located within an individual putative patient in cases where there is some acceptable test environment in which there is no problem. A number of cases where such an argument can show that there is no internal disorder are discussed. I argue, however, that Laing and Esterson’s argument—that schizophrenia is not within diagnosed patients—does not work. The problem with their argument is that they fail to show that the diagnosed women in their study function adequately in any environment.     

Harm and the concept of medical disorder

According to Jerome Wakefield’s harmful dysfunction analysis (HDA) of medical disorder, the inability of some internal part or mechanism to perform its natural function is necessary, but not sufficient, for disorder. HDA also requires that the part dysfunction be harmful to the individual. I consider several problems for HDA’s harm criterion in this article. Other accounts on which harm is necessary for disorder will suffer from all or almost all of these problems. Comparative accounts of harm imply that one is harmed when one is made worse off, that is, worse off than one otherwise would have been. Non-comparative accounts imply that one is harmed when one is put into some kind of condition or state that is, in some way, bad in itself. I argue that whether harm is construed comparatively or non-comparatively, HDA’s harm criterion is problematic. I tentatively conclude that an analysis of medical disorder should not make use of the concept of harm.     

Resolving the paradox of common, harmful, heritable mental disorders: which evolutionary genetic models work best?

Given that natural selection is so powerful at optimizing complex adaptations, why does it seem unable to eliminate genes (susceptibility alleles) that predispose to common, harmful, heritable mental disorders, such as schizophrenia or bipolar disorder? We assess three leading explanations for this apparent paradox from evolutionary genetic theory: (1) ancestral neutrality (susceptibility alleles were not harmful among ancestors), (2) balancing selection (susceptibility alleles sometimes increased fitness), and (3) polygenic mutation-selection balance (mental disorders reflect the inevitable mutational load on the thousands of genes underlying human behavior). The first two explanations are commonly assumed in psychiatric genetics and Darwinian psychiatry, while mutation-selection has often been discounted. All three models can explain persistent genetic variance in some traits under some conditions, but the first two have serious problems in explaining human mental disorders. Ancestral neutrality fails to explain low mental disorder frequencies and requires implausibly small selection coefficients against mental disorders given the data on the reproductive costs and impairment of mental disorders. Balancing selection (including spatio-temporal variation in selection, heterozygote advantage, antagonistic pleiotropy, and frequency-dependent selection) tends to favor environmentally contingent adaptations (which would show no heritability) or high-frequency alleles (which psychiatric genetics would have already found). Only polygenic mutation-selection balance seems consistent with the data on mental disorder prevalence rates, fitness costs, the likely rarity of susceptibility alleles, and the increased risks of mental disorders with brain trauma, inbreeding, and paternal age. This evolutionary genetic framework for mental disorders has wide-ranging implications for psychology, psychiatry, behavior genetics, molecular genetics, and evolutionary approaches to studying human behavior.     

Defining mental disorder. Exploring the 'natural function' approach

Due to several socio-political factors, to many psychiatrists only a strictly objective definition of mental disorder, free of value components, seems really acceptable. In this paper, I will explore a variant of such an objectivist approach to defining metal disorder, natural function objectivism. Proponents of this approach make recourse to the notion of natural function in order to reach a value-free definition of mental disorder. The exploration of Christopher Boorse's 'biostatistical' account of natural function (1) will be followed an investigation of the 'hybrid naturalism' approach to natural functions by Jerome Wakefield (2). In the third part, I will explore two proposals that call into question the whole attempt to define mental disorder (3). I will conclude that while 'natural function objectivism' accounts fail to provide the backdrop for a reliable definition of mental disorder, there is no compelling reason to conclude that a definition cannot be achieved.     

