Reexamining performance validity cutoffs within the Complex Ideational Material and the Boston Naming Test–Short Form using an experimental malingering paradigm

Replicating a Meta-Analysis: The Search for the Optimal Word Choice Test Cutoff Continues

This study was designed to expand on a recent meta-analysis that identified ≤42 as the optimal cutoff on the Word Choice Test (WCT). We examined the base rate of failure and the classification accuracy of various WCT cutoffs in four independent clinical samples (N = 252) against various psychometrically defined criterion groups. WCT ≤ 47 achieved acceptable combinations of specificity (.86-.89) at .49 to .54 sensitivity. Lowering the cutoff to ≤45 improved specificity (.91-.98) at a reasonable cost to sensitivity (.39-.50). Making the cutoff even more conservative (≤42) disproportionately sacrificed sensitivity (.30-.38) for specificity (.98-1.00), while still classifying 26.7% of patients with genuine and severe deficits as non-credible. Critical item (.23-.45 sensitivity at .89-1.00 specificity) and time-to-completion cutoffs (.48-.71 sensitivity at .87-.96 specificity) were effective alternative/complementary detection methods. Although WCT ≤ 45 produced the best overall classification accuracy, scores in the 43 to 47 range provide comparable objective psychometric evidence of non-credible responding. Results question the need for designating a single cutoff as "optimal," given the heterogeneity of signal detection environments in which individual assessors operate. As meta-analyses often fail to replicate, ongoing research is needed on the classification accuracy of various WCT cutoffs.

Multivariate models provide an effective psychometric solution to the variability in classification accuracy of D-KEFS Stroop performance validity cutoffs

ObjectiveThe study was designed to expand on the results of previous investigations on the D-KEFS Stroop as a performance validity test (PVT), which produced diverging conclusions. Method The classification accuracy of previously proposed validity cutoffs on the D-KEFS Stroop was computed against four different criterion PVTs in two independent samples: patients with uncomplicated mild TBI (n = 68) and disability benefit applicants (n = 49). Results Age-corrected scaled scores (ACSSs) ≤6 on individual subtests often fell short of specificity standards. Making the cutoffs more conservative improved specificity, but at a significant cost to sensitivity. In contrast, multivariate models (≥3 failures at ACSS ≤6 or ≥2 failures at ACSS ≤5 on the four subtests) produced good combinations of sensitivity (.39-.79) and specificity (.85-1.00), correctly classifying 74.6-90.6% of the sample. A novel validity scale, the D-KEFS Stroop Index correctly classified between 78.7% and 93.3% of the sample. Conclusions A multivariate approach to performance validity assessment provides a methodological safeguard against sample- and instrument-specific fluctuations in classification accuracy, strikes a reasonable balance between sensitivity and specificity, and mitigates the invalid before impaired paradox.

Attention Performance as an Embedded Validity Indicator in the Cognitive Assessment of Early Retirement Claimants

The assessment of performance validity is essential in any neuropsychological evaluation. However, relatively few measures exist that are based on attention performance embedded within routine cognitive tasks. The present study explores the potential value of a computerized attention test, the Cognitrone, as an embedded validity indicator in the neuropsychological assessment of early retirement claimants. Two hundred and sixty-five early retirement claimants were assessed with the Word Memory Test (WMT) and the Cognitrone. WMT scores were used as the independent criterion to determine performance validity. Speed and accuracy measures of the Cognitrone were analyzed in receiver operating characteristics (ROC) to classify group membership. The Cognitrone was sensitive in revealing attention deficits in early retirement claimants. Further, 54% (n = 143) of the individuals showed noncredible cognitive performance, whereas 46% (n = 122) showed credible cognitive performance. Individuals failing the performance validity assessment showed slower (AUC = 79.1%) and more inaccurate (AUC = 79.5%) attention performance than those passing the performance validity assessment. A compound score integrating speed and accuracy revealed incremental value as indicated by AUC = 87.9%. Various cut scores are suggested, resulting in equal rates of 80% sensitivity and specificity (cut score = 1.297) or 69% sensitivity with 90% specificity (cut score = 0.734). The present study supports the sensitivity of the Cognitrone for the assessment of attention deficits in early retirement claimants and its potential value as an embedded validity indicator. Further research on different samples and with multidimensional criteria for determining invalid performance are required before clinical application can be suggested.

