Slick, D.J., & Sherman, E.M.S. (in press). Differential diagnosis of malingering and related clinical presentations. In E.M.S. Sherman and B.L. Brooks (Eds.), Pediatric Forensic Neuropsychology. New York: Oxford University Press. Chapter 7 Differential Diagnosis of Malingering and Related Clinical Presentations Daniel J. Slick and Elisabeth M.S. Sherman Every year in North America, thousands of litigating or otherwise compensation seeking children, adolescents and adults undergo third-party neuropsychological assessments. Among the adults in this population, malingering is far from rare; survey data indicate that 20%–40% of compensation-seeking adults are thought to be feigning some type of neuropsychological problem or impairment (Mittenberg, Patton, Canyock & Condit, 2002; Sharland, & Gfeller, 2007; Slick, Tan, Strauss, & Hultsch, 2004). Although the rate of malingering among minors is almost certainly non-trivial as well, no good estimates are currently available – an indication of the general dearth of research on pediatric malingering. Fortunately for clinicians, researchers have finally begun to focus in earnest on the problem of pediatric malingering and it now appears likely that the current void in our understanding of this phenomenon will have shrunken substantially by the end of this decade. This chapter addresses malingering and related clinical presentations in children and adolescents (i.e., minors), primarily in the context of independent neuropsychological assessment of compensation-seeking individuals. The focus is first on critical concepts, constructs and definitions; and then on differential diagnosis, with issues of neurocognitive and psychosocial development addressed where relevant. Specific psychometric tests and assessment methods are not discussed in any detail (for which see Kirkwood, chapter 7 this volume). Definition and Conceptual Aspects of Malingering The first papers on the forced-choice method for assessing the validity of sensory deficits appeared in major psychology journals in the 1970s (Pankratz, Fausti, and Peed, 1975; Pankratz, 1979). 1 During the following decade, neuropsychologists began to adapt the forced-choice method for use in evaluating the validity of cognitive complaints (Binder and Pankratz, 1987; Hiscock 1989). Prior to this, malingering was a relatively obscure subject of study within neuropsychology and not a phenomenon of interest or concern for many clinicians. However, these early studies helped catalyze an explosive growth in research on malingering that was driven in large part by the increasing involvement of neuropsychologists in forensic and medicolegal fields where the issue of malingering looms large. A significant problem faced by researchers and clinicians in the 1980s and 1990s was the lack of an adequate functional definition and associated diagnostic criteria for malingering. In an attempt to meet this need, a definition and detailed diagnostic criteria for malingering was developed by Slick, Sherman and Iverson (1999). They defined Malingered Neurocognitive Dysfunction (MND) as: the volitional exaggeration or fabrication of cognitive dysfunction for the purpose of obtaining substantial material gain, or avoiding or escaping formal duty or responsibility. Substantial material 1 Forced-choice symptom validity testing, though new psychology in the mid-1970s, was initially developed by physicians in the late 1950s for assessment of conversion disorder and malingering (e.g., Brady & Lind, 1961).