Development of an Infrequency Index for the CAARS

There is a clinical need for measurement of noncredible self-reporting of symptoms of attention deficit hyperactivity disorder (ADHD) in adults presenting for ADHD evaluation. The present study describes the development of initial validity data for an Infrequency Index for the Conner’s Adult Attention Deficit/Hyperactivity Rating Scale (CII). Items for the CII were obtained from a large sample of nontreatment seeking university students, including individuals with a selfreported history of ADHD diagnosis. Items endorsed infrequently in the sample, including those with ADHD diagnoses, were identified and summed to create the CII. Initial validation data were gathered from a sample of individuals seeking clinical evaluation for ADHD. The CII was strongly related to noncredibly high symptom report and was also related to noncredible performance on cognitive measures. Results provide initial support for the CII’s use in assessing noncredible overreporting on the Conner’s Adult Attention-Deficit/Hyperactivity Rating Scale.