Exploring the relationship between self-report and performance-based measures of impulsivity

Objective: Evaluations for attention-deficit/hyperactivity disorder (ADHD) in adulthood typically incorporate both self-report questionnaires and performance-based cognitive testing. Extant research has demonstrated weak or absent relationships between self-report and performance-based measures assessing the same or similar behavioral dimensions of ADHD (e.g., attention, planning); however, this dissociation remains understudied for impulsivity. This study examined the relationship between self-report and performance-based impulsivity measures in adults undergoing ADHD evaluation. Method: A clinical sample of 283 adults referred for ADHD evaluation completed the Minnesota Multiphasic Personality Inventory-3 Impulsivity scale (MMPI-3 IMP), Clinical Assessment of Attention Deficit-Adult (CAT-A), and Conners Continuous Performance Test-Third Edition (CPT-3). Regression analyses and correlational methods examined relationships between self-report and performance-based impulsivity measures. Results: MMPI-3 IMP scores did not significantly predict CPT-3 impulsivity variables. Logistic regressions demonstrated that MMPI-3 IMP scores had 83.6% classification accuracy in predicting normal vs. abnormal impulsivity performance but did not significantly predict elevated CPT-3 impulsivity. Parallel CAT-A analyses essentially mirrored MMPI-3 IMP findings. MMPI-3 IMP scores and CAT-A current and childhood impulsivity scores were moderately correlated, with significant concordance between MMPI-3 IMP and CAT-A current and childhood impulsivity scale elevations. Conclusion: Present findings align with prior literature indicating the MMPI-3 Impulsivity scale may not adequately capture and behavioral impulsivity measured by the CPT-3. Dissociation between MMPI-3 IMP and CPT-3 performance, coupled with convergence among self-report measures, indicates these modalities capture distinct aspects: subjective behavioral tendencies versus objective inhibitory control. Findings reinforce the need for multimodal ADHD assessment approaches.