Misuse of Cognitive Neuropsychology in Psychiatry Research : The Intoxicating Appeal of Neo-Reductionism

187 NEUROPSYCHOLOGICAL DIAGNOSTIC instruments were developed expressly for the detection of and assessment of neurological disorders (e.g., Lezak, Howieson, Bigler, &Tranel, 2012). The historic role of these instruments in locating damage in the central nervous system has diminished with the advent of various imaging technologies. Thus, the prominent role of neuropsychological assessment has been circumscribed predominantly to determining the extent of cognitive, emotional, and behavioral dysfunctions subsequent to brain damage. Nowadays, cognitive neuropsychology, the study of cognitive functioning, is being clinically utilized to demonstrate disability in educational, medical, and forensic settings, and increasingly utilized in psychiatry research. For example, a recent systematic review of neuropsychological investigations into obsessive-compulsive disorder (OCD) noted a fourfold increase in the number of peer-reviewed publications between the years 1990–2000, compared with 2000– 2010 (Abramovitch, Dar, Mittelman, & Schweiger, 2013) The age of the brain invigorated the biomedical model of psychological problems, and virtually transformed psychiatry to a new science that would be more appropriately titled “biological psychiatry” (Guze, 1989). To a considerable extent, this transformation essentiallymedicalized psychology as well, both in terms of its explanatory models and the search for remediation of psychopathology. Cerebral pathology has begun to take center stage as the primary focus in research on etiology of psychopathology, which is being now conceptualized as the expression of aberrations in brain functions, or “brain disease” (Deacon, 2013). The utilization of the best standardized objective behavioral approach to measure brain pathology, namely, neuropsychological testing, was the logical next step in the arsenal of identifying such diseases. Although neuropsychological tests are sensitive to behavioral dysfunction, they are inherently nonspecific. For example, a test sensitive to a decline in visual spatial skills cannot distinguish whether this decline is due to brain pathology, peripheral perceptual deficit, or motivationaland effort-related factors on the part of the examinee. As such, neuropsychological tests can speak to the relative difference from normative functioning, thus providing a very useful tool, but not one that speaks directly to the etiology of the deficit. Consequently, the potential for neuropsychological test results of one kind or another to serve as an endophenotypical factor or “cognitive marker” in psychopathology is extremely limited (Caspi et al., 2013). It’s no wonder, therefore, that despite years of well-funded research, not a single biological or cognitive marker, or a cluster of markers, have been identified that would predict a specific psychopathology. It is not even clear that a search for such etiological factors could yield theoretically useful fruits. The ongoing discontent with the DSM classification system, together with the increasing appeal of neuroscience, and the trend toward a more reductionist, biologically based (preferably brain-related) approach to psychiatric disorders, engendered the NIMH RDoC initiative (Lilienfeld, 2014). The RDoC vision emerges from the assumption that “psychiatric disorders” are brain disorders and, as such, could be one day fully explained and treated by unraveling their underlying brain abnormalities. Indeed, the RDoC envisions a time when a patient would come into a clinic, have his/her brain scanned (and may undergo a saliva test or take a few brief cognitive tests), the results of which would indicate whether or not this person presents with the biomarkers that fit into one or another category of pathology (e.g., negative affect). Once identified, the subsequent treatment for such a disorder would be the appropriate biologically based agents, or neurotherapy such as deep brain stimulation (DBS). The work of the RDoC “Unit Work Groups” produced a detailed matrix to be used as a guideline for researchers. This matrix includes specific domains for future research (e.g., positive Valence System, Cognitive Systems), specific constructs (e.g., Reward Learning, and Frustrative Non reward) to be examined using specific units of analysis (e.g., genes, neuronal circuits, molecules, or behavior). Recent criticism regarding this vision has been leveled concerning different aspects of this approach, including the problems underlying the assumption that psychological conditions are brain disorders associated with a state of chemical imbalance (Lacasse & Leo, 2015), and the difficulties of a narrow, reductionist explanation of psychological entities (Satel & Lilienfeld, 2015) analogous to the attempt to explain “wetness” by referring exclusively toH2Omolecules. Criticismwas also directed at the return to a modern version of phrenology (e.g., the relentless attempt to circumscribe psychological phenomena to highly specific brain regions or neuronal networks), sometimes referred to as neophrenology (Satel & Lilienfeld). However, in this article we focus on a specific domain within the RDoC initiative, namely, the domain of cognitive neuropsychology and neuropsychological tests in the context of psychiatry research. This domain, with its allure of objectivity, has been utilized in psychiatry research for a few decades. Recently it becomes increasingly evident that cognitive neuropsychology has been recruited to serve the premises of biological psychiatry, in a similar way to brain imaging.