The Divergent Roles of Symptom and Performance Validity in the Assessment of ADHD

Exploring Subfactors of Adult Cognitive Disengagement Syndrome and Impact on Neuropsychological Performance

OBJECTIVE

This study investigated subfactors of cognitive disengagement syndrome (CDS; previously referred as sluggish cognitive tempo) among adults referred for neuropsychological evaluation of attentiondeficit/hyperactivity disorder (ADHD).

METHOD

Retrospective analyses of data from 164 outpatient neuropsychological evaluations examined associations between CDS subfactors and self-reported psychological symptoms and cognitive performance.

RESULTS

Factor analysis produced two distinct but positively correlated constructs: "Cognitive Complaints'' and "Lethargy." Both correlated positively with symptom reports (rs = 0.26-0.57). Cognitive Complaints correlated negatively with working memory, processing speed, and executive functioning performance (rs = -0.21 to -0.37), whereas Lethargy correlated negatively only with processing speed and executive functioning performance (rs = -0.26 to -0.42). Both predicted depression symptoms, but only Cognitive Complaints predicted inattention symptoms. Both subfactors demonstrated modest to nonsignificant associations with cognitive performance after accounting for estimated premorbid intelligence and inattention.

CONCLUSION

Findings indicate a bidimensional conceptualization of CDS, with differential associations between its constituent subfactors, reported symptoms, and cognitive performance.

Using the MMPI-2-RF, IOP-29, IOP-M, and FIT in the In-Person and Remote Administration Formats: A Simulation Study on Feigned mTBI

Our study compared the impact of administering Symptom Validity Tests (SVTs) and Performance Validity Tests (PVTs) in in-person versus remote formats and assessed different approaches to combining validity test results. Using the MMPI-2-RF, IOP-29, IOP-M, and FIT, we assessed 164 adults, with half instructed to feign mild traumatic brain injury (mTBI) and half to respond honestly. Within each subgroup, half completed the tests in person, and the other half completed them online via videoconferencing. Results from 2 ×2 analyses of variance showed no significant effects of administration format on SVT and PVT scores. When comparing feigners to controls, the MMPI-2-RF RBS exhibited the largest effect size (d = 3.05) among all examined measures. Accordingly, we conducted a series of two-step hierarchical logistic regression models by entering the MMPI-2-RF RBS first, followed by each other SVT and PVT individually. We found that the IOP-29 and IOP-M were the only measures that yielded incremental validity beyond the effects of the MMPI-2-RF RBS in predicting group membership. Taken together, these findings suggest that administering these SVTs and PVTs in-person or remotely yields similar results, and the combination of MMPI and IOP indexes might be particularly effective in identifying feigned mTBI.

Examination of the relationship between symptom and performance validity measures across referral subtypes

INTRODUCTION

The extent to which performance validity (PVT) and symptom validity (SVT) tests measure separate constructs is unclear. Prior research using the Minnesota Multiphasic Personality Inventory (MMPI-2 & RF) suggested that PVTs and SVTs are separate but related constructs. However, the relationship between Personality Assessment Inventory (PAI) SVTs and PVTs has not been explored. This study aimed to replicate previous MMPI research using the PAI, exploring the relationship between PVTs and overreporting SVTs across three subsamples, neurodevelopmental (attention deficit-hyperactivity disorder (ADHD)/learning disorder), psychiatric, and mild traumatic brain injury (mTBI).

METHODS

Participants included 561 consecutive referrals who completed the Test of Memory Malingering (TOMM) and the PAI. Three subgroups were created based on referral question. The relationship between PAI SVTs and the PVT was evaluated through multiple regression analysis.

RESULTS

The results demonstrated the relationship between PAI symptom overreporting SVTs, including Negative Impression Management (NIM), Malingering Index (MAL), and Cognitive Bias Scale (CBS), and PVTs varied by referral subgroup. Specifically, overreporting on CBS but not NIM and MAL significantly predicted poorer PVT performance in the full sample and the mTBI sample. In contrast, none of the overreporting SVTs significantly predicted PVT performance in the ADHD/learning disorder sample but conversely, all SVTs predicted PVT performance in the psychiatric sample.

CONCLUSIONS

The results partially replicated prior research comparing SVTs and PVTs and suggested that constructs measured by SVTs and PVTs vary depending upon population. The results support the necessity of both PVTs and SVTs in clinical neuropsychological practice.

