Developing ADHD in preschool: Testing the dual pathway model of temperament

Delineating early developmental pathways to ADHD: Setting an international research agenda

Background

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent, impairing, and highly heritable condition typically diagnosed in middle childhood. However, it is now recognized that symptoms emerge much earlier in development. Research focused on understanding-using multiple units of analysis-the cascade of early-life (i.e., prenatal-infant-toddler) developmental changes that will later emerge as ADHD has the potential to transform early identification, prevention, and intervention. To this end, we introduce the recently established Early ADHD Consortium, an international network of investigators engaged in prospective, longitudinal studies of risk for ADHD beginning early in life, conducted within a developmental framework, and which incorporate multimethod approaches. This network seeks to harmonize measures and methodological approaches to increase the potential for data sharing and subsequent impact.

Methods

This perspective paper highlights the importance of investigating pre-diagnostic markers of ADHD, and potential models and mechanisms of ADHD risk and development, with the long-term objective of facilitating development of preemptive interventions that will minimize the impact of ADHD symptoms on everyday functioning and maximize health and developmental outcomes.

Results

We selectively describe key challenges and questions for this field related to theoretical models and developmental mechanisms in ADHD and recommend next steps for the science, including methodological, measurement, and study design considerations. We then describe potential implications for preemptive intervention development. We conclude by considering other issues including ethical concerns and the critical value of incorporating stakeholder input.

Conclusions

It is hoped that this perspective puts forth a research agenda that will enhance collaborative efforts and accelerate progress in understanding developmental mechanisms and the early ADHD phenotype, with implications for early intervention enhancement of healthy development for infants, young children, and their families.

Inhibitory deficits and symptoms of attention-deficit hyperactivity disorder: How are they related to effortful control?

Separate studies with clinical and community-based samples have identified an association between symptoms of attention-deficit hyperactivity disorder (ADHD) and inhibitory control deficits and ADHD and weak effortful control. We tested whether differences in effortful control explained the associations between ADHD symptoms and inhibitory control deficits, controlling for conduct problems. In a community sample, parents rated ADHD symptoms, conduct problems, effortful control, surgency and negative affect in 77 4-7-year-olds (47 girls), who performed an inhibitory control task. ADHD symptoms, deficient inhibitory control and low effortful control were correlated. Controlling for conduct problems, path analysis showed the ADHD symptoms - inhibitory control link was mediated statistically by effortful control. This focuses attention on cognitive-energetic factors associated with ADHD-related executive deficits.

Self-regulation in preschool: Are executive function and effortful control overlapping constructs?

The concepts of executive function (EF) and effortful control (EC) are strikingly similar. EF originate from neurocognitive research and are described as an accumulation of cognitive processes that serve the goal-oriented self-regulation (SR) of an individual. EC originates from temperament research and is defined as the efficiency of executive attention, including the ability to inhibit a dominant response, to activate a subdominant response, to proceed in a planned manner and to recognize conflicts or errors. The aim of this article was to examine the association between the constructs of EF and EC at the preschool-age. Eighty-eight children (49 female; M-age = 3.93 years, SD = .78) were tested with a computerized battery designed to assess EF at 3-6 years of age (EF Touch). Children's parents completed questionnaires assessing EF impairments (BRIEF-P) and EC (CBQ). Associations between the constructs and their conceptual overlap were analyzed using correlations and confirmatory factor analyses. We found significant correlations between EF and EC measures. A one-factor confirmatory model fitted the data very well and indicated that EF and EC are indeed overlapping and highly similar constructs. Therefore, our results show that measures of EC and EF have substantial overlap in preschoolers and suggest an integrated model of self-regulation.

Altered theta-beta ratio in infancy associates with family history of ADHD and later ADHD-relevant temperamental traits

BACKGROUND

Uncovering the neural mechanisms that underlie symptoms of attention deficit hyperactivity disorder (ADHD) requires studying brain development prior to the emergence of behavioural difficulties. One new approach to this is prospective studies of infants with an elevated likelihood of developing ADHD.

