Douglas Sjöwall

Multiple deficits in ADHD: executive dysfunction, delay aversion, reaction time variability, and emotional deficits

Background The notion that ADHD constitutes a heterogeneous disorder is well accepted. However, this study contributes with new important knowledge by examining independent effects of a large range of neuropsychological deficits. In addition, the study investigated whether deficits in emotional functioning constitute a dissociable component of ADHD. Method The study included children with ADHD (n = 102; 7–13 years) and a control sample individually matched with regard to age and gender. The administered tasks were designed to tap into three different neuropsychological domains: executive functions (i.e., working memory, inhibition, and shifting), delay aversion, and reaction time variability. Parent ratings of emotion regulation and a test of emotion recognition were also included. Results Children with ADHD differed significantly from controls on all measures, except for delay aversion and recognition of disgust. No main effects of gender or interaction effects of gender and group were found. More importantly, executive functioning, reaction time variability, and emotional functioning all contributed independently to distinguishing between children with ADHD and controls. Conclusions The current study supports the view of ADHD as a heterogeneous disorder related to multiple neuropsychological deficits. In addition, emotional functioning appears to be an area of importance for ADHD that needs to be incorporated into future theoretical models.

Neuropsychological deficits in preschool as predictors of ADHD symptoms and academic achievement in late adolescence

High levels of ADHD symptoms are related to severe negative outcomes, which underscore the importance of identifying early markers of these behavior problems. The main aim of the present study was therefore to investigate whether neuropsychological deficits in preschool are related to later ADHD symptoms and academic achievement, over and above the influence of early ADHD symptom levels. The present study is unique because it includes a broader range of predictors compared to previous studies and the participants are followed over time for as long as 13 years (i.e., ages 5–18 years). Preschool data included measures of executive functioning and reaction time variability as well as emotional reactivity and emotion regulation of both positive and negative emotions. When controlling for early ADHD symptom levels, working memory, reaction time variability, and regulation of happiness/exuberance were significantly related to inattention whereas regulation of happiness/exuberance and anger reactivity were significantly related to hyperactivity/impulsivity. Furthermore, working memory and reaction time variability in preschool were significantly related to academic achievement in late adolescence beyond the influence of early ADHD symptoms. These findings could suggest that it is possible to screen for early neuropsychological deficits and thereby identify children who are at risk of negative outcomes. Furthermore, our results suggest that interventions need to look beyond executive functioning deficits in ADHD and also target the role of emotional functioning and reaction time variability. The importance of including both the positive and negative aspects of emotional functioning and distinguishing between emotion regulation and emotional reactivity was also demonstrated.

Functional impairments in attention deficit hyperactivity disorder: the mediating role of neuropsychological functioning.

Attention deficit hyperactivity disorder (ADHD) is associated with multiple neuropsychological deficits and the present study aimed to investigate to what extent these deficits are related to the functional impairments associated with the disorder. The results showed that all executive functioning deficits and reaction time variability acted as mediators in the relation between ADHD and academic achievement. However, only the effect of working memory for language skills, and the effects of reaction time variability and working memory for mathematics, remained significant when studying independent effects. Regulation of anger was a significant mediator for peer problems. Gender or symptoms of oppositional defiant disorder (ODD) or conduct disorder (CD) did not moderate these findings.

Quick Delay Questionnaire: Reliability, validity, and relations to functional impairments in adults with attention-deficit/hyperactivity disorder (ADHD)

The Quick Delay Questionnaire (QDQ) is a self-report measure of delay-related behaviors in adults, and the present study aimed at investigating the psychometric properties of QDQ scores, how well they can discriminate between ADHD adults and both clinical and nonclinical controls, as well as their relations to measures of functional impairments. In the present study, QDQ ratings, a laboratory measure of delay discounting, and ratings of functional impairments were collected from adults diagnosed with attention-deficit/hyperactivity disorder (ADHD; n = 51), a clinical control group with other psychiatric disorders (n = 46), and a nonclinical control group (n = 105). Results showed that the QDQ scores showed adequate reliability. Adults with ADHD had higher scores compared with normal controls on both QDQ subscales, and they also reported higher levels of delay aversion than the clinical controls. Logistic regression analyses showed high specificity but low sensitivity when trying to discriminate between adults with ADHD and nonclinical controls. QDQ scores were not associated with a laboratory measure of delay discounting, but with functional impairments such as substance use, criminality, and money management. Our findings indicate that QDQ scores are reliable, but this instrument should be regarded as a complement rather than as a replacement for laboratory measures. The relatively low sensitivity of QDQ scores is in line with current models of heterogeneity stating that only a subgroup of individuals with ADHD has high levels of delay-related behaviors. Our findings further indicate that this subgroup may be at particularly high risk for problems in everyday life.

A critical appraisal of the role of neuropsychological deficits in preschool ADHD

ABSTRACT The present study aimed at improving our understanding of the role of neuropsychological deficits in preschool Attention Deficit Hyperactivity Disorder (ADHD). The study included 52 children in the ADHD group and 72 controls (age 4–6 years). Both laboratory measures and teacher reports of executive deficits (i.e., working memory, inhibition, and shifting), delay-related behaviors (i.e., the preference for minimizing delay), and emotional functions (i.e., emotion recognition and regulation) were included. Variable-oriented analyses were complemented with person-oriented analyses (i.e., identifying the proportion of patients considered impaired). Results showed that the ADHD group differed from controls with regard to all measures of executive functioning and most measures of delay-related behaviors, but few differences were found for emotional functioning. A substantial subgroup (23%) of children with ADHD did not have a neuropsychological deficit in any domain. There were subgroups with executive or delay-related deficits only, but no pure emotional subgroup. The overlap between different neuropsychological deficits was much larger when teacher reports were used as opposed to laboratory measures. Regarding functional impairments, large mean differences were found between the ADHD group and controls. However, neuropsychological deficits were not able to explain individual variations in daily life functioning among children with ADHD. In conclusion, the present study identified some important methodological and theoretical issues regarding the role of neuropsychological functioning in preschool ADHD.