Detecting Feigned Attention-Deficit/Hyperactivity Disorder (ADHD): Current Methods and Future Directions

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.

Social functioning in children with ADHD: an examination of inhibition, self-control, and working memory as potential mediators

Children with attention-deficit/hyperactivity disorder (ADHD) experience a host of social problems, in addition to significant impairments in behavioral inhibition, working memory, and self-control. Behavioral inhibition and working memory difficulties have been linked with social functioning deficits, but to date, most studies have examined these neurocognitive problems either in isolation or as an aggregate measure in relation to social problems, and none has considered the role of self-control. Thus, it remains unclear whether all of these executive functions are linked with social problems or if the link can be more parsimoniously explained by construct overlap. Fifty-eight children with ADHD and 63 typically developing (TD) children completed tests assessing self-control, behavioral inhibition, and working memory; parents and teachers rated children's social functioning. Examination of potential indirect effects with the bootstrapping procedure indicated that working memory mediated the relation between group membership (ADHD, TD) and child social functioning based on teacher but not parent ratings. Behavioral inhibition and self-control did not have direct relations with either parent- or teacher-rated social functioning. These findings point to important differences regarding how executive functioning difficulties manifest at school compared to home, as well as the specific executive function components that predict ADHD-related social difficulties.

Validating Embedded Validity Indicators of Feigned ADHD-Associated Cognitive Impairment Using the MOXO-d-CPT

BACKGROUND

The current study aimed to validate the utility of previously established validity indicators derived from MOXO-d-CPT's continuous performance test.

METHOD

Healthy simulators feigned impairment after searching online for relevant information, an ecologically valid coaching condition (n = 39). They were compared to ADHD patients (n = 36) and healthy controls (n = 38).

RESULTS

Simulators performed significantly worse than ADHD patients in all MOXO-d-CPT indices, as well as a scale that integrates their contributions (feigned ADHD scale). Three indices (attention, hyperactivity, and impulsivity) and the latter scale exhibited adequate discriminative capacity. Higher education was associated with an exaggerated impairment among simulators, easing their detection.

CONCLUSION

Similarity between the current study and a previous study which examned the utlity of the MOXO-d-CPT validity indicators, increases our confidence in the efficacy of the latters embedded validity indicators. Though the findings provide initial validation of these validity indicators, generalizing beyond highly functioning participants necessitates further research.

Identifying Feigned ADHD in College Students: Comparing the Multidimensional ADHD Rating Scale to Established Validity Measures

OBJECTIVE

There is increased concern for malingering in ADHD evaluations due to presence of incentives such as accommodations and medications. Although several validity tests are available to classify malingering in non-ADHD populations, there is no test with proven effectiveness to detect feigned ADHD. This study investigated the ability of the MARS Symptom Validity Index 4 (MARS SV-index 4) and two published validity tests (the Word Memory Test [WMT] and Clinical Assessment of Attention Deficit-Adult [CAT-A] Infrequency scale) to detect malingered ADHD.

METHOD

The participants consisted of 68 young adults, 34 with ADHD. Participants completed the MARS, CAT-A, and WMT validity measures.

RESULTS

The MARS SV index-4 demonstrated higher sensitivity rates for simulated malingering (61.8%) at close to optimal specificity (88.2%) compared to two published tests (which had sensitivity <42% at specificity >90%).

CONCLUSION

The MARS shows good ability to detect feigned ADHD and appears to be useful for adult ADHD assessments.

Feigned ADHD Associated Cognitive Impairment: Utility of Integrating an Eye-tracker and the MOXO-dCPT

OBJECTIVE

The current study assessed the utility of eye-movements measures, gathered while participants performed a commercially available Continuous Performance Test (CPT), to detect feigned ADHD-associated cognitive impairment.

METHOD

Healthy simulators (n = 37), ADHD patients (n = 33), and healthy controls (n = 36) performed an eye-tracker integrated MOXO-dCPT and a stand-alone validity indicator.

RESULTS

Simulators gazed significantly longer at regions that were irrelevant for successful MOXO-dCPT performance compared to ADHD patients and healthy controls. This eye-movement measure, however, had lower sensitivity than traditional MOXO-dCPT indices.