Utility of WAIS-IV Digit Span indices as measures of performance validity in moderate to severe traumatic brain injury

Objective: The addition of Sequencing to WAIS-IV Digit Span (DS) brought about new Reliable Digit Span (RDS) indices and an Age-Corrected Scaled Score that includes Sequencing trials. Reports have indicated that these new performance validity tests (PVTs) are superior to the traditional RDS; however, comparisons in the context of known neurocognitive impairment are sparse. This study compared DS-derived PVT classification accuracies in a design that included adults with verified TBI. Methods: Participants included 64 adults with moderate-to-severe TBI (TBI), 51 healthy adults coached to simulate TBI (SIM), and 78 healthy comparisons (HC). Participants completed the WAIS-IV DS subtest in the context of a larger test battery. Results: Kruskal-Wallis tests indicated that all DS indices differed significantly across groups. Post hoc contrasts revealed that only RDS Forward and the traditional RDS differed significantly between SIM and TBI. ROC analyses indicated that RDS variables were comparable predictors of SIM vs. HC; however, the traditional RDS showed the highest sensitivity when approximating 90% specificity for SIM vs. TBI. A greater percentage of TBI scored RDS Sequencing < 1 compared to SIM and HC. Conclusion: In the context of moderate-to-severe TBI, the DS-derived PVTs showed comparable discriminability. However, the Greiffenstein et al. traditional RDS demonstrated the best classification accuracy with respect to specificity/sensitivity balance. This relative superiority may reflect that individuals with verified TBI are more likely to perseverate on prior instructions during DS Sequencing. Findings highlight the importance of including individuals with verified TBI when evaluating and developing PVTs.

Cross-Cultural Performance Validity Testing: Managing False Positives in Examinees with Limited English Proficiency

Base rates of failure (BR_Fail) on performance validity tests (PVTs) were examined in university students with limited English proficiency (LEP). BR_Fail was calculated for several free-standing and embedded PVTs. All free-standing PVTs and certain embedded indicators were robust to LEP. However, LEP was associated with unacceptably high BR_Fail (20-50%) on several embedded PVTs with high levels of verbal mediation (even multivariate models of PVT could not contain BR_Fail). In conclusion, failing free-standing/dedicated PVTs cannot be attributed to LEP. However, the elevated BR_Fail on several embedded PVTs in university students suggest an unacceptably high overall risk of false positives associated with LEP.

BNT-15: Revised Performance Validity Cutoffs and Proposed Clinical Classification Ranges

BACKGROUND

Abbreviated neurocognitive tests offer a practical alternative to full-length versions but often lack clear interpretive guidelines, thereby limiting their clinical utility.

OBJECTIVE

To replicate validity cutoffs for the Boston Naming Test-Short Form (BNT-15) and to introduce a clinical classification system for the BNT-15 as a measure of object-naming skills.

METHOD

We collected data from 43 university students and 46 clinical patients. Classification accuracy was computed against psychometrically defined criterion groups. Clinical classification ranges were developed using a z -score transformation.

RESULTS

Previously suggested validity cutoffs (≤11 and ≤12) produced comparable classification accuracy among the university students. However, a more conservative cutoff (≤10) was needed with the clinical patients to contain the false-positive rate (0.20-0.38 sensitivity at 0.92-0.96 specificity). As a measure of cognitive ability, a perfect BNT-15 score suggests above average performance; ≤11 suggests clinically significant deficits. Demographically adjusted prorated BNT-15 T-scores correlated strongly (0.86) with the newly developed z -scores.

CONCLUSION

Given its brevity (<5 minutes), ease of administration and scoring, the BNT-15 can function as a useful and cost-effective screening measure for both object-naming/English proficiency and performance validity. The proposed clinical classification ranges provide useful guidelines for practitioners.