Cross-validating the Clinical Assessment of Attention Deficit-Adult symptom validity scales for assessment of attention deficit/hyperactivity disorder in adults

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.

The Impact of Adverse Childhood Experiences on Symptom and Performance Validity Tests Among a Multiracial Sample Presenting for ADHD Evaluation

OBJECTIVE

Adverse childhood experiences (ACEs) are commonly reported in individuals presenting for attention-deficit hyperactivity disorder (ADHD) evaluation. Performance validity tests (PVTs) and symptom validity tests (SVTs) are essential to ADHD evaluations in young adults, but extant research suggests that those who report ACEs may be inaccurately classified as invalid on these measures. The current study aimed to assess the degree to which ACE exposure differentiated PVT and SVT performance and ADHD symptom reporting in a multi-racial sample of adults presenting for ADHD evaluation.

METHOD

This study included 170 adults referred for outpatient neuropsychological ADHD evaluation who completed the ACE Checklist and a neurocognitive battery that included multiple PVTs and SVTs. Analysis of variance was used to examine differences in PVT and SVT performance among those with high (≥4) and low (≤3) reported ACEs.

RESULTS

Main effects of the ACE group were observed, such that high ACE group reporting demonstrated higher scores on SVTs assessing ADHD symptom over-reporting and infrequent psychiatric and somatic symptoms on the Minnesota Multiphasic Personality Inventory-2-Restructured Form. Conversely, no significant differences emerged in total PVT failures across ACE groups.

CONCLUSIONS

Those with high ACE exposure were more likely to have higher scores on SVTs assessing over-reporting and infrequent responses. In contrast, ACE exposure did not affect PVT performance. Thus, ACE exposure should be considered specifically when evaluating SVT performance in the context of ADHD evaluations, and more work is needed to understand factors that contribute to different patterns of symptom reporting as a function of ACE exposure.

Minnesota Multiphasic Personality Inventory-2-Restructured Form Profiles Among Adults With Attention-Deficit/Hyperactivity Disorder: Examining the Effect of Comorbid Psychopathology and ADHD Presentation

OBJECTIVE

Despite widespread use of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF), it is surprisingly understudied among adults with attention-deficit/hyperactivity disorder (ADHD). This is significant as ADHD is a frequent referral for neuropsychological evaluation; however, the core symptom of attention difficulty is a nonspecific sequela of many psychological disorders. This study aimed to characterize MMPI-2-RF profiles among adults with ADHD and examine the effect of comorbid psychopathology.

METHOD

A large, demographically diverse sample of 413 consecutive adults referred for neuropsychological evaluation to assist with differential diagnosis of ADHD who completed the MMPI-2-RF was examined. Profiles of the 145 patients diagnosed with ADHD-only were compared to 192 with ADHD and a comorbid psychological disorder and a 55-patient non-ADHD psychiatric comparison group. Among the ADHD-only group, profiles also were compared based on ADHD-presentation type (Predominantly Inattentive vs. Combined presentation).

RESULTS

The ADHD/psychopathology and psychiatric comparison groups scored higher than the ADHD-only group across nearly all scales with widespread clinical elevations. Conversely, the ADHD-only group displayed an isolated elevation on the Cognitive Complaints scale. Comparison between ADHD presentations revealed several small-moderate significant differences, the largest of which occurred on the Externalizing and Interpersonal scales.

CONCLUSIONS

Adults with ADHD alone, and no other psychopathology have a unique MMPI-2-RF profile characterized by isolated elevation on the Cognitive Complaints scale. These results support use of the MMPI-2-RF in assessment of adults with ADHD as it can help distinguish ADHD alone from ADHD/comorbid psychopathology and identify relevant psychiatric comorbidities that may be contributing to patients' inattention complaints.

Cognitive Underperformance in a Mixed Neuropsychiatric Sample at Diagnostic Evaluation of Adult ADHD