Moral Responsibility, Psychiatric Disorders and Duress

ABSTRACT  The paper is a discussion of moral responsibility and excuses in regard to psychiatric disorders involving abnormal desires (e.g. impulse control disorders such as kleptomania and pyromania, psychosexual disorders such as exhibitionism, obsessive-compulsive disorder and others). It points out problems with previous approaches to the question of whether or not to excuse persons with these disorders, and offers a new approach based on the concept of duress. There is a discussion of duress in regard to non-psychiatric cases based on the core notion of duress involving a choice between undesirables, and the paper concludes with an argument that moral blame for individuals with these sorts of disorders should often be lessened and in some cases removed entirely.     

The felt presence of other minds: Predictive processing,counterfactual predictions,and mentalising in autism

The mental states of other people are components of the external world that modulate the activity of our sensory epithelia. Recent probabilistic frameworks that cast perception as unconscious inference on the external causes of sensory input can thus be expanded to enfold the brain’s representation of others’ mental states. This paper examines this subject in the context of the debate concerning the extent to which we have perceptual awareness of other minds. In particular, we suggest that the notion of perceptual presence helps to refine this debate: are others’ mental states experienced as veridical qualities of the perceptual world around us? This experiential aspect of social cognition may be central to conditions such as autism spectrum disorder, where representations of others’ mental states seem to be selectively compromised. Importantly, recent work ties perceptual presence to the counterfactual predictions of hierarchical generative models that are suggested to perform unconscious inference in the brain. This enables a characterisation of mental state representations in terms of their associated counterfactual predictions, allowing a distinction between spontaneous and explicit forms of mentalising within the framework of predictive processing. This leads to a hypothesis that social cognition in autism spectrum disorder is characterised by a diminished set of counterfactual predictions and the reduced perceptual presence of others’ mental states.     

How do we know that we are unique?

This paper aims to examine the notion of uniqueness as one aspect of the self that is taken for granted in psychotherapy. This paper attempts to address the question 'how do we know that we are unique individuals?' and in so doing, points out some difficulties. One plausible, but not problem-free answer is the notion of privileged access. Some of the problems will be briefly outlined.     

Mental models in the brain: On context-dependent neural correlates of mental models

In this paper, the concept of context-dependent realisation of mental models is introduced and discussed. Literature from neuroscience is discussed showing that different types of mental models can use different types of brain areas. Moreover, it is discussed that the same occurs for the formation and adaptation of mental models and the control of these processes. This makes that it is hard to claim that all mental models use the same brain mechanisms and areas. Instead, the notion of context-dependent realisation is proposed here as a better manner to relate neural correlates to mental models. It is shown in some formal detail how this context-dependent realisation approach can be related to well-known perspectives based on bridge principle realisation and interpretation mapping realisation.     

Propositional reasoning: the differential contribution of "rules" to the difficulty of complex reasoning problems

In Experiment 1, complex propositional reasoning problems were constructed as a combination of several types of logical inferences: modus ponens, modus tollens, disjunctive modus ponens, disjunctive syllogism, and conjunction. Rule theories of propositional reasoning can account for how one combines these inferences, but the difficulty of the problems can be accounted for only if a differential psychological cost is allowed for different basic rules. Experiment 2 ruled out some alternative explanations for these differences that did not refer to the intrinsic difficulty of the basic rules. It was also found that part of the results could be accounted for by the notion of representational cost, as it is used in the mental model theory of propositional reasoning. However, the number of models as a measure of representational cost seems to be too coarsely defined to capture all of the observed effects.     

Toward computational neuroconstructivism: a framework for developmental systems neuroscience

Brain development is underpinned by complex interactions between neural assemblies, driving structural and functional change. This neuroconstructivism (the notion that neural functions are shaped by these interactions) is core to some developmental theories. However, due to their complexity, understanding underlying developmental mechanisms is challenging. Elsewhere in neurobiology, a computational revolution has shown that mathematical models of hidden biological mechanisms can bridge observations with theory building. Can we build a similar computational framework yielding mechanistic insights for brain development? Here, we outline the conceptual and technical challenges of addressing this theory gap, and demonstrate that there is great potential in specifying brain development as mathematically defined processes operating within physical constraints. We provide examples, alongside broader ingredients needed, as the field explores computational explanations of system-wide development.