Multivariate Models of Performance Validity: The Erdodi Index Captures the Dual Nature of Non-Credible Responding (Continuous and Categorical)

This study was designed to examine the classification accuracy of the Erdodi Index (EI-5), a novel method for aggregating validity indicators that takes into account both the number and extent of performance validity test (PVT) failures. Archival data were collected from a mixed clinical/forensic sample of 452 adults referred for neuropsychological assessment. The classification accuracy of the EI-5 was evaluated against established free-standing PVTs. The EI-5 achieved a good combination of sensitivity (.65) and specificity (.97), correctly classifying 92% of the sample. Its classification accuracy was comparable with that of another free-standing PVT. An indeterminate range between Pass and Fail emerged as a legitimate third outcome of performance validity assessment, indicating that the underlying construct is an inherently continuous variable. Results support the use of the EI model as a practical and psychometrically sound method of aggregating multiple embedded PVTs into a single-number summary of performance validity. Combining free-standing PVTs with the EI-5 resulted in a better separation between credible and non-credible profiles, demonstrating incremental validity. Findings are consistent with recent endorsements of a three-way outcome for PVTs (Pass, Borderline, and Fail).

The BNT-15 provides an accurate measure of English proficiency in cognitively intact bilinguals - a study in cross-cultural assessment

This study was designed to replicate earlier reports of the utility of the Boston Naming Test - Short Form (BNT-15) as an index of limited English proficiency (LEP). Twenty-eight English-Arabic bilingual student volunteers were administered the BNT-15 as part of a brief battery of cognitive tests. The majority (23) were women, and half had LEP. Mean age was 21.1 years. The BNT-15 was an excellent psychometric marker of LEP status (area under the curve: .990-.995). Participants with LEP underperformed on several cognitive measures (verbal comprehension, visuomotor processing speed, single word reading, and performance validity tests). Although no participant with LEP failed the accuracy cutoff on the Word Choice Test, 35.7% of them failed the time cutoff. Overall, LEP was associated with an increased risk of failing performance validity tests. Previously published BNT-15 validity cutoffs had unacceptably low specificity (.33-.52) among participants with LEP. The BNT-15 has the potential to serve as a quick and effective objective measure of LEP. Students with LEP may need academic accommodations to compensate for slower test completion time. Likewise, LEP status should be considered for exemption from failing performance validity tests to protect against false positive errors.

Failing Performance Validity Cutoffs on the Boston Naming Test (BNT) Is Specific, but Insensitive to Non-Credible Responding

This study was designed to examine alternative validity cutoffs on the Boston Naming Test (BNT).Archival data were collected from 206 adults assessed in a medicolegal setting following a motor vehicle collision. Classification accuracy was evaluated against three criterion PVTs.The first cutoff to achieve minimum specificity (.87-.88) was T ≤ 35, at .33-.45 sensitivity. T ≤ 33 improved specificity (.92-.93) at .24-.34 sensitivity. BNT validity cutoffs correctly classified 67-85% of the sample. Failing the BNT was unrelated to self-reported emotional distress. Although constrained by its low sensitivity, the BNT remains a useful embedded PVT.

Motor Reaction Times as an Embedded Measure of Performance Validity: a Study with a Sample of Austrian Early Retirement Claimants

Among embedded measures of performance validity, reaction time parameters appear to be less common. However, their potential may be underestimated. In the German-speaking countries, reaction time is often examined using the Alertness subtest of the Test of Attention Performance (TAP). Several previous studies have examined its suitability for validity assessment. The current study was conceived to examine a variety of reaction time parameters of the TAP Alertness subtest with a sample of 266 Austrian civil forensic patients. Classification results from the Word Memory Test (WMT) were used as an external indicator to distinguish between valid and invalid symptom presentations. Results demonstrated that the WMT fail group performed worse in reaction time as well as its intraindividual variation across trials when compared to the WMT pass group. Receiver operating characteristic analyses revealed areas under the curve of .775–.804. Logistic regression models indicated the parameter intraindividual variation of motor reaction time with warning sound as being the best predictor for invalid test performance. Suggested cut scores yielded a sensitivity of .62 and a specificity of .90, or .45 and .95, respectively, when the accepted false-positive rate was set lower. The results encourage the use of the Alertness subtest as an embedded measure of performance validity.

