Testing the dual pathway model of ADHD in obesity: a pilot study

Overlap of eating disorders and neurodivergence: the role of inhibitory control

BACKGROUND

Difficulties with inhibitory control have been identified in eating disorders (EDs) and neurodevelopmental disorders (NDs; including attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder), and there appear to be parallels between the expression of these impairments. It is theorised that impairments in inhibitory control within NDs may represent a unique vulnerability for eating disorders (EDs), and this same mechanism may contribute to poorer treatment outcomes. This review seeks to determine the state of the literature concerning the role of inhibitory control in the overlap of EDs and neurodivergence.

METHOD

A scoping review was conducted to summarise extant research, and to identify gaps in the existing knowledge base. Scopus, Medline, PsycInfo, Embase, and ProQuest were systematically searched. Studies were included if the study measured traits of ADHD or autism, and symptoms of ED, and required participants to complete a performance task measure of inhibitory control. Where studies included a cohort with both an ND and ED, these results had to be reported separately from cohorts with a singular diagnosis. Studies were required to be published in English, within the last 10 years.

RESULTS

No studies explored the relationship between autism and EDs using behavioural measures of inhibitory control. Four studies exploring the relationship between ADHD and EDs using behavioural measures of inhibitory control met selection criteria. These studies showed a multifaceted relationship between these conditions, with differences emerging between domains of inhibitory control. ADHD symptoms predicted poorer performance on measures of response inhibition in a non-clinical sample; this was not replicated in clinical samples, nor was there a significant association with EDs. Both ADHD and ED symptoms are associated with poor performance on attentional control measures; where these diagnoses were combined, performance was worse than for those with a singular diagnosis of ADHD. This was not replicated when compared to those with only ED diagnoses.

CONCLUSION

Impairments in attentional control may represent a unique vulnerability for the development of an ED and contribute to poor treatment outcomes. Further research is needed to explore the role of inhibitory control in EDs, ADHD and autism, including the use of both self-report and behavioural measures to capture the domains of inhibitory control.

Do executive functions differentiate Iranian children with attention-deficit/hyperactivity disorder with and without comorbid obesity?

OBJECTIVE

To compare multiple dimensions of executive function between children with attention-deficit/hyperactivity disorder (ADHD) with and without comorbid obesity.

METHOD

Participants were 90 Iranian children (ages 8-13, 50% female) who were equally dispersed across three study groups: typically developing (TD), ADHD with obesity (ADHD+O), and ADHD without obesity (ADHD-O). Study participants were administered a comprehensive battery of Iranian-adapted "cool" executive function tasks including Digit Span from the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V), Victoria Stroop Test (VST), Wisconsin Card Sorting Test (WCST), Tower of London, and dot-probe task (i.e., a task of attentional bias). Parents completed the Children's Scale for Future Thinking Questionnaire, which assesses future-oriented cognition (e.g., saving, planning, episodic foresight, delay of gratification), aligning more with "hot" executive functions. Groups were compared using multivariate and post-hoc univariate general linear models.

RESULTS

Significant group effects were observed for all executive function variables, broadly with the gradient pattern of TD > ADHD-O > ADHD+O. ADHD+O had poorer performances than ADHD-O for WISC-V Digit Span (d = -0.84), WCST Categories Completed (d = -0.55) and Perseverative Responses (d = 1.15), VST Interference Errors (d = 0.83) and Interference Time (d = 1.38), and Dot-Probe Task (d = 0.84). Relative to the ADHD-O group, ADHD+O had also poorer parent-reported Prospective Memory (d = -0.62), Episodic Foresight (d = -0.63), and Delay of Gratification (d = -0.54).

CONCLUSIONS

Children with ADHD-O have poorer executive functioning than those without obesity. We observed stronger effects for "cool" rather than "hot" domains of executive function, though this could be due to the former being performance-based and the latter parent-reported.