DISCUSSION

Gaze direction measures, gathered while performing a CPT, show initial promise as validity indicators. Traditional CPT measures, however, are more sensitive and therefore offer a more promising path for the establishment of CPT-based validity indicators. The current study is an initial exploration of the issue and further evaluation of both theoretical and practical aspects is mandated.

Scores in Self-Report Questionnaires Assessing Adult ADHD Can Be Influenced by Negative Response Bias but Are Unrelated to Performance on Executive Function and Attention Tests

Self-report questionnaires are in widespread use in the assessment of adults with suspected attention-deficit and hyperactivity disorder (ADHD). Notwithstanding the high degree of validity, these questionnaires are considered to possess, their stand-alone use in assessment for adult ADHD may result in false-positive diagnoses due to the risk of negative response bias. Most of the self-report questionnaires in typical use are based on the diagnostic systems DSM-5 or ICD-10. From a neuropsychological point of view, however, testing of various executive function abilities and attentional performance is important in the assessment of adult ADHD. The present study (N = 211) found no evidence linking executive function (working memory and inhibitory processes) and attentional performance (processing speed) to the results of a self-report questionnaire, the ADHS-LE. The number of failures on the three symptom or performance validity tests (SVT/PVT) used provided the sole, and significant, explanation for the response behavior reported on the ADHS-LE. Of these three SVT/PVTs (the German version of the Structured Inventory of Malingered Symptomatology, SIMS, the reliable digit span, and the standard deviation of simple reaction time), only the SIMS was found to be a significant predictor variable. In the clinical context of this study, 32.6% of subjects produced at least one invalid SVT/PVT result. The use of a more conservative criterion—failure on at least two of the three SVT/PVTs deemed to be feigning ADHD—reduced the proportion of participants generating invalid values to 5%.

Joint Consideration of Validity Indicators Embedded in Conners’ Adult ADHD Rating Scales (CAARS)

A decade of research has both illustrated the need for accurate clinical assessment of adult ADHD and brought forward a series of validity indicators assisting this diagnostic process. Several of these indicators have been embedded into Conners’ Adult ADHD Rating Scales (CAARS). As their different theoretical underpinnings offer the opportunity of possible synergy effects, the present study sought to examine whether the item- or index-wise combination of multiple validity indicators benefits classification accuracy. A sample of controls (n = 856) and adults with ADHD (n = 72) answered the CAARS, including the ADHD Credibility Index (ACI) honestly, while a group of instructed simulators (n = 135) completed the instrument as though they had ADHD. First, original CAARS items, which are part of the CAARS Infrequency Index (CII), and items drawn from the ACI were combined into a new CII-ACI-Compound Index. Secondly, existing validity indicators, including suspect T-score elevations and the CII, were considered in combination. Both approaches were evaluated in terms of sensitivity and specificity. The combination of four CII and five ACI items into the CII-ACI-Compound Index yielded a sensitivity between 41 and 51% and an estimated specificity above 87%. Suspect T-score elevations on all three DSM scales emerged as another potentially useful validity indicator with a sensitivity of 45 to 46% and a specificity > 90%. Deeming examinees non-credible whenever two or more validity indicators showed suspect results ensured low false-positive rates (< 10%), but reduced sensitivity significantly. Classifying respondents as non-credible as soon as any given indicator fell into the suspect range resulted in frequent false positives (> 11% of misclassified adults with ADHD). Depending on whether high specificity or high sensitivity is prioritized, such combined considerations offer valuable additions to individual validity indicators. High sensitivity provided by “either/or” combinations could prove useful in screening settings, whereas high stakes settings could benefit from “and” combinations.

The Multidimensional ADHD Rating Scale: A measure of symptoms, impairment, and symptom validity

Objective: Two studies examined the psychometric properties of the Multidimensional ADHD Rating Scale (MARS), which assesses ADHD symptoms, related functional impairment, and symptom validity (SV). Method: Study 1 used MARS item responses from college students with and without ADHD (with some of the latter group assigned to feign ADHD) to create an SV-index, and to identify optimal cut scores for the clinical (symptom and impairment) indexes. Study 2 cross-validated the findings on a new sample. Results: In both studies, malingerers reported more symptoms and impairment than participants with ADHD, who reported more symptoms and impairment than controls. Receiver operating characteristic analyses found very good discrimination of genuine ADHD from control cases by the clinical MARS indexes, and very good discrimination of genuine ADHD from malingered ADHD by the SV-index. Conclusion: This research provides initial support for the effectiveness of the MARS to detect simulated cases of malingering, and to differentiate ADHD from non-ADHD cases in college students.

