Comparison of Clinical Psychologist and Physician Beliefs and Practices Concerning Malingering: Results from a Mixed Methods Study

Review of Statistical and Methodological Issues in the Forensic Prediction of Malingering from Validity Tests: Part I: Statistical Issues

Forensic neuropsychological examinations with determination of malingering have tremendous social, legal, and economic consequences. Thousands of studies have been published aimed at developing and validating methods to diagnose malingering in forensic settings, based largely on approximately 50 validity tests, including embedded and stand-alone performance validity tests. This is the first part of a two-part review. Part I explores three statistical issues related to the validation of validity tests as predictors of malingering, including (a) the need to report a complete set of classification accuracy statistics, (b) how to detect and handle collinearity among validity tests, and (c) how to assess the classification accuracy of algorithms for aggregating information from multiple validity tests. In the Part II companion paper, three closely related research methodological issues will be examined. Statistical issues are explored through conceptual analysis, statistical simulations, and through reanalysis of findings from prior validation studies. Findings suggest extant neuropsychological validity tests are collinear and contribute redundant information to the prediction of malingering among forensic examinees. Findings further suggest that existing diagnostic algorithms may miss diagnostic accuracy targets under most realistic conditions. The review makes several recommendations to address these concerns, including (a) reporting of full confusion table statistics with 95% confidence intervals in diagnostic trials, (b) the use of logistic regression, and (c) adoption of the consensus model on the "transparent reporting of multivariate prediction models for individual prognosis or diagnosis" (TRIPOD) in the malingering literature.

Feigning Symptoms to Obtain Prescription Stimulants: A Vignette-Based Study on Its Conditions

This vignette-based study examined the willingness to feign symptoms to obtain a prescription following an analysis on who might use prescription stimulants to enhance performance ( N = 3,468). It experimentally manipulated three factors: the social disapproval of prescription stimulant use for enhancement purposes, the physicians’ diagnostic efforts, and the medical condition (attention-deficit/hyperactivity disorder and narcolepsy); respondent characteristics of self-control, personal morality, and self-efficacy were also measured. Our results showed that social disapproval of prescription drug use, a personal morality that disapproves of drug use, high self-control, and high self-efficacy were negatively associated with the willingness to use. Willingness increased especially in situations of social approval when there was a stronger personal approval of drug use, or surprisingly when physicians’ diagnostic efforts were higher. The feigning willingness was lower in situations of social disapproval and when personal morality disapproved of feigning. Thus, personal and situational characteristics are relevant to understand both behaviors.