(1) Background: The clinical assessment of attention-deficit/hyperactivity disorder (ADHD) in adulthood is known to show non-trivial base rates of noncredible performance and requires thorough validity assessment. (2) Objectives: The present study estimated base rates of noncredible performance in clinical evaluations of adult ADHD on one or more of 17 embedded validity indicators (EVIs). This study further examines the effect of the order of test administration on EVI failure rates, the association between cognitive underperformance and symptom overreporting, and the prediction of cognitive underperformance by clinical information. (3) Methods: A mixed neuropsychiatric sample (N = 464, ADHD = 227) completed a comprehensive neuropsychological assessment battery on the Vienna Test System (VTS; CFADHD). Test performance allows the computation of 17 embedded performance validity indicators (PVTs) derived from eight different neuropsychological tests. Further, all participants completed several self- and other-report symptom rating scales assessing depressive symptoms and cognitive functioning. The Conners' Adult ADHD Rating Scale and the Beck Depression Inventory-II were administered to derive embedded symptom validity measures (SVTs). (4) Results and conclusion: Noncredible performance occurs in a sizeable proportion of about 10% up to 30% of individuals throughout the entire battery. Tests for attention and concentration appear to be the most adequate and sensitive for detecting underperformance. Cognitive underperformance represents a coherent construct and seems dissociable from symptom overreporting. These results emphasize the importance of performing multiple PVTs, at different time points, and promote more accurate calculation of the positive and negative predictive values of a given validity measure for noncredible performance during clinical assessments. Future studies should further examine whether and how the present results stand in other clinical populations, by implementing rigorous reference standards of noncredible performance, characterizing those failing PVT assessments, and differentiating between underlying motivations.

Performance and symptom validity assessment in attention deficit/hyperactivity disorder: Base rates of invalidity, concordance, and relative impact on cognitive performance

Objective: Differential diagnosis of attention deficit/hyperactivity disorder (ADHD) is one of the most common referral questions for neuropsychological evaluation but is complicated by the presence of external incentives. Validity assessment is therefore critical in such evaluations, employing symptom validity tests (SVTs) and performance validity tests (PVTs) to assess the validity of reported symptoms and cognitive test performance, respectively. This study aimed to establish the base rate of symptom and performance invalidity in adults referred for ADHD, compare concordance between performance and symptom validity, and assess the impact of each type of validity on cognitive test performance. Method: This consecutive case series included data from 392 demographically-diverse adults who underwent outpatient neuropsychological evaluation for ADHD. All patients were administered the Clinical Assessment of Attention Deficit-Adult (CAT-A) and a uniform cognitive test battery, including seven PVTs. Results: Invalid symptom reporting and PVT performance were found in 22% and 16% of the sample, respectively. Sixty-eight percent had concordantly valid SVTs/PVTs and 6% had invalid SVTs/PVTs, whereas the remaining 26% had either invalid SVTs or PVTs (but not both). Invalid PVT performance resulted in a significant decrease across all cognitive test scores, with generally large effects (ηp2=.01-.18). Invalid symptom reporting had minimal effects on cognitive test performance (ηp2= ≤.04). Conclusions: PVTs and SVTs are dissociable and therefore should not be used interchangeably in the context of adult ADHD evaluations. Rather, symptom and performance validity should continue to be assessed independently as they provide largely non-redundant information.

Multivariate examination of embedded indicators of performance validity for ADHD evaluations: A targeted approach

This study investigated the individual and combined utility of 10 embedded validity indicators (EVIs) within executive functioning, attention/working memory, and processing speed measures in 585 adults referred for an attention-deficit/hyperactivity disorder (ADHD) evaluation. Participants were categorized into invalid and valid performance groups as determined by scores from empirical performance validity indicators. Analyses revealed that all of the EVIs could meaningfully discriminate invalid from valid performers (AUCs = .69-.78), with high specificity (≥90%) but low sensitivity (19%-51%). However, none of them explained more than 20% of the variance in validity status. Combining any of these 10 EVIs into a multivariate model significantly improved classification accuracy, explaining up to 36% of the variance in validity status. Integrating six EVIs from the Stroop Color and Word Test, Trail Making Test, Verbal Fluency Test, and Wechsler Adult Intelligence Scale-Fourth Edition was as efficacious (AUC = .86) as using all 10 EVIs together. Failing any two of these six EVIs or any three of the 10 EVIs yielded clinically acceptable specificity (≥90%) with moderate sensitivity (60%). Findings support the use of multivariate models to improve the identification of performance invalidity in ADHD evaluations, but chaining multiple EVIs may only be helpful to an extent.

Cognitive Performance and Psychiatric Self-Reports Across Adult Cognitive Disengagement Syndrome and ADHD Diagnostic Groups

OBJECTIVE

Cognitive disengagement syndrome (CDS) is characterized by inattention, under-arousal, and fatigue and frequently co-occurs with attention-deficit/hyperactivity disorder (ADHD). Although CDS is associated with cognitive complaints, its association with objective cognitive performance is less well understood.

