Comorbidity between ADHD and obesity: exploring shared mechanisms and clinical implications

Attention-deficit/hyperactivity disorder and obesity in US males and females, age 8-15 years: National Health and Nutrition Examination Survey 2001-2004

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Youth with ADHD may be at increased risk for obesity. Medications used to treat ADHD can affect weight. Few studies have investigated possible gender differences in associations between ADHD and obesity.

WHAT THIS STUDY ADDS

Nationally representative of US youth aged 8-15 years. Height and weight were measured, and ADHD assessed by structured diagnostic interview and parent report. Associations between ADHD and obesity are reported for males and females to enable gender comparisons.

OBJECTIVE

To investigate how associations between attention-deficit/hyperactivity disorder (ADHD) and obesity differ by gender and medication use in a nationally representative sample of US youth in which height and weight were measured.

METHODS

Youth age 8-15 (n = 3050) studied in the National Health and Nutrition Examination Survey 2001-2004. Obesity was defined as ≥95th percentile of US body mass index-for-age reference. ADHD was determined by asking parents if child had been diagnosed and using the Diagnostic Interview Schedule for Children IV. Gender-stratified multivariable logistic regression was used to estimate odds of obesity for youth with ADHD (medicated and unmedicated) relative to youth without ADHD.

RESULTS

Males with ADHD who were medicated had lower odds of obesity compared to males without ADHD (adjusted odds ratio [OR] = 0.42, 95% confidence interval [CI] = 0.23-0.78). Unmedicated males with ADHD were as likely as males without ADHD to be obese (adjusted OR = 1.02, 95% CI = 0.43-2.42). The odds of obesity for females taking medication for ADHD did not differ statistically from those of females without ADHD (adjusted OR = 1.21, 95% CI = 0.52-2.81). Females with ADHD not taking medication had odds of obesity 1.54 times those of females without ADHD; however, the 95% CI (0.79-2.98) was wide and not statistically significant at α = 0.05.

CONCLUSIONS

Associations between ADHD and obesity are influenced by treatment of ADHD with medication and may differ by gender. Youth with ADHD who are not treated with medication are as or more likely than youth without ADHD to be obese.

Attention-deficit/hyperactivity disorder and impairment in executive functions: a barrier to weight loss in individuals with obesity?

BACKGROUND

An increasing body of research points to a significant association of obesity to Attention-Deficit/Hyperactivity Disorder (ADHD) and deficits in executive functions. There is also preliminary evidence suggesting that children with ADHD may be at risk of obesity in adulthood.

DISCUSSION

In this article, we discuss the evidence showing that ADHD and/or deficits in executive functions are a barrier to a successful weight control in individuals enrolled in weight loss programs. Impairing symptoms of ADHD or deficits in executive functions may foster dysregulated eating behaviors, such as binge eating, emotionally-induced eating or eating in the absence of hunger, which, in turn, may contribute to unsuccessful weight loss. ADHD-related behaviors or neurocognitive impairment may also hamper a regular and structured physical activity. There is initial research showing that treatment of comorbid ADHD and executive functions training significantly improve the outcome of obesity in individuals with comorbid ADHD or impairment in executive functions.

SUMMARY

Preliminary evidence suggests that comorbid ADHD and deficits in executive functions are a barrier to a successful weight loss in individuals involved in obesity treatment programs. If further methodologically sound evidence confirms this relationship, screening and effectively managing comorbid ADHD and/or executive functions deficits in individuals with obesity might have the potential to reduce not only the burden of ADHD but also the obesity epidemics.

ADHD is a risk factor for overweight and obesity in children

OBJECTIVE

Although hyperactivity would seem to increase energy expenditure, attention-deficit hyperactivity disorder (ADHD) appears to increase the risk for being overweight. This study examined the body mass index (BMI) in children with ADHD and its relationship with age, gender, ADHD and comorbid symptom severity, inhibitory control, developmental coordination disorder, sleep duration, and methylphenidate use.