Self-control training supplementing inpatient multidisciplinary obesity treatment in children and adolescents

Research points to self-control as a possible mechanism for facilitating health behaviour and weight loss. The dual pathway model underpins the role of strong bottom-up reactivity towards food and weak top-down executive functions in obesity. Despite flourishing lab studies on attention bias modification or inhibition trainings, relatively few focused on training both processes to improve self-control in children and adolescents in inpatient multidisciplinary obesity treatment (MOT). Being part of the WELCOME project, this study investigated the effectiveness of Brain Fitness training (using the Dot Probe and Go/No-Go) as an adjunct to inpatient MOT in 131 Belgian children and adolescents. Changes in self-control (performance-based inhibitory control and attention bias as well as self-reported eating behaviour) in the experimental group were compared to sham training. Multiple Imputation was used to handle missing data. Inhibitory control and external eating improved over time (pre/post/follow-up), but we found no evidence for a significant interaction between time and condition. Future research should pay more attention to the role of individual variability in baseline self-control, sham training, and ecological validity of self-control training to improve real-life health behaviour and treatment perspectives for children and adolescents with weight problems.

Neurobehavioral phenotypes of delay discounting and cognitive control in child attention-deficit/hyperactivity disorder and obesity: Shared or distinct?

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) and obesity have been independently associated with deficient cognitive control (CC) and heightened preference for immediate reward.

OBJECTIVES

We aimed to identify specific shared and distinct neurobehavioral phenotypes of child obesity and ADHD by simultaneously measuring CC and preference for immediate reward in children with and without ADHD who varied in body weight.

METHODS

This case-control study included 323 8-12 year olds (ADHD n = 215, typically developing (TD) screened for ADHD symptoms [TD] controls n = 108) varying in body weight. Children completed a go/no-go task (assessing CC), as well as a classical money delay discounting (DD) task and novel experiential game time DD task (assessing preference for immediate over delayed rewards).

RESULTS

For game time DD, there was a body mass index z-score (BMIz)*ADHD interaction, such that TD children with overweight/obesity showed game time DD levels that were greater than those of TD children without overweight/obesity and similar to those of children with ADHD. Only children with ADHD showed poorer CC compared to TD children, with no effects of body weight.

CONCLUSIONS

Heightened game time DD with delays and rewards experienced in real-time may represent a neurobehavioral phenotype that is shared between ADHD and overweight/obesity in childhood, whereas deficient CC may be specific to children with ADHD.

ADHD in childhood predicts BMI and body composition measurements over time in a population-based birth cohort

BACKGROUND/OBJECTIVES

Obesity has been reported as an attention-deficit hyperactivity disorder (ADHD) comorbidity. So far, few studies have aimed to explore the potential causal relationship between ADHD and obesity, as well as used other measures of body composition like fat-free mass (FFM) and fat mass (FM) as measures of obesity. This study aimed to test the association between ADHD and body composition (body mass index [BMI] and others) and to evaluate the potential causal relationship with obesity.

SUBJECTS/METHODS

Data from the 1993 Pelotas (Brazil) birth cohort at age 11-, 15-, 18-, and 22-year follow-up was used. We performed a cross-lagged panel model (CLPM) analysis between ADHD symptoms and BMI to explore the causal relationship between both traits. Finally, we tested whether ADHD, inattention, and hyperactivity symptom scales were associated with BMI, FM, and FFM at 22 years.

RESULTS

In the CLPM, higher ADHD scores at age 11 predicted higher BMI at age 15 (β = 0.055, 95% CI [0.037; 0.073]). ADHD symptoms at age 11 was also associated with a decrease in the FFM (β = -0.16, 95% CI [-0.28; -0.05]), and an increase in the BMI (β = 0.17, 95% CI [0.10; 0.23]) and FM (β = 0.17, 95% CI [0.06; 0.29]) at 22 years. At 22 years of age, ADHD was associated with FFM and FM. Moreover, an increase in BMI was observed with an increase in several symptoms of ADHD in general (β = 0.06, 95% CI [0.004; 0.12]), and hyperactivity symptoms (β = 0.15, 95% CI [0.05; 0.25]).

CONCLUSION

ADHD at 11 years predicted a higher BMI at 15 years, and body fat composition in adulthood, suggesting higher scores on ADHD symptoms in early life may be a critical point for body composition in early adulthood. The hyperactivity symptoms may play an important role in the BMI increase.

Are Sensitivity to Punishment, Sensitivity to Reward and Effortful Control Transdiagnostic Mechanisms Underlying the Eating Disorder/Obesity Spectrum?

