Toddlers With Elevated Autism or ADHD Likelihood Show Lower Executive Function Scores

Toddlers at 20 months of age who carry an elevated likelihood of developing autism or attention-deficit/hyperactivity disorder show measurable reductions in executive function performance compared to peers with low likelihood. Executive function difficulties have long been recognized as a transdiagnostic feature shared across both autism and ADHD, yet the developmental emergence of these difficulties has historically remained elusive due to methodological constraints and a scarcity of standardized assessments tailored for very young children.

To overcome past measurement limitations that frequently yielded null results in cohorts under two years old, the investigators deployed a comprehensive measurement battery that combined direct performance tasks with structured parent reports. The final study cohort comprised 110 children assessed precisely at 20 months of age. Within this sample, 62 toddlers were at elevated likelihood of autism or ADHD due to a first-degree relative with autism or ADHD and/or showing elevated autistic traits. The comparative control group consisted of 48 toddlers evaluated as having a low likelihood of developing either condition.

From these intercorrelated performance metrics and questionnaire observations, the research team derived a unified composite executive function score. Emotion regulation was analysed separately.

Autistic traits were assessed using the ADOS-2 and the Q-CHAT. Concurrently, the researchers calculated a socio-economic circumstance score combining four distinct indicators: parental educational attainment, parental occupational standing, neighborhood deprivation indices, and overall household income. All preregistered hypotheses were evaluated within a single regression model to preserve statistical parsimony and avoid cumulative error.

The initial statistical modeling demonstrated that toddlers in the elevated-likelihood group exhibited significantly lower composite executive function scores relative to low-likelihood peers, yielding a standardized coefficient of beta equals minus 0.40, a p-value of 0.04, and accounting for four percent of the variance. However, subsequent multivariable regression revealed that this group difference was fully attenuated after entering measured autistic traits into the equation. In this adjusted model, ADOS-2 scores demonstrated a robust independent negative association with executive function (beta equals minus 0.46, p less than 0.001), while the group likelihood coefficient dropped to beta equals 0.05 with a nonsignificant p-value of 0.79, bringing the explained variance to 21 percent.

The inclusion of socio-economic circumstances provided minimal additional explanatory power regarding general executive functioning, contributing a non-significant coefficient of beta equals 0.17 (p equals 0.10) while marginally raising the model variance explained to 23 percent. In contrast, separate analyses revealed distinct dynamics governing emotion regulation. Toddlers at elevated likelihood demonstrated substantially lower baseline emotion regulation scores (beta equals minus 0.69, p less than 0.001, accounting for 12 percent of variance), but this specific difficulty showed no meaningful statistical association with autistic traits, yielding a non-significant p-value of 0.89.

Socio-economic circumstances exerted a notable partial influence on emotion regulation outcomes. When incorporated into the regression model, higher socio-economic circumstance scores were positively associated with better emotion regulation (beta equals 0.35, p less than 0.01). While this environmental factor partly attenuated the group disparity, the elevated-likelihood classification remained a statistically significant predictor of lower emotion regulation (beta equals minus 0.51, p equals 0.02), with the full model accounting for 20 percent of total variance.

The researchers noted that detecting these relative executive function difficulties earlier than previously reported was likely due to their more comprehensive measurement approach. The findings suggest that relative executive function difficulties can serve as meaningful transdiagnostic markers across autism and ADHD well before standard diagnostic ages.

Subject of Research: Early executive function development in toddlers with elevated likelihood of autism or ADHD

Article Title: Executive function scores are lower for 20-month-olds with an elevated likelihood of autism and/or ADHD

Article References: McKinney, A., Bansal, A., Nosyk, M., Maheshwari, D., Croke, C., Luthra, N., Anderle, F., Charman, T., Scerif, G., Rhodes, S., & Hendry, A. (2026). Executive function scores are lower for 20-month-olds with an elevated likelihood of autism and/or ADHD. BMC Pediatrics. https://doi.org/10.1186/s12887-026-07778-3

Image Credits: AI Generated

DOI: 10.1186/s12887-026-07778-3

Keywords: executive function, autism, ADHD, toddler development, early childhood, neurodevelopment, Early Executive Functions Questionnaire, ADOS-2, Q-CHAT, emotion regulation, socio-economic circumstances, transdiagnostic indicators, pediatric psychology, early intervention, longitudinal assessment, behavioral measurement