METHOD

Participants were 372 Dutch children with ADHD combined type aged 5 to 17 years participating in the International Multicenter ADHD Genetics (IMAGE) study. We categorized BMI according to international age- and gender-specific reference values and calculated BMI-standard deviation scores (BMI-SDS). The control population was matched for age, gender, and ethnicity and originated from the same birth cohort as the ADHD group. Inhibitory control was measured by the computerized Stop-signal task. Prevalence differences of underweight, overweight, and obesity between groups were expressed in odds ratios. We used linear regression analyses with gender, age, parent- and teacher-rated ADHD and comorbid scores, inhibitory control, sleep duration, motor coordination, and methylphenidate use to predict BMI-SDS.

RESULTS

Boys with ADHD aged 10 to 17 years and girls aged 10 to 12 years were more likely to be overweight than children in the general Dutch population. Younger girls and female teenagers, however, seemed to be at lower risk for being overweight. Higher oppositional behavior and social communication problems related to higher BMI-SDS scores, whereas more stereotyped behaviors related to lower BMI-SDS scores. We found no effects of the other examined associated risk factors on BMI-SDS.

CONCLUSIONS

Attention-deficit hyperactivity disorder in boys is a risk factor for overweight. In girls with ADHD, the prevalence of overweight is age dependent and most pronounced in girls aged 10 to 12 years. They have a 4-fold risk of being obese. Higher oppositional and social communication problems pose an increased risk for overweight, whereas sleep duration, motor coordination problems, and methylphenidate use do not.

Methylphenidate prevents high-fat diet (HFD)-induced learning/memory impairment in juvenile mice

The prevalence of childhood obesity has risen dramatically and coincident with this upsurge is a growth in adverse childhood psychological conditions including impulsivity, depression, anxiety and attention deficit/hyperactive disorder (ADHD). Due to confounds that exist when determining causality of childhood behavioral perturbations, controversy remains as to whether overnutrition and/or childhood obesity is important. Therefore, we examined juvenile mice to determine if biobehaviors were impacted by a short-term feeding (1-3wks) of a high-fat diet (HFD). After 1wk of a HFD feeding, mouse burrowing and spontaneous wheel running were increased while mouse exploration of the open quadrants of a zero maze, perfect alternations in a Y-maze and recognition of a novel object were impaired. Examination of mouse cortex, hippocampus and hypothalamus for dopamine and its metabolites demonstrated increased homovanillic acid (HVA) concentrations in the hippocampus and cortex that were associated with decreased cortical BDNF gene expression. In contrast, pro-inflammatory cytokine gene transcripts and serum IL-1α, IL-1β, TNF-α and IL-6 were unaffected by the short-term HFD feeding. Administration to mice of the psychostimulant methylphenidate prevented HFD-dependent impairment of learning/memory. HFD learning/memory impairment was not inhibited by the anti-depressants desipramine or reboxetine nor was it blocked in IDO or IL-1R1 knockout mice. In sum, a HFD rapidly impacts dopamine metabolism in the brain appearing to trigger anxiety-like behaviors and learning/memory impairments prior to the onset of weight gain and/or pre-diabetes. Thus, overnutrition due to fats may be central to childhood psychological perturbations such as anxiety and ADHD.

The role of impulsivity, inattention and comorbid ADHD in patients with bulimia nervosa

Introduction

Little is known about the contribution of impulsivity, inattention and comorbid attention deficit/hyperactivity disorder (ADHD) in the development and maintenance of bulimia nervosa (BN). In particular, their specific contribution to disordered eating symptoms and whether they have additive effects to the general psychopathological burden remains unclear.

Methods

Fifty-seven female patients seeking treatment for BN and 40 healthy controls completed diagnostic questionnaires and interviews that investigated: a) ADHD, b) impulsivity, c) eating disorders and d) general psychopathology. Attentional processes and impulsivity were assessed by a comprehensive computer-based neuropsychological battery.

Results

Twenty-one percent of patients with BN met the clinical cut-off for previous childhood ADHD compared to 2.5% of healthy controls. Adult ADHD according to DSM IV was also more prevalent in patients with BN, with an odds ratio of 4.2. Patients with BN and previous childhood ADHD were more impulsive and inattentive than patients with BN alone. These patients also displayed more severely disordered eating patterns and more general psychopathological symptoms compared with those without ADHD. Severity of eating disorder symptoms was better explained by inattentiveness than by either impulsivity or hyperactivity.

