From a forensic perspective, the 2001 paper by Senior and Douglas on misconceptions and misuse of the MMPI-2 in assessing personal injury claimants signals the most important project concerning the MMPI-2 to appear since the new version was published in 1989. Based on a detailed analysis of protocols from 2441 forensic cases from Brisbane, Australia, Senior and Douglas argue that the traditional approach to MMPI-2 interpretation can not be empirically supported in the forensic context. They are particularly critical of code type interpretations and the use of the MMPI-2 as a basis for diagnostic decisions. Numerous previous researchers have raised important questions about the use of the MMPI-2 (e.g., see [3, 4,6,8,9,14]. However, none have addressed the questions in this paper with such a sizeable sample and in such detail, or applied such findings to the forensic neuropsychology context with such forceful and persuasive arguments. The implications of Senior and Douglas’s paper and the larger project of which it is a part affect several dimensions of forensic work at fundamental levels. Three overlapping aspects of differential diagnosis illustrate these problems. These are (1) identification of the most likely diagnosis, (2) ruling out psychological confounders of cognitive measures, and (3) the impact of a sensational weak link on the apparent reliability and validity of our test batteries. Differential diagnosis, although based on DSM criteria (DSM-IV as of this writing [1]), is routinely affected by test findings because test results affect the judgment of diagnosticians. For example, even if the patient’s self report is not completely consistent with the DSM criteria, it would be an unusual clinician who completely ignored powerful test evidence that appears to be valid. Because the MMPI-2 is more widely used than any other test for the psychological aspects of our diagnoses, as distinct from the cognitive measures associated with brain injury, it may have more effect than any other psychological test [7,10]. Ruling out confounders is a routine and essential component of forensic neuropsychological evaluations in which the expert addresses questions of causation, which includes the majority of forensic cases. It is commonplace in forensic neuropsychological reports to find expressions of concern about psychological or functional influences on our cognitive findings, e.g., depression, anxiety, or malingering. But if the potential confounder is illusory, we may not give full credence to valid results. Finally, in forensic neuropsychology we are subject to challenges over the scientific validity and reliability of our work not only in scientific forums but also in courts. For example, in the United States, the Daubert case and its progeny have inspired scientific challenges to expert methodology in Federal Court and many state courts (Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S.Ct. 2786 (1993)). Some courts have noted that a chain of scientific reasoning is only as strong as its weakest link. At times this is completely appropriate; at other times, an expert may make an error formulating one conclusion without undermining other conclusions. However, courts and experts may react with skepticism toward the rest of an assessment if one important component is seriously flawed. This skepticism at times may be cosmetic in nature, i.e., the speculative and overly broad assumption that an expert who makes one important error cannot be trusted to do anything right, but it may have serious effects on the credibility of the expert’s conclusions in general.
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Oct 13, 2020
Graziella Orrù + 5
Open Access
