The relationship between cognition and mathematics in children with attention-deficit/hyperactivity disorder: a systematic review

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.

Prevalence of attention-deficit hyperactivity disorder in children, adolescents and adults in the Middle East and North Africa region: a systematic review and meta-analysis

OBJECTIVES

To systematically estimate the overall prevalence of attention-deficit hyperactivity disorder (ADHD) in children, adolescents and adults across the Middle East and North Africa (MENA) region.

DESIGN

Systematic review and meta-analysis conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement.

DATA SOURCES

Medline and Scopus databases were comprehensively and systematically searched between 1990 and February 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included all cross-sectional or cohort studies that diagnosed ADHD using validated diagnostic tools (eg, Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria, ADHD rating scales and ADHD diagnostic interview) or non-validated tools (eg, brain imaging techniques, computerised cognitive tests and quantitative electroencephalography).

DATA EXTRACTION AND SYNTHESIS

Two reviewers performed the data extraction independently using standardised data collection sheet. Newcastle-Ottawa Scale was used to assess the quality of the included studies. Individualised and pooled event rate and upper and lower limit at 95% CI were calculated according to the ADHD cases and the total sample size using a random-effect model. The subgroup prevalence analyses according to ADHD subtypes, gender, MENA country and age were also performed.

RESULTS

A total of 63 articles met the inclusion criteria involving 849 902 participants. The overall prevalence of ADHD was 10.3% (95% CI 0.081 to 0.129). The prevalence rate ranged from 1.3% (Yemen) to 22.2% (Iran). Subgroup analyses showed that the prevalence in adults was 13.5 and 10.1 in children and adolescents. Males exhibited significantly higher prevalence compared with females as these were 11.1% and 7%, respectively. Attention-deficit subtype was significantly the most prevalent (46.7%) compared with hyperactivity/impulsivity (33.7%) and combined types (20.6%).

CONCLUSION

The overall prevalence of ADHD was high in the MENA region. It is crucial to allocate more attention and resources towards the prevention and treatment of ADHD in children, adolescents and adults within the region.