Cognitive correlates of attention-deficit hyperactivity disorder in children and adolescents with high intellectual ability

Do Wechsler intelligence scales predict academic achievement in children with ADHD or autism? A systematic review and meta-analysis

Intelligence tests predict academic achievement in typically developed children, however if this is the case also in children with attention-deficit/hyperactivity disorder (ADHD) and/or autism spectrum disorder (ASD) is not clear. This systematic review and meta-analysis examined if Wechsler intelligence scales predict academic achievement and/or grades in children, ages 6-16 years, with ADHD and/or ASD. We searched the databases PubMed, PsycINFO and Education Research Complete for studies published between 2000 and 2023. We used the Newcastle-Ottawa Scale to assess risk of bias. Narrative synthesis and meta-analysis were performed. Twelve studies (ADHD n = 1,834, ASD n = 176) were included in the review, and six samples (ADHD n = 1,112) of those were included in the meta-analyses. The results of the meta-analyses showed moderate overall weighted correlations between IQ and word reading, written language, and mathematics respectively. Similarly, the overall weighted correlations between processing speed and the aforementioned domains of academic achievement were moderate. Meta-analysis with additional Wechsler scales composite scores could not be conducted. In the narrative synthesis, Full Scale IQ was associated with academic achievement in both ADHD and ASD, and grades in ADHD. The limited number of ASD participants and the heterogeneity of the samples need to be considered when interpreting results. Generally, the results indicate that Wechsler scales are valuable in predicting academic achievement in children with ADHD or ASD. Motivation and other factors related with academic achievement need to be further explored in these groups.

Sex-differential patterns of neuropsychological functioning in adults with attention-deficit/hyperactivity disorder

BACKGROUND

The sex-differential prevalence of attention-deficit/hyperactivity disorder (ADHD) varies across the lifespan, but little is known about sex differences in executive functions in adults with ADHD.

METHODS

We assessed 261 adults, aged 18-40 years, diagnosed with ADHD (170 males [assigned at birth], aged 25.81 ± 5.49; 91 females, aged 27.76 ± 5.42) and 308 neurotypical adults (176 males, aged 24.62 ± 5.14; 132 female, aged 25.37 ± 5.42) via psychiatric interviews to confirm ADHD and other psychiatric diagnoses. They were assessed by the Cambridge Neuropsychological Testing Automated Battery (CANTAB) on Reaction Time (arousal/processing speed), Rapid Visual Information Processing (sustained attention), Spatial Span (spatial memory), Spatial Working Memory, Intradimentional/Extradimensional Shift (set-shifting), and Stocking of Cambridge (spatial planning). The primary analyses were adjusted for age, full-scale IQ, and co-occurring psychiatric conditions.

RESULTS

Adults with ADHD had various co-occurring psychiatric conditions without sex differences in ADHD-neurotypical differences. Both adult males and females with ADHD performed poorer in all CANTAB tasks than same-sex neurotypical adults. Significant sex-moderating effects were observed in neuropsychological performance, including greater ADHD-neurotypical differences in arousal for females than males and in location memory for spatial tasks in males than females.

CONCLUSION

There were no sex-moderating effects in the presence of co-occurring psychiatric conditions in adult ADHD. However, there were sex-moderating effects on how ADHD related to neuropsychological functioning in adulthood. ADHD was associated with more challenges in arousal/processing speed in females and more challenges in strategy use or inhibition in spatial memory in males.

Clinical and Cognitive Features of Attention Deficit Hyperactivity Disorder with Intellectual Giftedness: A Systematic Review

A systematic review was carried out on publications from the last 15 years that have studied the effect of intellectual giftedness, defined as IQ > 115, on the clinical and cognitive features of ADHD. Studies indicate that about 15% of people with high IQ meet ADHD criteria. IQ has shown no effect on the pharmacological treatment, and comorbidity does not differ from that of other children with ADHD. High IQ-ADHD, compared to average IQ-ADHD, tends to show less severity in cognitive and behavioral symptoms, as well as a better prognosis; however high IQ may mask ADHD symptoms delaying diagnosis and treatment.