Introducing the ImPACT-5: An Empirically Derived Multivariate Validity Composite

OBJECTIVE

To create novel Immediate Post-Concussion and Cognitive Testing (ImPACT)-based embedded validity indicators (EVIs) and to compare the classification accuracy to 4 existing EVIImPACT.

METHOD

The ImPACT was administered to 82 male varsity football players during preseason baseline cognitive testing. The classification accuracy of existing EVIImPACT was compared with a newly developed index (ImPACT-5A and B). The ImPACT-5A represents the number of cutoffs failed on the 5 ImPACT composite scores at a liberal cutoff (0.85 specificity); ImPACT-5B is the sum of failures on conservative cutoffs (≥0.90 specificity).

RESULTS

ImPACT-5A ≥1 was sensitive (0.81), but not specific (0.49) to invalid performance, consistent with EVIImPACT developed by independent researchers (0.68 sensitivity at 0.73-0.75 specificity). Conversely, ImPACT-5B ≥3 was highly specific (0.98), but insensitive (0.22), similar to Default EVIImPACT (0.04 sensitivity at 1.00 specificity). ImPACT-5A ≥3 or ImPACT-5B ≥2 met forensic standards of specificity (0.91-0.93) at 0.33 to 0.37 sensitivity. Also, the ImPACT-5s had the strongest linear relationship with clinically meaningful levels of invalid performance of existing EVIImPACT.

CONCLUSIONS

The ImPACT-5s were superior to the standard EVIImPACT and comparable to existing aftermarket EVIImPACT, with the flexibility to optimize the detection model for either sensitivity or specificity. The wide range of ImPACT-5 cutoffs allows for a more nuanced clinical interpretation.

Critical Item Analysis Enhances the Classification Accuracy of the Logical Memory Recognition Trial as a Performance Validity Indicator

OBJECTIVE

: Replicate previous research on Logical Memory Recognition (LM_Recog) and perform a critical item analysis.

METHOD

: Performance validity was psychometrically operationalized in a mixed clinical sample of 213 adults. Classification of the LM_Recog and nine critical items (CR-9) was computed.

RESULTS

: LM_Recog ≤20 produced a good combination of sensitivity (.30-.35) and specificity (.89-.90). CR-9 ≥5 and ≥6 had comparable classification accuracy. CR-9 ≥5 increased sensitivity by 4% over LM_Recog ≤20; CR-9 ≥6 increased specificity by 6-8% over LM_Recog ≤20; CR-9 ≥7 increased specificity by 8-15%.

CONCLUSIONS

: Critical item analysis enhances the classification accuracy of the optimal LM_Recog cutoff (≤20).

Nonmemory Composite Embedded Performance Validity Formulas in Patients with Multiple Sclerosis

OBJECTIVE

Research regarding performance validity tests (PVTs) in patients with multiple sclerosis (MS) is scant, with recommended batteries for neuropsychological evaluations in this population lacking suggestions to include PVTs. Moreover, limited work has examined embedded PVTs in this population. As previous investigations indicated that nonmemory-based embedded PVTs provide clinical utility in other populations, this study sought to determine if a logistic regression-derived PVT formula can be identified from selected nonmemory variables in a sample of patients with MS.

METHOD

A total of 184 patients (M age = 48.45; 76.6% female) with MS were referred for neuropsychological assessment at a large, Midwestern academic medical center. Patients were placed into "credible" (n = 146) or "noncredible" (n = 38) groups according to performance on standalone PVT. Missing data were imputed with HOTDECK.

RESULTS

Classification statistics for a variety of embedded PVTs were examined, with none appearing psychometrically appropriate in isolation (areas under the curve [AUCs] = .48-.64). Four exponentiated equations were created via logistic regression. Six, five, and three predictor equations yielded acceptable discriminability (AUC = .71-.74) with modest sensitivity (.34-.39) while maintaining good specificity (≥.90). The two predictor equation appeared unacceptable (AUC = .67).