Detection of Feigned ADHD Using the MOXO-d-CPT

Objective: The objective of this study was to assess the MOXO-d-CPT utility in detecting feigned ADHD and establish cutoffs with adequate specificity and sensitivity. Method: The study had two phases. First, using a prospective design, healthy adults who simulated ADHD were compared with healthy controls and ADHD patients who performed the tasks to the best of their ability (n = 47 per group). Participants performed the MOXO-d-CPT and an established performance validity test (PVT). Second, the MOXO-d-CPT classification accuracy, employed in Phase 1, was retrospectively compared with archival data of 47 ADHD patients and age-matched healthy controls. Results: Simulators performed significantly worse on all MOXO-d-CPT indices than healthy controls and ADHD patients. Three MOXO-d-CPT indices (attention, hyperactivity, impulsivity) and a scale combining these indices showed adequate discriminative capacity. Conclusion: The MOXO-d-CPT showed promise for the detection of feigned ADHD and, pending replication, can be employed for this aim in clinical practice and ADHD research.

Detecting feigned symptoms of depression, anxiety, and ADHD, in college students with the structured inventory of malingered symptomatology

Objective: Research consistently shows how easily students can feign symptoms of ADHD on self-report checklists to determine eligibility for curricular and standardized testing accommodations. However, it is unclear how easily students can feign psychological symptoms to accesses academic accommodations, making the assessment of symptom validity important in both populations.Method: Using a between-subjects design, 75 college students were randomly assigned to one of three groups: (1) coached feigning of ADHD, (2) coached feigning of depression and anxiety (DA), and (3) honest responding (HR). Participants completed the Depression, Anxiety, and Stress Scale (DASS-21) and the Structured Inventory of Malingered Symptomatology (SIMS).Results: The SIMS showed 100% specificity, but low sensitivity (36-52%) for detecting feigned symptoms with different cutoffs. Differences on SIMS subtests were apparent by group with elevated scores for the DA group on the Affective Disorders subscale and elevation for the ADHD group on the Low Intelligence and Amnestic subscales. Participants identified as feigning by the SIMS typically reported more severe symptoms than participants not identified on the DASS-21.Conclusions: The SIMS equally classified the feigned ADHD and DA participants for both cutoff scores utilized. Potential reasons for low sensitivity rates are discussed and future research recommendations are made.

Diagnosing Attention-Deficit/Hyperactivity Disorder (ADHD) in young adults: A qualitative review of the utility of assessment measures and recommendations for improving the diagnostic process

Objective: Identify assessment measures that augment the clinical interview and improve the diagnostic accuracy of adult ADHD assessment.Method: The sometimes limited research literatures concerning the diagnostic efficacies of the clinical interview, standard and novel ADHD behavior rating scales, performance and symptom validity testing, and cognitive tests are critically reviewed.Results: Based on this qualitative review, both clinical interviews alone and ADHD behavior rating scales alone have adequate sensitivity but poor specificity in diagnosing ADHD. Response validity and symptom validity tests have reasonably good sensitivity and very good specificity in detecting invalid symptom presentation. Cognitive test batteries have inadequate sensitivity and specificity in identifying ADHD. Using cognitive tests in conjunction with behavior rating scales significantly improves the specificity of an assessment battery. Executive function behavior rating scales and functional impairment rating scales are unlikely to improve the diagnostic accuracy of ADHD assessment.Conclusions: Based on this review, key clinical interview questions, behavior rating scales, symptom validity tests, and cognitive tests that have promise to enhance current assessment practices are recommended. These are the authors' personal opinions, not consensus standards, or guidelines promulgated by any organization. These measures are incorporated in a practical, somewhat abbreviated, battery that has the potential to improve clinicians' ability to diagnose adult ADHD.