A Comparative Study of Prison Inmates With and Without ADHD: Which Neuropsychological and Self-Report Measures are Most Effective in Detecting ADHD Within Correctional Services?

OBJECTIVE

In this study we aimed to investigate the screening and diagnostic properties of various self-report instruments to identify measures which most effectively detect ADHD in a correctional sample.

METHOD

The sample consisted of 193 male high security prisoners in Sweden. We investigated if measures of ADHD symptoms, executive functioning, impulsivity, estimated IQ and working memory could differentiate participants with ADHD from those with ASPD or no diagnosis.

RESULTS

Participants with ADHD obtained significantly higher total scores on all included measures. Although we found that some of the measures were more efficient in differentiating ADHD, mean values were generally elevated in the sample.

CONCLUSION

Results demonstrate the importance of investigating psychometric properties in relevant samples to assure a measurement's usefulness in different contexts, in this case a correctional setting, where the high influence of unspecific behavioral indicators in these measurements might negatively affect their validity.

Giftedness and Neurodevelopmental Disorders in Children and Adolescents: A Systematic Review

OBJECTIVE

Throughout the years, several myths have arisen suggesting that children diagnosed with neurodevelopmental disorders possess unusually high abilities in specific domains, depending on the disorder. On the other hand, special skills and talents in children with neurodevelopmental disorders are most commonly overshadowed by their difficulties and overlooked. The purpose of this systematic review is to examine the association between giftedness and neurodevelopmental disorders.

METHODS

The related articles published in PubMed, Google Scholar, PsycINFO, and Embase up to December 31, 2020, as well as their reference lists, were reviewed systematically.

RESULTS

A total of 6069 studies were scanned, and 32 of them (9904 subjects) were deemed eligible for this systematic review. Studies have supported associations between autism spectrum disorders and music ability. Contradictory results have been published regarding associations between giftedness, attention-deficit/hyperactivity disorder, and specific learning disorders. Diagnostic methods seemed to modify associations between giftedness and neurodevelopmental disorders.

CONCLUSION

The dearth of the available evidence is prominent. More research is needed to investigate the field of dual exceptionality. Longitudinal studies are needed, addressing methodological challenges pertaining to variability in the definition of giftedness.

Does IQ Influence Association Between Working Memory and ADHD Symptoms in Young Adults?

OBJECTIVE

This study examined the association between WM and ADHD symptoms in young adults and whether IQ-score influenced this association.

METHOD

Data from the 1993 Pelotas (Brazil) Birth Cohort Study were analyzed (N = 2,845). Working memory and ADHD symptoms were collected at 22 years. IQ was examined at age 18. Poisson regression with robust variance was used to assess the associations between working memory and ADHD symptoms. We also evaluated whether IQ modified associations between working memory and ADHD symptoms.

RESULTS

Working memory was negatively associated with Inattention symptoms of ADHD. The association between working memory and hyperactivity-impulsivity symptoms of ADHD varied by IQ.

CONCLUSIONS

This study provides new insights to theories about the relationship between WM and ADHD symptoms as well as the development of interventions aimed at improving the performance of WM in ADHD.

Distinct Latent Profiles of Working Memory and Processing Speed in Adults with ADHD

This study examined the neuropsychological profile of patients with Attention-Deficit/Hyperactivity Disorder (ADHD) based on Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) working memory and processing speed indices. We aimed to establish whether distinct ADHD subtypes emerge based on neuropsychological testing and determine whether ADHD subgroups differ based on neurocognitive and demographic factors in 179 adult patients with ADHD. Latent Profile Analysis (LPA) revealed four discrete latent subgroups within the sample, each with distinct patterns of working memory and processing speed. Classes significantly differed in demographically predicted IQ, education, and self-reported depression and anxiety. Results reveal heterogeneity in cognitive performance in adult ADHD.