CONCLUSIONS

Results suggest that multivariate combinations of embedded PVTs may provide some clinical utility while minimizing test burden in determining performance validity in patients with MS. Nonetheless, the authors recommend routine inclusion of several PVTs and utilization of comprehensive clinical judgment to maximize signal detection of noncredible performance and avoid incorrect conclusions. Clinical implications, limitations, and avenues for future research are discussed.

The emotion word fluency test as an embedded performance validity indicator - Alone and in a multivariate validity composite

OBJECTIVE

This project was designed to cross-validate existing performance validity cutoffs embedded within measures of verbal fluency (FAS and animals) and develop new ones for the Emotion Word Fluency Test (EWFT), a novel measure of category fluency.

METHOD

The classification accuracy of the verbal fluency tests was examined in two samples (70 cognitively healthy university students and 52 clinical patients) against psychometrically defined criterion measures.

RESULTS

A demographically adjusted T-score of ≤31 on the FAS was specific (.88-.97) to noncredible responding in both samples. Animals T ≤ 29 achieved high specificity (.90-.93) among students at .27-.38 sensitivity. A more conservative cutoff (T ≤ 27) was needed in the patient sample for a similar combination of sensitivity (.24-.45) and specificity (.87-.93). An EWFT raw score ≤5 was highly specific (.94-.97) but insensitive (.10-.18) to invalid performance. Failing multiple cutoffs improved specificity (.90-1.00) at variable sensitivity (.19-.45).

CONCLUSIONS

Results help resolve the inconsistency in previous reports, and confirm the overall utility of existing verbal fluency tests as embedded validity indicators. Multivariate models of performance validity assessment are superior to single indicators. The clinical utility and limitations of the EWFT as a novel measure are discussed.

Flipping the Script: Measuring Both Performance Validity and Cognitive Ability with the Forced Choice Recognition Trial of the RCFT

In this study we attempted to replicate the classification accuracy of the newly introduced Forced Choice Recognition trial (FCR) of the Rey Complex Figure Test (RCFT) in a clinical sample. We administered the RCFT_FCR and the earlier Yes/No Recognition trial from the RCFT to 52 clinically referred patients as part of a comprehensive neuropsychological test battery and incentivized a separate control group of 83 university students to perform well on these measures. We then computed the classification accuracies of both measures against criterion performance validity tests (PVTs) and compared results between the two samples. At previously published validity cutoffs (≤16 & ≤17), the RCFT_FCR remained specific (.84-1.00) to psychometrically defined non-credible responding. Simultaneously, the RCFT_FCR was more sensitive to examinees' natural variability in visual-perceptual and verbal memory skills than the Yes/No Recognition trial. Even after being reduced to a seven-point scale (18-24) by the validity cutoffs, both RCFT recognition scores continued to provide clinically useful information on visual memory. This is the first study to validate the RCFT_FCR as a PVT in a clinical sample. Our data also support its use for measuring cognitive ability. Replication studies with more diverse samples and different criterion measures are still needed before large-scale clinical application of this scale.

This will only take a minute: Time cutoffs are superior to accuracy cutoffs on the forced choice recognition trial of the Hopkins Verbal Learning Test - Revised

OBJECTIVE

This study was designed to evaluate the classification accuracy of the recently introduced forced-choice recognition trial to the Hopkins Verbal Learning Test - Revised (FCR_HVLT-R) as a performance validity test (PVT) in a clinical sample. Time-to-completion (T2C) for FCR_HVLT-R was also examined.

METHOD

Forty-three students were assigned to either the control or the experimental malingering (expMAL) condition. Archival data were collected from 52 adults clinically referred for neuropsychological assessment. Invalid performance was defined using expMAL status, two free-standing PVTs and two validity composites.

RESULTS

Among students, FCR_HVLT-R ≤11 or T2C ≥45 seconds was specific (0.86-0.93) to invalid performance. Among patients, an FCR_HVLT-R ≤11 was specific (0.94-1.00), but relatively insensitive (0.38-0.60) to non-credible responding0. T2C ≥35 s produced notably higher sensitivity (0.71-0.89), but variable specificity (0.83-0.96). The T2C achieved superior overall correct classification (81-86%) compared to the accuracy score (68-77%). The FCR_HVLT-R provided incremental utility in performance validity assessment compared to previously introduced validity cutoffs on Recognition Discrimination.