METHOD

This study investigated neuropsychological correlates of CDS symptoms among 169 adults (M_age = 29.4) referred for outpatient neuropsychological evaluation following inattention complaints. We evaluated cognitive and self-report differences across four high/low CDS and positive/negative ADHD groups, and cognitive and self-report correlates of CDS symptomology.

RESULTS

There were no differences in cognitive performance, significant differences in self-reported psychiatric symptoms (greater CDS symptomatology, impulsivity among the high CDS groups; greater inattention among the positive ADHD/high CDS groups; greater hyperactivity among the positive ADHD groups), significant intercorrelations within cognitive and self-report measures, nonsignificant correlations between cognitive measures and self-report measures.

CONCLUSION

Findings support prior work demonstrating weak to null associations between ADHD and CDS symptoms and cognitive performance among adults.

Assessment of learning and memory impairments in adults with predominately inattentive versus combined presentation attention-deficit/hyperactivity disorder

This cross-sectional study compared adults diagnosed with Attention-Deficit/Hyperactivity Disorder-Inattentive (ADHD-I) and ADHD-Combined (ADHD-C) presentations with a non-ADHD group on verbal and visual learning and delayed recall using the Rey Auditory Verbal Learning Test (RAVLT) and Brief Visuospatial Memory Test-Revised (BVMT-R), respectively. Data from 380 predominately college student adult outpatients were used, with 155 who met criteria for ADHD-I, 165 who met criteria for ADHD-C, and 60 who did not meet criteria for ADHD but were diagnosed with a primary depressive or anxiety disorder or received no diagnosis. Each patient was administered the RAVLT and BVMT-R as part of a comprehensive neuropsychological evaluation. Significant main effects of study group were found, such that patients with ADHD-C demonstrated worse learning and delayed recall of both verbal and visual information than patients with ADHD-I and the non-ADHD group. Patients with ADHD-I performed comparably to the non-ADHD group, apart from visual learning and delayed recall. Notably, more patients in the ADHD groups had possible or probable learning and memory impairment compared to the non-ADHD group. Findings were consistent with previous research indicating that those with ADHD exhibit poorer verbal and visual learning and delayed recall than those without ADHD.

Comprehensive Analysis of MMPI-2-RF Symptom Validity Scales and Performance Validity Test Relationships in a Diverse Mixed Neuropsychiatric Setting

The utility of symptom (SVT) and performance (PVT) validity tests has been independently established in neuropsychological evaluations, yet research on the relationship between these two types of validity indices is limited to circumscribed populations and measures. This study examined the relationship between SVTs on the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and PVTs in a mixed neuropsychiatric setting. This cross-sectional study included data from 181 diagnostically and demographically diverse patients with neuropsychiatric conditions referred for outpatient clinical neuropsychological evaluation at an academic medical center. All patients were administered a uniform neuropsychological battery, including the MMPI-2-RF and five PVTs (i.e., Dot Counting Test; Medical Symptom Validity Test; Reliable Digit Span; Test of Memory Malingering-Trial 1; Word Choice Test). Nonsignificant associations emerged between SVT and PVT performance. Although the Response Bias Scale was most predictive of PVT performance, MMPI-2-RF SVTs generally had low classification accuracy for predicting PVT performance. Neuropsychological test performance was related to MMPI-2-RF SVT status only when overreporting elevations were at extreme scores. The current study further supports that SVTs and PVTs measure unique and dissociable constructs among diverse patients with neuropsychiatric conditions, consistent with literature from other clinical contexts. Therefore, objective evidence of symptom overreporting on MMPI-2-RF SVTs cannot be interpreted as definitively indicating invalid performance on tests of neurocognitive abilities. As such, clinicians should include both SVTs and PVTs as part of a comprehensive neuropsychological evaluation as they provide unique information regarding performance and symptom validity.

Detecting feigned ADHD in college students using the Minnesota multiphasic personality inventory-2-restructured form (MMPI-2-RF)

Objective: To investigate the utility of the validity scales of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) for detecting feigned Attention-Deficit Hyperreactivity Disorder (ADHD), we utilized a simulation design. Method: We examined group differences across the Restructured Clinical (RC) and validity scales as well as the classification ability of the validity scales across three cut scores. Analyses were conducted across five simulation groups (N = 177) and a standard instruction group (N = 32). Results: Across most of the RC and validity scales, those feigning ADHD produced significantly higher scores than the standard instruction group, but generally no significant differences between the feigning groups were demonstrated. The most promising scales for detecting feigned ADHD were F-r, Fp-r, and Fs at cut scores in the 70 T to 80 T range, respectively. Conclusions: Results support the use of the MMPI-2-RF in ADHD evaluations with scores on F-r, Fs, and Fp-r being particularly useful in detecting feigned ADHD in college students. However, there was no evidence to support the feigning of distinct ADHD symptoms presentations.

