Introduction: The Clinical Assessment of Attention Deficit-Adult is among the few questionnaires that offer validity indicators (i.e., Negative Impression [NI], Infrequency [IF], and Positive Impression [PI]) for classifying underreporting and overreporting of attention-deficit/hyperactivity disorder (ADHD) symptoms. This is the first study to cross-validate the NI, IF, and PI scales in a sample of adults with suspected or known ADHD.
Method: Univariate and multivariate analyses were conducted to examine the independent and combined value of the NI, IF, and PI scores in predicting invalid symptom reporting and neurocognitive performance in a sample of 543 adults undergoing ADHD evaluation.
Results: The NI scale demonstrated better classification accuracy than the IF scale in discriminating patients with and without valid scores on measures of overreporting. Only NI scores significantly predicted validity status when used in combination with IF scores. Optimal cut-scores for the NI (≤51; 30% sensitivity / 90% specificity) and IF (≥4; 18% sensitivity / 90% specificity) scales were consistent with those reported in the original manual; however, these indicators poorly discriminated patients with invalid and valid neurocognitive performance. The PI scale demonstrated acceptable classification accuracy in discriminating patients with invalid and valid scores on measures of underreporting, albeit with an optimal cut-score (≥27; 36% sensitivity / 90% specificity) lower than that described in the manual.
Conclusion: Findings provide preliminary evidence of construct validity for these scales as embedded validity indicators of symptom overreporting and underreporting. However, these scales should not be used to guide clinical judgment regarding the validity of neurocognitive test performance.
Keywords: ADHD; CAT-A; overreporting; symptom validity; underreporting.