What Is Mental Illness? (Belknap Press, 2011) opens with a set of claims which seem to suggest that the Western world is facing an 'epidemic of madness.' Richard McNally challenges the reader to come to terms with the following facts:
· Nearly 50 percent of Americans have been mentally ill at some point in their lives (1);
· Americans seem more vulnerable to breakdown than people in less fortunate regions of the globe (1);
· The typical student in the 1990s would have looked neurotic in the 1950s (6);
· Since 1970s, psychiatry discovered 327 new forms of mental illness (27).
These claims, however, are not meant to alarm the reader and to have her infer that there is an 'epidemic of madness' in America. Rather, McNally uses these claims to raise the question concerning the diagnostic legitimacy in the realm of mental illness. As he puts it: "when epidemiologists announce that half of America has suffered from mental illness, they're playing by the rules," in that this diagnosis is consistent with the current edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM); "the problem, however, is that the rules themselves may be faulty" (4). What Is Mental Illness? seeks to explore the boundary between mental disorder (or illness) and metal distress. In doing this, McNally offers a "friendly criticism" and "constructive suggestions" for the revision of the current edition of the DSM. As the fifth and the most recent edition of DSM is being prepared to appear in 2013, McNally offers particular remedies for some of the principal drawbacks in diagnostics from which the former DSM editions suffered.
McNally situates his argument in the context of discussing the theoretical approach endorsed by the DSM-III. The DSM-III (1980) contained a "revolutionary" break with the psychoanalytic past (203). This revolution consisted mainly in adopting a descriptive approach to diagnostics – the approach that was meant to be "unburdened of empirically unsubstantiated theoretical assumptions" (ibid.). In particular, the DSM-III approached mental illness through "operational definitions," i.e., it defined mental illnesses through their signs and symptoms. McNally points out that the commitment to "operationalism" was not itself a theoretical one; rather, it betrayed the need for a genuinely empirical approach to mental disorders, an approach that scientists with diverse theoretical commitments could embrace. While operationalism was able to satisfy this need, it opened the door to another problem: if a mental illness is defined in terms of its symptoms, then the diagnosis seems to be blind to the etiology or the causal story of mental disorders. In other words, the descriptive appeal to signs and symptoms alone leaves out the etiology that we commonly consider to be crucial in other areas of medicine.
One implication of the operational approach adopted by the DSM-III (and largely preserved by the DSM-IV (1994)) is the "boundary problem," i.e., the problem of distinguishing disorder from distress (64). Unless we are able to specify the cause of a particular set of symptoms, it is often undetermined whether the symptoms amount to a disorder (e.g., clinical depression), or whether they constitute a non-disordered response to the events in patient's life (e.g., mourning the loss of a loved one). What Is Mental Illness? is largely dedicated to reviewing currently available etiological answers that are called for in augmenting the descriptive approach and that compete for solving the 'boundary problem.' Chapters 3, 4, 5, and 6 provide an overview of such attempts: in chapter 3, McNally discusses the strengths and weaknesses of the harmful dysfunction analysis (HDA) which holds that mental disorders are "dysfunctions in [our] evolved psychobiological mechanisms" (96); chapter 4 surveys the 'psychopathology as adaptation' theory according to which disorders themselves are evolved adaptations. Thus, chapters 3 and 4 discuss the evolutionary approaches to psychopathology – approaches that see evolution as the appropriate causal mechanism for explaining and classifying mental illness. Later, in chapter 5, McNally discusses the social construction theory of mental illness (or at least of a subset of mental disorders), according to which (some) mental disorders are not "stable, ahistorical entities whose essence is invariant irrespective of cultural variation," but that they are socially constructed instead (130). And in chapter 6, McNally considers the role that molecular genetics and neuroscience might play in our shift from the descriptive approach of DSM-III and –IV and toward an etiological view that DSM-V will strive to incorporate.
