Utility of the Personality Assessment Inventory in detecting feigned Attention-Deficit/Hyperactivity Disorder (ADHD): The Feigned Adult ADHD index

Objective: The high potential for secondary gain among college students presenting for Attention-Deficit/Hyperactivity Disorder (ADHD) evaluations highlights the need for psychometrically sound embedded validity indicators. The purpose of this study was to develop new validity indicators specific to feigned ADHD for the Personality Assessment Inventory (PAI) and compare them to preexisting imbedded PAI validity measures. Method: PAI scales that were theoretically related to feigned ADHD were evaluated. A binomial (ADHD simulators, n = 138, and genuine ADHD, n = 142) logistic regression was conducted with selected PAI scales and subscales. Classification rates were compared between the new and existing validity scales. A similar approach was used for item-level data in a second study in a subgroup of the original sample. Results: The derived PAI scale-based logistic regression had a sensitivity of 54% and specificity of 92%. This algorithm accurately identified 97% of healthy controls as not feigning ADHD and correctly identified 98% of a no diagnosis group and 75% of a mood/anxiety disorders group. Classification accuracy of the new index was superior to the majority of existing PAI validity scales across groups. An item-level PAI algorithm had a sensitivity of 85% and specificity of 97% for identifying feigned ADHD. Conclusions: New validity measures were compared to existing PAI validity indicators and performed better than many of them in this study. The algorithms developed in this study of ADHD simulators and genuine ADHD cases have adequate sensitivity and good specificity and appear to function differently than other PAI symptom validity scales.