Discussion

Our data suggest an elevated rate of former childhood and current ADHD-symptoms in treatment-seeking patients with BN. Stronger impulsivity and inattention associated with more severe neuropsychological deficits and eating disorder symptoms indicate an additive risk that is clinically relevant for these patients. Thus, clinicians should identify comorbid patients who might profit from additional ADHD-specific treatments.

Prevalence of obesity and overweight among Chinese children with attention deficit hyperactivity disorder: a survey in Zhejiang Province, China

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is often comorbid with psychiatric and developmental disorders. This study aimed to investigate the prevalence of obesity and overweight among Chinese children with ADHD, and to explore which subtypes of the disorder may specifically be associated with obesity/overweight.

METHODS

Children meeting the DSM-IV criteria for ADHD were enrolled in the study. Weight, weight z-score, height, height z-score, BMI, and BMI z-score were used to evaluate growth status. Obesity and overweight were determined using the National Growth Reference for Chinese Children and Adolescents. Relations between the prevalence of obesity/overweight and different ADHD subtypes and pubertal development were analyzed.

RESULTS

A total of 158 children with ADHD (mean age: 9.2 years) were recruited for the study. The prevalences of obesity, overweight, and combined obesity/overweight were 12.0%, 17.1%, and 29.1%, respectively, which were significantly higher than in the general Chinese population (2.1%, 4.5%, and 6.6%, respectively). Multivariable analysis showed that the children with the combined subtype of ADHD and the onset of puberty were at a higher risk of becoming obese or overweight.

CONCLUSIONS

The prevalence of obesity in Chinese children with ADHD is higher than that of the general population. Children with the ADHD combined subtype who were at the onset of puberty were more likely to be overweight or obese.

Psychiatric disorders of patients seeking obesity treatment

BACKGROUND

Obese and overweight people have a higher risk of both chronic physical illness and mental illness. Obesity is reported to be positively associated with psychiatric disorders, especially in people who seek obesity treatment. At the same time, obesity treatment may be influenced by psychological factors or personality characteristics. This study aimed to understand the prevalence of mental disorders among ethnic Chinese who sought obesity treatment.

METHODS

Subjects were retrospectively recruited from an obesity treatment center in Taiwan. The obesity treatments included bariatric surgery and non-surgery treatment. All subjects underwent a standardized clinical evaluation with two questionnaires and a psychiatric referral when needed. The psychiatric diagnosis was made thorough psychiatric clinic interviews using the SCID. A total of 841 patients were recruited. We compared the difference in psychiatric disorder prevalence between patients with surgical and non-surgical treatment.

RESULTS

Of the 841 patients, 42% had at least one psychiatric disorder. Mood disorders, anxiety disorders and eating disorders were the most prevalent categories of psychiatric disorders. Females had more mood disorders and eating disorders than males. The surgical group had more binge-eating disorder, adjustment disorder, and sleep disorders than the non-surgical group.

CONCLUSION

A high prevalence of psychiatric disorders was found among ethnic Chinese seeking obesity treatment. This is consistent with study results in the US and Europe.

Attention-deficit/hyperactivity disorder and adverse health outcomes

Attention-deficit/hyperactivity disorder (ADHD) is defined by extreme levels of inattention-disorganization and/or hyperactivity-impulsivity. In DSM-IV, the diagnostic criteria required impairment in social, academic, or occupational functioning. With DSM-5 publication imminent in 2013, further evaluation of impairment in ADHD is timely. This article reviews the current state of knowledge on health-related impairments of ADHD, including smoking, drug abuse, accidental injury, sleep, obesity, hypertension, diabetes, and suicidal behavior. It concludes by suggesting the need for new avenues of research on mechanisms of association and the potential for ADHD to be an early warning sign for secondary prevention of some poor health outcomes.

Attention deficit hyperactivity disorder increases the risk of having abnormal eating behaviours in obese adults

OBJECTIVE

To determine the rate of abnormal eating behaviours in obese adult patients with attention deficit hyperactivity disorder (ADHD) in comparison with obese adult patients without ADHD.

METHOD

This case-control study includes: obese adult patients defined by a body mass index (BMI) ≥30 kg/m², screening positive in the adult ADHD self-report scale-V1.1. (ASRS-V1.1), attending the Nutrition Section, as cases; and obese adult patients screening negative, as controls. Weight, height and BMI were determined in all the participants. The rate of abnormal eating behaviours was determined using an eating pattern questionnaire.