CONCLUSIONS

Combined with T2C, the FCR_HVLT-R has the potential to function as a quick, inexpensive and effective embedded PVT. The time-cutoff effectively attenuated the low ceiling of the accuracy scores, increasing sensitivity by 19%. Replication in larger and more geographically and demographically diverse samples is needed before the FCR_HVLT-R can be endorsed for routine clinical application.

Mean response latency indices on the Victoria Symptom Validity Test do not contribute meaningful predictive value over accuracy scores for detecting invalid performance

The utility of the Victoria Symptom Validity Test (VSVT) as a performance validity test (PVT) has been primarily established using response accuracy scores. However, the degree to which response latency may contribute to accurate classification of performance invalidity over and above accuracy scores remains understudied. Therefore, this study investigated whether combining VSVT accuracy and response latency scores would increase predictive utility beyond use of accuracy scores alone. Data from a mixed clinical sample of 163 patients, who were administered the VSVT as part of a larger neuropsychological battery, were analyzed. At least four independent criterion PVTs were used to establish validity groups (121 valid/42 invalid). Logistic regression models examining each difficulty level revealed that all VSVT measures were useful in classifying validity groups, both independently and when combined. Individual predictor classification accuracy ranged from 77.9 to 81.6%, indicating acceptable to excellent discriminability across the validity indices. The results of this study support the value of both accuracy and latency scores on the VSVT to identify performance invalidity, although the accuracy scores had superior classification statistics compared to response latency, and mean latency indices provided no unique benefit for classification accuracy beyond dimensional accuracy scores alone.

A Systematic Review and Meta-Analysis of the Diagnostic Accuracy of the Advanced Clinical Solutions Word Choice Test as a Performance Validity Test

Thorough assessment of performance validity has become an established standard of practice in neuropsychological assessment. While there has been a large focus on the development and cross-validation of embedded performance validity tests (PVTs) in recent years, new freestanding PVTs have also been developed, including the Word Choice Test (WCT) as part of the Advanced Clinical Solutions Effort System. And, while the WCT's general utility for identifying invalid performance has been demonstrated in the ensuing decade since its initial publication, optimal cut-scores and associated psychometric properties have varied widely across studies. This study sought to synthesize the existing diagnostic accuracy literature regarding the WCT via a systematic review and to conduct a meta-analysis to determine the performance validity cut-score that best maximizes sensitivity while maintaining acceptable specificity. A systematic search of the literature resulted in 14 studies for synthesis, with eight of those available for meta-analysis. Meta-analytic results revealed an optimal cut-score of ≤ 42 with 54% sensitivity and 93% specificity for identifying invalid neuropsychological test performance. Collectively, the WCT demonstrated adequate diagnostic accuracy as a PVT across a variety of populations. Recommendations for future studies are also provided.

Stronger Together: The Wechsler Adult Intelligence Scale-Fourth Edition as a Multivariate Performance Validity Test in Patients with Traumatic Brain Injury

OBJECTIVE

This study was designed to evaluate the classification accuracy of a multivariate model of performance validity assessment using embedded validity indicators (EVIs) within the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV).

METHOD

Archival data were collected from 100 adults with traumatic brain injury (TBI) consecutively referred for neuropsychological assessment in a clinical setting. The classification accuracy of previously published individual EVIs nested within the WAIS-IV and a composite measure based on six independent EVIs were evaluated against psychometrically defined non-credible performance.

RESULTS

Univariate validity cutoffs based on age-corrected scaled scores on Coding, Symbol Search, Digit Span, Letter-Number-Sequencing, Vocabulary minus Digit Span, and Coding minus Symbol Search were strong predictors of psychometrically defined non-credible responding. Failing ≥3 of these six EVIs at the liberal cutoff improved specificity (.91-.95) over univariate cutoffs (.78-.93). Conversely, failing ≥2 EVIs at the more conservative cutoff increased and stabilized sensitivity (.43-.67) compared to univariate cutoffs (.11-.63) while maintaining consistently high specificity (.93-.95).

