Further Validation of the Conner's Adult Attention Deficit/Hyperactivity Rating Scale Infrequency Index (CII) for Detection of Non-Credible Report of Attention Deficit/Hyperactivity Disorder Symptoms

Objective. Attention deficit/hyperactivity disorder (ADHD) can be easily presented in a non-credible manner, through non-credible report of ADHD symptoms and/or by non-credible performance on neuropsychological tests. While most studies have focused on detection of non-credible performance using performance validity tests, there are few studies examining the ability to detect non-credible report of ADHD symptoms. We provide further validation data for a recently developed measure of non-credible ADHD symptom report, the Conner's Adult ADHD Rating Scales (CAARS) Infrequency Index (CII). Method. Using archival data from 86 adults referred for concerns about ADHD, we examined the accuracy of the CII in detecting extreme scores on the CAARS and invalid reporting on validity indices of the Minnesota Multiphasic Personality Inventory-2 Restructured Format (MMPI-2-RF). We also examined the accuracy of the CII in detecting non-credible performance on standalone and embedded performance validity tests. Results. The CII was 52% sensitive to extreme scores on CAARS DSM symptom subscales (with 97% specificity) and 20%-36% sensitive to invalid responding on MMPI-2-RF validity scales (with near 90% specificity), providing further evidence for the interpretation of the CII as an indicator of non-credible ADHD symptom report. However, the CII detected only 18% of individuals who failed a standalone performance validity test (Word Memory Test), with 87.8% specificity, and was not accurate in detecting non-credible performance using embedded digit span cutoffs. Conclusions. Future studies should continue to examine how best to assess for non-credible symptom report in ADHD referrals.