McNally's analysis of one of the tracks in evolutionary psychology in chapter 3 ('Can Evolutionary Psychology Make Sense of Mental Disorder?') can serve as a good example of commitment to provide helpful guidance to the etiological turn of DSM-V. The departing point of McNally's analysis is the work of Jerome Wakefield and specifically, the concept of harmful dysfunction analysis (HDA) that Wakefield developed in the 1990s. According to the HDA, "a disorder exists when the failure of a person's internal mechanisms to perform their functions as designed by nature impinges harmfully on the person's well-being as defined by social values and meanings" (70-1). McNally points out that this approach has two components: it is both (i) factual (in so far as it addresses evolved psychological mechanisms) and (ii) normative (in so far as it relies on the notion of harm), although he acknowledges that the factual component involves some appeal to value-concepts since evolutionary theory itself is value-laden (71). McNally then goes on to discuss both (i) and (ii) and to suggest a significant revision of Wakefield's original HDA approach. With respect to the factual component, McNally's analysis raises a set of important questions. For instance, while Wakefield's analysis relies on understanding of evolved psychological mechanisms as historical adaptations, it is far from clear that they are adaptations rather then exaptations (features that evolved for one function and then acquires additional functions). For instance, mechanisms that are responsible for reading, writing, capacity to compose music, etc. might be exaptations since they evolved for purposes other than the ones for which we currently use them (83). If this is the case, then HDA would exclude large set of disorders, since HDA defines disorders as harmful dysfunctions in adaptations (and not in exaptations). This points to a more general problem with HDA's reliance on an evolutionary history rather than on the causal role the mechanisms have within our nervous system (86). According to McNally, this is one of the most significant revisions that HDA needs to accommodate – it should "replace the evolutionary concept of function with the current causal role concept of function" (94). If we turn to the second component of HDA – the harmfulness of the dysfunction – we see that refinement is warranted here as well. Examples of pedophilia and homosexuality illustrate this point well: "pedophiles [usually] experience no distress about their deviation" (and thus pedophilia would not be classified as a dysfunction according to HDA), whereas in a homophobic society homosexuals may experience a great deal of harmful distress (which would make homosexuality a disorder according to HDA). This means that the concept of harm ought to be developed further to do justice to the complexity of this phenomenon (88-9).
McNally acknowledges that the boundary between a mental disorder and mental distress will remain "fuzzy." He says that we will "never get a clear-cut list of criteria that will enable us to identify all instances of mental disorder and exclude everything else" (212). What Is Mental Illness? shows, however, that the boundary problem is not merely a practical one, and that its roots are philosophical. One inherent complexity in the classification of disorders has to do with conceptual pluralism, which is now commonly accepted in philosophy of science. For instance, "there might be no single, correct way of categorizing the biological world suitable for all purposes. Although geneticists, evolutionists, ecologists, and physiologists all seek to describe and explain the features of the living world, their questions are so different and their aims so diverse that it seems unlikely that a single concept of species will fit their diverse aims" (208). If we can be pluralists with respect to the concept of a species, we might be equally inclined to be pluralists with respect to the concept of a disorder. This does not imply conceptual 'anarchy'; rather, it suggests that "given a specific domain or question, there will be one way of fixing the taxonomy" (ibid.). Furthermore, even within a given taxonomical system, there might be at best only a family resemblance between various types of disorders. This, again, should not strike us as unusual in the wake of Wittgenstein's work on conceptual relations (212).
What Is Mental Illness? is bound to interest anyone who wants to understand the theoretical path from psychoanalysis to DSM-III and DSM-IV with their emphasis on signs and symptoms, and with their commitment to operationalism. McNally argues powerfully to the conclusion that the operationalism (albeit a necessary approach in the 1980s) now ought to be replaced by an etiologically and psycho-physiologically informed accounts of dysfunction, and in this his account is bound to be a welcome piece of theoretical advice in preparation of DSM-V (2013). Furthermore, What Is Mental Illness? is a valuable read for the student of philosophy of science in general, since it contains numerous insights on theoretical questions with respect to taxonomy, functional analysis, conceptual pluralism, etc. important in contemporary discussions of philosophy of science. Finally (and more specifically), the book provides both a subtle methodological approach for and a complex substantive answer to the question -- What is mental illness?
© 2011 Tatiana Patrone
Tatiana Patrone, Ph.D., Department of Philosophy and Religion, Ithaca College