CONCLUSIONS

In addition to being a widely used test of cognitive functioning, the WAIS-IV can also function as a measure of performance validity. Consistent with previous research, combining information from multiple EVIs enhanced the classification accuracy of individual cutoffs and provided more stable parameter estimates. If the current findings are replicated in larger, diagnostically and demographically heterogeneous samples, the WAIS-IV has the potential to become a powerful multivariate model of performance validity assessment.

BRIEF SUMMARY

Using a combination of multiple performance validity indicators embedded within the subtests of theWechsler Adult Intelligence Scale, the credibility of the response set can be establishedwith a high level of confidence. Multivariatemodels improve classification accuracy over individual tests. Relying on existing test data is a cost-effective approach to performance validity assessment.

An Inventory of Problems-29 (IOP-29) study investigating feigned schizophrenia and random responding in a British community sample

Compared to other Western countries, malingering research is still relatively scarce in the United Kingdom, partly because only a few brief and easy-to-use symptom validity tests (SVTs) have been validated for use with British test-takers. This online study examined the validity of the Inventory of Problems-29 (IOP-29) in detecting feigned schizophrenia and random responding in 151 British volunteers. Each participant took three IOP-29 test administrations: (a) responding honestly; (b) pretending to suffer from schizophrenia; and (c) responding at random. Additionally, they also responded to a schizotypy measure (O-LIFE) under standard instruction. The IOP-29's feigning scale (FDS) showed excellent validity in discriminating honest responding from feigned schizophrenia (AUC = .99), and its classification accuracy was not significantly affected by the presence of schizotypal traits. Additionally, a recently introduced IOP-29 scale aimed at detecting random responding (RRS) demonstrated very promising results.

Short-term effects of cannabis consumption on cognitive performance in medical cannabis patients

This observational study examined the acute cognitive effects of cannabis. We hypothesized that cognitive performance would be negatively affected by acute cannabis intoxication. Twenty-two medical cannabis patients from Southwestern Ontario completed the study. The majority (n = 13) were male. Mean age was 36.0 years, and mean level of education was 13.7 years. Participants were administered the same brief neurocognitive battery three times during a six-hour period: at baseline ("Baseline"), once after they consumed a 20% THC cannabis product ("THC"), and once again several hours later ("Recovery"). The average self-reported level of cannabis intoxication prior to the second assessment (i.e., during THC) was 5.1 out of 10. Contrary to expectations, performance on neuropsychological tests remained stable or even improved during the acute intoxication stage (THC; d: .49-.65, medium effect), and continued to increase during Recovery (d: .45-.77, medium-large effect). Interestingly, the failure rate on performance validity indicators increased during THC. Contrary to our hypothesis, there was no psychometric evidence for a decline in cognitive ability following THC intoxication. There are several possible explanations for this finding but, in the absence of a control group, no definitive conclusion can be reached at this time.

Impact of criterion measures on the classification accuracy of TOMM-1

This study was designed to examine the effect of various criterion measures on the classification accuracy of Trial 1 of the Test of Memory Malingering (TOMM-1), a free-standing performance validity test (PVT). Archival data were collected from a case sequence of 91 (M _Age = 42.2 years; M _Education = 12.7) patients clinically referred for neuropsychological assessment. Trials 2 and Retention of the TOMM, the Word Choice Test, and three validity composites were used as criterion PVTs. Classification accuracy varied systematically as a function of criterion PVT. TOMM-1 ≤ 43 emerged as the optimal cutoff, resulting in a wide range of sensitivity (.47-1.00), with perfect overall specificity. Failing the TOMM-1 was unrelated to age, education or gender, but was associated with elevated self-reported depression. Results support the utility of TOMM-1 as an independent, free-standing, single-trial PVT. Consistent with previous reports, the choice of criterion measure influences parameter estimates of the PVT being calibrated. The methodological implications of modality specificity to PVT research and clinical/forensic practice should be considered when evaluating cutoffs or interpreting scores in the failing range.