RESULTS

Forty-five out of 51 (88.2%) cases vs 127 out of 179 (70.9%) controls had abnormal eating behaviours (p=0.01). Eating between-meal snacks was found in 39 (76.5%) cases vs 107 (59.8%) controls (p=0.03), going on binge eating episodes in 28 (54.9%) vs 42 (23.5%) (p=0.00), waking up at night to eat in 11 (21.6%) vs 16 (8.9%) (p=0.01), eating large amounts of food in 13 (25.5%) vs 38 (21.2%) (p=0.52), and eating in secret in 11 (21.6%) vs 16 (8.9%) (p=0.01), respectively.

CONCLUSION

This is the first study that determines the rate of these abnormal eating behaviours in obese adult patients with ADHD in comparison with obese adult patients without ADHD. A high rate of abnormal eating behaviours was observed in obese patients with ADHD. Our results suggest that ADHD is a risk factor for the development of these abnormal eating behaviours, which may be contributing factors of obesity and the unsuccessful treatment of obese patients.

Future directions in ADHD etiology research

Reviews salient emerging themes in the scientific literature related to identifying etiology and pathophysiology of ADHD. While bypassing the need for new treatment research, the review highlights three themes. First, recognition of the epigenetic effects is expected to revitalize the search for and mapping of early environmental influences on the development of ADHD. Second, neurobiological findings will have limited impact if not examined in the context of significant race and cultural variation in ADHD-related developmental processes, and in the context of rapidly changing social and technological contexts of children's development worldwide. Third, further examination of the phenotype and characterization of its dimensional and categorical structure remains a major need. Overall, the coming decades of etiology research on ADHD will be expected to capitalize on new scientific tools. The hope in the field is that new insights into fundamental prevention can emerge.

Factors associated with attention deficit/hyperactivity disorder among US children: results from a national survey

Background

The purpose of this study was to investigate the association between Attention Deficit/Hyperactivity Disorder (ADHD) and various factors using a representative sample of US children in a comprehensive manner. This includes variables that have not been previously studied such as watching TV/playing video games, computer usage, family member’s smoking, and participation in sports.

Methods

This was a cross-sectional study of 68,634 children, 5–17 years old, from the National Survey of Children’s Health (NSCH, 2007–2008). We performed bivariate and multivariate logistic regression analyses with ADHD classification as the response variable and the following explanatory variables: sex, race, depression, anxiety, body mass index, healthcare coverage, family structure, socio-economic status, family members’ smoking status, education, computer usage, watching television (TV)/playing video games, participation in sports, and participation in clubs/organizations.

Results

Approximately 10% of the sample was classified as having ADHD. We found depression, anxiety, healthcare coverage, and male sex of child to have increased odds of being diagnosed with ADHD. One of the salient features of this study was observing a significant association between ADHD and variables such as TV usage, participation in sports, two-parent family structure, and family members’ smoking status. Obesity was not found to be significantly associated with ADHD, contrary to some previous studies.

Conclusions

The current study uncovered several factors associated with ADHD at the national level, including some that have not been studied earlier in such a setting. However, we caution that due to the cross-sectional and observational nature of the data, a cause and effect relationship between ADHD and the associated factors can not be deduced from this study. Future research on ADHD should take into consideration these factors, preferably through a longitudinal study design.

Laboratory snack food intake, negative mood, and impulsivity in youth with ADHD symptoms and episodes of loss of control eating. Where is the missing link?

To compare laboratory food intake, negative mood and trait impulsivity and their association with attention deficit hyperactivity disorder (ADHD) and loss of control (LOC) eating in youth (middle childhood to early adolescence). Ninety 10-14 year old youths with symptoms of ADHD, symptoms of LOC eating, and control participants took part in a laboratory snack food meal after having rated trait impulsivity. Negative mood was self-reported pre and post snack food meal, while representativeness of eating behavior and liking of the food was assessed post laboratory snack food meal. The ADHD group consumed more snack food than the other groups. Food intake was not influenced by negative mood or trait impulsivity. All groups exhibited a decrease in negative mood from pre to post food intake that was not accounted for by level of hunger or liking of the food. The greater food intake of the ADHD group compared to the other groups may contribute to the development of overweight and therefore be in accordance with the high co-morbidity reported between ADHD and obesity in youth. The influence of impulsivity and negative mood on food intake could not be shown, which corroborates a recent review on the association of negative mood and bingeing in adults but needs further assessment, particularly in the younger age groups.