Symptom and performance validity in samples of adults at clinical evaluation of ADHD: a replication study using machine learning algorithms

INTRODUCTION

Research has shown non-trivial base rates of noncredible symptom report and performance in the clinical evaluation of attention-deficit/hyperactivity disorder (ADHD) in adulthood. The goal of this study is to estimate and replicate base rates of symptom and performance validity test failure in the clinical evaluation of adult ADHD and derive prediction models based on routine clinical measures.

METHODS

This study reuses data of a previous publication of 196 adults seeking ADHD assessment and replicates the findings on an independent sample of 700 adults recruited in the same referral context. Measures of symptom and performance validity (one SVT, two PVTs) were applied to estimate base rates. Prediction models were developed using machine learning.

RESULTS

Both samples showed substantial rates of noncredible symptom report (one SVT failure: 35.7% - 36.6%), noncredible test performance (one PVT failure: 32.1% - 49.3%; two PVT failures: 18.9% - 27.3%), or both (each one SVT and PVT failure: 13.3% - 22.4%; one SVT and two PVT failures: 9.7% - 13.7%). Machine learning algorithms resulted in generally moderate to weak prediction models, with advantages of the reused sample compared to the independent replication sample. Associations between measures of symptom and performance validity were negligible to small.

CONCLUSIONS

This study highlights the necessity to include measures of symptom and performance validity in the clinical evaluation of adult ADHD. Further, this study demonstrates the difficulty to characterize the group failing symptom or performance validity assessment.

Assessing performance validity during attention-deficit/hyperactivity disorder evaluations: Cross-validation of non-memory embedded validity indicators

Embedded performance validity tests (PVTs) are key components of neuropsychological evaluations. However, most are memory-based and may be less useful in the assessment of attention-deficit/hyperactivity disorder (ADHD). Four non-memory-based validity indices derived from processing speed and executive functioning measures commonly included in ADHD evaluations, namely Verbal Fluency (VF) and the Trail Making Test (TMT), were cross-validated using the Rey 15-Item Test (RFIT) Recall and Recall/Recognition as memory-based comparison measures. This consecutive case series included data from 416 demographically-diverse adults who underwent outpatient neuropsychological evaluation for ADHD. Validity classifications were established, with ≤1 PVT failure of five independent criterion PVTs as indicative of valid performance (374 valid performers/42 invalid performers). Among the statistically significant validity indicators, TMT-A and TMT-B T-scores (AUCs = .707-.723) had acceptable classification accuracy ranges and sensitivities ranging from 29%-36% (≥89% specificity). RFIT Recall/Recognition produced similar results as TMT-B T-score with 42% sensitivity/90% specificity, but with lower classification accuracy. In evaluating adult ADHD, VF and TMT embedded PVTs demonstrated comparable sensitivity and specificity values to those found in other clinical populations but necessitated alternate cut-scores. Results also support use of RFIT Recall/Recognition over the standard RFIT Recall as a PVT for adult ADHD evaluations.

Examining Conners Continuous Performance Test-3 (CPT-3) Embedded Performance Validity Indicators in an Adult Clinical Sample Referred for ADHD Evaluation

This study evaluated multiple previously-identified Continuous Performance Test-Third Edition (CPT-3) scores as embedded validity indicators (EVIs) among 201 adults undergoing neuropsychological evaluation for Attention-Deficit/Hyperactivity Disorder (ADHD) divided into valid (n = 169) and invalid (n = 32) groups based on seven criterion measures. Although 6/10 CPT-3 scores accurately detected invalidity, only two reached minimally acceptable classification accuracy of ≥0.70. The remaining four had unacceptably low accuracy (AUCs = 0.62-0.69) with 0.19-0.41 sensitivity at ≥0.90 specificity. Composite scores did not provide better classification accuracy than individual CPT-3 scores. In sum, CPT-3 individual and composite scores generally are not accurate PVTs among adults undergoing clinical evaluation for ADHD.