Although it has been postulated that eating disorders (EDs) and obesity form part of a broad spectrum of eating- and weight-related disorders, this has not yet been tested empirically. In the present study, we investigated interindividual differences in sensitivity to punishment, sensitivity to reward, and effortful control along the ED/obesity spectrum in women. We used data on 286 patients with eating disorders (44.6% AN-R, 24.12% AN-BP, and 31.82% BN), 126 healthy controls, and 640 Class II/III obese bariatric patients (32.81% Class II and 67.19% Class III) with and without binge eating. Participants completed the behavioral inhibition and behavioral activation scales, as well as the effortful control scale, to assess sensitivity to punishment and reward and effortful control. Results showed that patients with EDs scored significantly higher on punishment sensitivity (anxiety) compared to healthy controls and Class II/III obese patients; the different groups did not differ significantly on reward sensitivity. Patients with binge eating or compensatory behaviors scored significantly lower on effortful control than patients without binge eating. Differences in temperamental profiles along the ED/obesity spectrum appear continuous and gradual rather than categorical. This implies that it may be meaningful to include emotion regulation and impulse regulation training in the treatment of both EDs and obesity.

Obesity and ADHD: Exploring the role of body composition, BMI polygenic risk score, and reward system genes

The association between obesity and attention-deficit hyperactivity disorder (ADHD) has been extensively reported in the literature. However, the potential mechanisms underlying this association are not completely understood. This study aimed to evaluate the association between body composition and ADHD and explore the possible genetic mechanisms involved. We used data from the 1982 Pelotas (Brazil) Birth Cohort at age 30-year follow-up (N = 3630). We first used logistic regression analysis to test whether body mass index (BMI), fat mass (FM), and fat-free mass (FFM) were associated with ADHD. We further tested the association between BMI polygenic risk score (BMI-PRS) and ADHD and the role of the genes upregulated in the reward system using a gene-set association approach. BMI (odds ratio [OR] = 1.05; 95% confidence interval [CI], 1.00-1.09; p = 0.038) and FM (OR = 1.04; 95% CI, 1.00-1.07; p = 0.043) were associated with ADHD. The BMI-PRS was associated with ADHD (using p-value threshold (P_T) = 0.4; OR = 1.65; 95% CI, 1.02-2.65) at a nominal level. In gene-set analysis, the reward system genes were associated with BMI in subjects with a high BMI-PRS score, considering P_T = 0.4 (p = 0.014). The results suggest that BMI genetic components, especially those genes related to the reward system, may be involved in this association.

The Association between Executive Functions and Body Weight/BMI in Children and Adolescents with ADHD

Despite the increasing body of research on Attention Deficit Hyperactivity Disorder (ADHD), the results of the studies assessing the relationship between executive function deficit and the risk of obesity in people with ADHD are incongruent. Our study aimed to assess the relationship between measures of executive functions and body weight and Body Mass Index (BMI) in children and adolescents with ADHD and control subjects. The study group consisted of 58 subjects aged from 8 to 17 years with ADHD. The Control group consisted of 62 healthy age and sex-matched participants from primary and secondary schools. Weight, height, and BMI measurements were standardized. The Sustained Attention to Response Test (SART) and the Attention Network Test (ANT) were used to assess executive functions. Based on the analysis of the correlation and analysis of moderation, we found that subjects with higher weight in the study group presented a lower efficiency of the inhibition processes and gave more impulsive and incorrect answers. The occurrence of impulsive reactions might contribute to the risk of excessive weight in children and adolescents with ADHD.

Attention Deficit Hyperactivity Disorder: Association With Obesity and Eating Disorders

Attention deficit hyperactivity disorder (ADHD) is one of the most common treatable psychiatric illnesses that affect all age groups from children to adults. Most commonly it is diagnosed in childhood or during teenage years. It can affect the mental and physical health of an individual and disrupt normal academic, career, and social functioning. The quality of life of the individual is affected; thus if diagnosed and treated, the results are good. Obesity and eating disorders are one of the comorbidities associated with ADHD and can lead to various other health problems. This study was done to find out the association between ADHD, obesity, eating disorders, and the effect of medication. We collected data from various studies through multiple electronic databases such as PubMed and Google Scholar. We found 8610 relevant articles and finally narrowed it down to 30 using various criteria. An association was found between ADHD, obesity, and eating disorders, although the mechanism linking ADHD, obesity, and eating disorders still remains unclear according to most studies. Some studies say ADHD medication helps in losing gained weight; some say they do not affect the weight.

