Objective: Two studies examined the psychometric properties of the Multidimensional ADHD Rating Scale (MARS), which assesses ADHD symptoms, related functional impairment, and symptom validity (SV). Method: Study 1 used MARS item responses from college students with and without ADHD (with some of the latter group assigned to feign ADHD) to create an SV-index, and to identify optimal cut scores for the clinical (symptom and impairment) indexes. Study 2 cross-validated the findings on a new sample. Results: In both studies, malingerers reported more symptoms and impairment than participants with ADHD, who reported more symptoms and impairment than controls. Receiver operating characteristic analyses found very good discrimination of genuine ADHD from control cases by the clinical MARS indexes, and very good discrimination of genuine ADHD from malingered ADHD by the SV-index. Conclusion: This research provides initial support for the effectiveness of the MARS to detect simulated cases of malingering, and to differentiate ADHD from non-ADHD cases in college students.
Keywords: ADHD; assessment; impairment; malingering; symptom validity.