METHODS

We used a prospective design to examine an oscillatory electroencephalography profile that has been widely studied in both children and adults with ADHD - the balance between lower and higher frequencies operationalised as the theta-beta ratio (TBR). In the present study, we examined TBR in 136 10-month-old infants (72 male and 64 female) with/without an elevated likelihood of developing ADHD and/or a comparison disorder (Autism Spectrum Disorder; ASD).

RESULTS

Infants with a first-degree relative with ADHD demonstrated lower TBR than infants without a first-degree relative with ADHD. Further, lower TBR at 10 months was positively associated with temperament dimensions conceptually related to ADHD at 2 years. TBR was not altered in infants with a family history of ASD.

CONCLUSIONS

This is the first demonstration that alterations in TBR are present prior to behavioural symptoms of ADHD. However, these alterations manifest differently than those sometimes observed in older children with an ADHD diagnosis. Importantly, altered TBR was not seen in infants at elevated likelihood of developing ASD, suggesting a degree of specificity to ADHD. Taken together, these findings demonstrate that there are brain changes associated with a family history of ADHD observable in the first year of life.

Treatment Response among Preschoolers with Disruptive Behavior Disorders: The Role of Temperament and Parenting

Objective: This study examined associations between temperament (negative affect, effortful control, and surgency) and symptoms of attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) within a diverse preschool sample. Interactions between temperament and parenting in the prediction of ADHD/ODD symptoms before and after an 8-week early intervention program (i.e., Summer Treatment Program for Pre-kindergartners; STP-PreK) were also examined.Method: The sample included 215 children (Mage = 5.0, 80.9% male, 84.7% Latinx) with a diagnosis of ADHD and/or ODD who completed the STP-PreK. Temperament was measured via parent report while ADHD/ODD symptoms were assessed via combination of parent and teacher report. Positive and negative parenting were assessed via rating scales and a standardized parent-child interaction observation.Results: Higher surgency was associated with greater symptom severity of ADHD/ODD pre- and post-treatment. Higher negative affect was associated with greater symptom severity of ODD pre- and post-treatment, while higher effortful control was only associated with lower symptom severity of inattention pre-treatment. Positive parenting predicted lower symptom severity of ADHD/ODD post-treatment. Moderation analyses indicated that the benefits of low levels of negative parenting only occurred when paired with low temperament risk for symptoms of hyperactivity and ODD. Additionally, only the combination of high surgency and high observed negative parenting resulted in greater symptom severity of ODD. Finally, decreases in inconsistent discipline predicted decreases across all symptom domains post-treatment.Conclusions: Our findings add to the temperament-based model of ADHD/ODD by highlighting temperament's unique prediction of treatment response as well as important interactions with the caregiving environment.

Attention-deficit hyperactivity disorder and executive dysfunction in preschool children. A comparison of NEPSY and BRIEF-P assessments

OBJECTIVE

The aim of the study was to explore prevalence, interrelations and accuracy of assessing psychopathology, intelligence, and executive functions (EF) in preschool children with ADHD (age 2.1-6.5 years).

METHOD

We prospectively investigated 115 preschool outpatient children (91 boys, 24 girls, aged 4.3±1.0 years) with the clinical diagnosis of ADHD. Assessment included clinical history, background, psychosocial problems (CBCL, C-TRF), ADHD (DISYPS external ratings), cognitive performance (WPPSI-III, K-ABC), and executive functions (BRIEF-P, NEPSY).

RESULTS

We found a high frequency of dysexecutive problems in up to 64 % in the parental BRIEF-P assessments, up to 62 % in the BRIEF-P teachers' assessments, and 62 % in the NEPSY functional assessments. Parental and teachers' BRIEF-P scores were only correlated in one subscale, inhibition, and NEPSY and BRIEF-P were not correlated at all. It was found that 42.5 % of the children with noticeable findings had agreeing results in all three, and another 45 % in two tests.

CONCLUSIONS

About 2/3 of the ADHD preschool children had detectable EF dysfunctions. In order to assess dysexecutive problems, multi-method testing is mandatory.