Negative Affectivity and Emotion Dysregulation as Mediators between ADHD and Disordered Eating: A Systematic Review

Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with disordered eating, especially addictive-like eating behavior (i.e., binge eating, food addiction, loss of control overeating). The exact mechanisms underlying this association are unclear. ADHD and addictive-like eating behavior are both associated with negative affectivity and emotion dysregulation, which we hypothesized are mediators of this relationship. The purpose of this systematic review was to review the evidence related to this hypothesis from studies assessing the relationship between childhood or adulthood ADHD symptomatology, negative affectivity, emotion dysregulation and addictive-like eating behavior. The systematic review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) recommendations. The literature search was conducted in PubMed and PsycINFO (publication date: January 2015 to August 2020; date of search: 2 September 2020). Out of 403 potentially relevant articles, 41 were retained; 38 publications reported that ADHD and disordered eating or addictive-like eating behavior were significantly associated, including 8 articles that suggested a mediator role of negative affectivity or emotion dysregulation. Sixteen publications reported that the association between ADHD symptomatology and disordered eating or addictive-like eating behavior differed according to gender, eating behavior and ADHD symptoms (hyperactivity, impulsivity and inattention). We discuss the practical implications of these findings and directions future research.

The Association between ADHD and Obesity: Intriguing, Progressively More Investigated, but Still Puzzling

This narrative review is aimed at presenting the most recent evidence on the association between attention-deficit/hyperactivity disorder (ADHD) and obesity. The review is informed by previous relevant systematic reviews and a search in Pubmed and PsycINFO up to 1 August 2019. Although the association between ADHD and obesity would seem, at first, paradoxical, in the past two decades there has been an increasing number of studies on this topic. The present review shows that there is meta-analytic evidence supporting a significant association between these two conditions, at least in adults. Growing evidence is also being published on the genetic and environmental factors underlying the association. However, the cause–effects paths, as well as the exact mechanisms explaining the association, remain unclear. Additionally, empirical evidence guiding the management/treatment of patients with the two conditions is still limited. Therefore, after almost 20 years from the first report of a link between ADHD and obesity, this association continues to be puzzling.

The Executive Functions in Overweight and Obesity: A Systematic Review of Neuropsychological Cross-Sectional and Longitudinal Studies

Background: The increasing incidence of people affected by overweight or obesity is a significant health problem. The knowledge of the factors which influences the inappropriate eating behaviors causing excessive body fat is an essential goal for the research. Overweight and obesity are significant risk factors for many health diseases, such as cardiovascular problems, diabetes. Recently, many studies have focused on the relationship between body weight and cognitive processes. Objectives: This systematic review is aimed to investigate the existence and the nature of the relationship between excessive body weight (overweight/obesity) and executive functions, analyzing cross-sectional, and longitudinal studies in order to verify the evidence of a possible causality between these variables. Methods: The review was carried out according to the PRISMA-Statement, through systematic searches in the scientific databases PubMed, Medline, PsychInfo, and PsycArticles. The studies selected examined performance on executive tasks by participants with overweight or obesity, aged between 5 and 70 years. Studies examining eating disorders or obesity resulting from other medical problems were excluded. Furthermore, the results of studies using a cross-sectional design and those using a longitudinal one were separately investigated. Results: Sixty-three cross-sectional studies and twenty-eight longitudinal studies that met our inclusion and exclusion criteria were analyzed. The results confirmed the presence of a relation between executive functions and overweight/obesity, although the directionality of this relation was not clear; nor did any single executive function emerge as being more involved than others in this relation. Despite this, there was evidence of a reciprocal influence between executive functions and overweight/obesity. Conclusions: This systematic review underlines the presence of a relationship between executive functions and overweight/obesity. Moreover, it seems to suggest a bidirectional trend in this relationship that could be the cause of the failure of interventions for weight reduction. The results of this review highlight the importance of a theoretical model able to consider all the main variables of interest, with the aim to structuring integrated approaches to solve the overweight/obesity problems.