Examining the relationship between attention-deficit/hyperactivity disorder and overweight in children and adolescents

Although a higher prevalence of overweight/obesity was reported in clinical samples of patients with Attention-Deficit/Hyperactivity Disorder (ADHD), an association between overweight and ADHD has yet not been established in the general population in childhood. As both disorders are common and significantly affect psychosocial functioning, we investigated the prevalence of ADHD in overweight/obese youth and vice versa. In a cross-sectional nationally representative and community based survey 2,863 parents and their children aged 11-17 years rated symptoms on the Diagnostic and Statistical Manual of Mental Disorders-based German ADHD Rating scale. Weight and height were assessed by professionals. Body mass index was categorized according to national age and sex specific reference values. Overall, 4.2% of the respondents met criteria for ADHD. The prevalence of ADHD was significantly higher for overweight/obese (7%) than for normal weight (3.5%) and underweight (4.9%) children. In a logistic regression analysis controlling for age, gender, and socio-economic status, overweight/obese children were twice as likely to have an ADHD diagnosis (OR = 2.0). Vice versa, adjusting for all covariates, children with ADHD had an OR of 1.9 for overweight/obesity status. For all weight-status groups, children with ADHD more frequently reported eating problems as compared to their non-clinical counterparts. Overweight/obese respondents with ADHD displayed the highest level of health services utilization. A clinician should be aware of the significant risk for a child with ADHD to become overweight and for an overweight child to have ADHD. Longitudinal studies are needed to better understand the mechanisms underlying the association between ADHD and overweight/obesity.

Co-occurring weight problems among children with attention deficit/hyperactivity disorder: the role of executive functioning

OBJECTIVE

To explore the link between pediatric obesity and attention deficit/hyperactivity disorder (ADHD) by examining whether executive functioning (EF) and medication status are associated with body mass index (BMI) and weight status in children with ADHD.

METHOD

Participants for this study included 80 children (mean age=10 years, 9 months) with a DSM-IV diagnosis of ADHD, confirmed by a comprehensive clinical diagnostic assessment. Children's EF was measured using three neuropsychological tests, and severity of ADHD symptoms and medication status were obtained from parent report. Children's height and weight were also measured during the visit using a wall-mounted stadiometer and a balance beam scale.

RESULTS

Children with ADHD who performed poorly on the neuropsychological battery had greater BMI z-scores, and were more likely to be classified as overweight/obese compared with children with ADHD who performed better on the neuropsychological battery. In addition, children with ADHD who were taking a stimulant medication had significantly lower BMI z-scores compared with children with ADHD who were not taking medication or who were taking a non-stimulant medication.

CONCLUSION

EF is more impaired among children with ADHD and co-occurring weight problems, highlighting the importance of self-regulation as a link between pediatric obesity and ADHD.

Differential patterns of disordered eating in subjects with ADHD and overweight

OBJECTIVES

Despite growing evidence for an association between overweight and attention-deficit/hyperactivity disorder (ADHD), still little is known about the mechanisms underlying this relationship.

METHODS

Within a two (no ADHD, ADHD) × two (normal weight, overweight) factorial design (n = 94) we tested disordered eating behaviour in a laboratory breakfast procedure as well as delay aversion (DA) in male children aged 7-15 years.

RESULTS

While children with ADHD tended to eat above the normal level particularly at the beginning of the meal, children with overweight tended to eat above the normal level throughout the whole meal. Furthermore, preference for immediately available food was predicted by parental ratings of inattention and neuropsychological measures of DA in overweight children, and by impulsivity in children with ADHD.

CONCLUSIONS

Our results suggest distinct neuropsychopathological pathways to abnormal eating in ADHD and overweight. Thus, children with overweight might benefit more from specialized treatment programmes that aim at improving attention functions while in children with ADHD the treatment should focus on impulsivity.