Establishing the base rate of performance invalidity in a clinical electrical injury sample: Implications for neuropsychological test performance

Objective: The base rate of neuropsychological performance invalidity in electrical injury, a clinically-distinct and frequently compensation-seeking population, is not well established. This study determined the base rate of performance invalidity in a large electrical injury sample, and examined patient characteristics, injury parameters, and neuropsychological test performance based on validity status.Method: This cross-sectional study included data from 101 patients with electrical injury consecutively referred for post-acute neuropsychological evaluation. Eighty-five percent of the sample was compensation-seeking. Multiple performance validity tests (PVTs) were administered as part of standard clinical evaluation. For patients with four or more PVTs, valid performance was operationalized as less than or equal to one PVT failure and invalid performance as two or more failures.Results: Frequency analysis revealed 66% (n = 67) had valid performance while 29% (n = 29) demonstrated probable invalid performance; the remaining 5% (n = 5) had indeterminate validity. No significant differences in demographics or injury parameters emerged between validity groups (0 vs. 1 vs. ≥2 PVT failures). In contrast, the electrical injury group with invalid performance performed significantly worse across tests of processing speed and executive abilities than those with valid performance (ps< .05, η_p² = .19-.25).Conclusions: The current study is the first to establish the base rate of neuropsychological performance invalidity in electrical injury survivors using empirical methods and current practice standards. Patient and clinical variables, including compensation-seeking status, did not differ between validity groups; however, neuropsychological test performance did, supporting the need for multi-method, objective performance validity assessment.

Concordance between the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) and Clinical Assessment of Attention Deficit-Adult (CAT-A) over-reporting validity scales for detecting invalid ADHD symptom reporting

This study investigated the relationship between symptom validity scales on the Clinical Assessment of Attention Deficit-Adult (CAT-A) and the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) in the context of Attention-Deficit/Hyperactivity Disorder (ADHD) evaluation. The sample comprised 140 consecutive patients referred for a neuropsychological evaluation of ADHD and were administered the CAT-A and the MMPI-2-RF and a battery of performance-based neurocognitive tests. Results indicated CAT-A/MMPI-2-RF symptom validity concordance of 51% between measures, with 38% concordant valid and 13% concordant invalid responses. Among those with discordance symptom validity results, rates of valid CAT-A/invalid MMPI-2-RF responding (41%) were more common than invalid CAT-A/valid MMPI-2-RF responding (8%). Results also indicated higher levels of ADHD symptoms among invalid responding within the CAT-A, whereas the MMPI-2-RF Cognitive Complaints scale did not differ by CAT-A validity status. Finally, symptom validity scales on both the CAT-A and MMPI-2-RF were largely discordant from neuropsychological test validity status per performance validity tests. Findings highlight the need for symptom validity testing when assessing ADHD and indicate that validity indices on broad personality assessments may assess different constructs than embedded validity indices in ADHD-specific measures.

Non-credible symptom report in the clinical evaluation of adult ADHD: development and initial validation of a new validity index embedded in the Conners' adult ADHD rating scales

As attention-deficit/hyperactivity disorder (ADHD) is a feasible target for individuals aiming to procure stimulant medication or accommodations, there is a high clinical need for accurate assessment of adult ADHD. Proven falsifiability of commonly used diagnostic instruments is therefore of concern. The present study aimed to develop a new, ADHD-specific infrequency index to aid the detection of non-credible self-report. Disorder-specific adaptations of four detection strategies were embedded into the Conners’ Adult ADHD Rating Scales (CAARS) and tested for infrequency among credible neurotypical controls (n = 1001) and credible adults with ADHD (n = 100). The new index’ ability to detect instructed simulators (n = 242) and non-credible adults with ADHD (n = 22) was subsequently examined using ROC analyses. Applying a conservative cut-off score, the new index identified 30% of participants instructed to simulate ADHD while retaining a specificity of 98%. Items assessing supposed symptoms of ADHD proved most useful in distinguishing genuine patients with ADHD from simulators, whereas inquiries into unusual symptom combinations produced a small effect. The CAARS Infrequency Index (CII) outperformed the new infrequency index in terms of sensitivity (46%), but not overall classification accuracy as determined in ROC analyses. Neither the new infrequency index nor the CII detected non-credible adults diagnosed with ADHD with adequate accuracy. In contrast, both infrequency indices showed high classification accuracy when used to detect symptom over-report. Findings support the new indices’ utility as an adjunct measure in uncovering feigned ADHD, while underscoring the need to differentiate general over-reporting from specific forms of feigning.