The role of impulsivity in pediatric obesity and weight status: A meta-analytic review

Brain structure, executive function and appetitive traits in adolescent obesity

BACKGROUND

Children with obesity show differences in brain structure, executive function and appetitive traits when compared with lean peers. Little is known on the relationship between brain structure and these traits.

OBJECTIVES

To investigate the relationship between differences in brain structure and executive function and appetitive traits, in obese and lean adolescents.

METHODS

MRI was used to measure cortical thickness and subcortical volumes. Executive function was measured by a Stop Signal-and a Choice Delay Task. Appetitive traits were measured using the Child Eating Behaviour Questionnaire.

RESULTS

Adolescents with obesity had greater volumes of the pallidum; 1.78 mL (SE 0.03, p=0.014), when compared with controls; 1.65 mL (SE 0.02). In the group with obesity, greater pallidum volume was positively associated with the ability to delay reward in the Choice Delay Task (p=0.012).

CONCLUSION

The association between pallidum volumes and Choice Delay Task in obese adolescents supports the hypothesis that the pallidum plays an important role in executive dysfunction in obese children.

Improving Self-Regulation for Obesity Prevention in Head Start: A Randomized Controlled Trial

OBJECTIVES

To determine the effect of an intervention to improve emotional and behavioral self-regulation in combination with an obesity-prevention program on the prevalence of obesity and obesity-related behaviors in preschoolers.

METHODS

This was a cluster-randomized intervention trial in Head Start (HS) classrooms conducted in each of 4 academic years from 2011 to 2015. Participants (697 children; 49% boys; mean age: 4.1 ± 0.5 years; 48% white, 30% African American, 12% Hispanic) were randomly assigned by classroom to 1 of 3 intervention arms: (1) HS + Preschool Obesity Prevention Series (POPS) + Incredible Years Series (IYS) (HS enhanced by the POPS [program targeting evidence-based obesity-prevention behaviors] and the IYS [program to improve children's self-regulation]), (2) HS+POPS, or (3) HS. Primary outcomes were changes in prevalence of obesity, overweight/obesity, BMI z score, and teacher-reported child emotional and behavioral self-regulation; secondary outcomes were dietary intake, outdoor play, screen time, and parent nutrition knowledge and nutrition self-efficacy.

RESULTS

HS+POPS+IYS improved teacher-reported self-regulation compared with HS+POPS (P < .001) and HS (P < .001), but there was no effect on the prevalence of obesity (16.4% preintervention to 14.3% postintervention in HS+POPS+IYS versus 17.3% to 14.4% in HS+POPS [P = .54] versus 12.2% to 13.0% in HS [P = .33]). There was no effect of HS+POPS compared with HS alone (P = .16). There was no effect on other outcomes except for sugar-sweetened beverage intake (HS+POPS+IYS resulted in a greater decline than HS; P = .005).

CONCLUSIONS

An intervention for parents and children to improve HS preschoolers' emotional and behavioral self-regulation in combination with an obesity-prevention curriculum did not reduce obesity prevalence or most obesity-related behaviors.

Impulsivity as a moderator of the associations between child maltreatment types and body mass index

Child maltreatment has emerged as an important risk factor for adult obesity (Danese & Tan, 2014; Hemmingsson et al., 2014). However, there is a need for research delineating the factors that play a role in this association. Impulsivity has been shown to be associated with both child maltreatment (Brodsky et al., 2001) and body mass index (BMI; Cortese et al., 2008; Thamotharan et al., 2013). Further, given previous research showing that adverse events interact with impulsivity to predict hazardous drinking behaviors (Fox et al., 2010), there is reason to hypothesize that child maltreatment might interact with impulsivity to predict other adverse health outcomes, such as elevated BMI. Accordingly, the current study examined whether impulsivity moderated the association between child maltreatment types (i.e., physical abuse, physical neglect, sexual abuse, emotional abuse, and emotional neglect) and BMI. The sample was comprised of 500 undergraduate students (49.6% male) between the ages of 18 and 25 years. Regression analyses suggested that maltreatment types and impulsivity were not uniquely associated with BMI. However, impulsivity moderated the association between childhood sexual abuse and adult BMI, such that BMI was highest at high levels of both sexual abuse and impulsivity. Impulsivity did not moderate the associations between the other child maltreatment types and BMI. Limitations, future directions, and clinical implications of this research are discussed.

The association of self-regulation with weight loss maintenance after an intensive combined lifestyle intervention for children and adolescents with severe obesity

BACKGROUND

Knowledge is limited on the role the ability to self-regulate plays in the long-term outcome of obesity treatment in children and adolescents with severe obesity. The purpose of this study was to determine whether the ability to self-regulate after an one year intensive, partly inpatient, combined lifestyle intervention is associated with weight loss maintenance in children and adolescents with severe obesity.

METHODS

One hundred twenty participants (8-19 years) with an average SDS-BMI of 3.41 and their parents/caregivers were included in an intervention study. As primary determinant of weight loss maintenance, general self-regulation ability was evaluated using two behavioral computer tasks assessing inhibitory control and sensitivity to reward.

RESULTS

There was no association between inhibitory control at T12 and ∆SDS-BMI between T12 and T24 (β = 0.0002; CI 95% = -0.0010-0.0014; P = 0.761). There was also no relation between sensitivity to reward at T12 and ∆SDS-BMI between T12 and T24 (β = -0.0028; CI 95% = -0.0075-0.0019; P = 0.244). None of the psychosocial factors that were examined as moderators, showed a statistically significant interaction, except for parental feeding style (P = 0.023).

CONCLUSIONS

The ability to self-regulate after an intensive, partly inpatient, multidisciplinary one year intervention for severe obesity in children and adolescents was not associated with the ability to maintain the achieved weight loss during the following year. Factors that explain the large range of long term outcomes need to be elucidated.

TRIAL REGISTRATION

Netherlands Trial Register (NTR1678, registered 20-Feb-2009).

Not so fast: The impact of impulsivity on weight loss varies by treatment type

Behavioral weight loss (BWL) treatments result in suboptimal weight losses for many individuals. Impulsivity appears to be a maintenance factor of obesity, yet few studies have examined impulsivity as a predictor of outcomes from BWL. We examined specific facets of impulsivity (inhibitory control and delay discounting) as moderators of outcome in BWL. Overweight adults (n = 190) were randomized to standard behavioral treatment (SBT) or acceptance-based behavioral treatment (ABT). We hypothesized that impulsivity would be inversely associated with weight loss, and that the association between impulsivity and outcome would be attenuated in the ABT condition. Poorer general inhibitory control predicted lower percent weight lost at 12 months across conditions at the trend level (b = -0.003, p = 0.06). The negative impact of low inhibitory control on weight loss was attenuated by assignment to ABT versus SBT (b = 0.004, p = 0.03). Treatment condition, at trend level, also moderated the impact of delay discounting (b = -0.011, p = .098) and food-specific inhibitory control (b = 0.003, p = 0.06) on percent weight loss such that those with greater impulsivity benefitted most from ABT. Results reveal a potential pattern that impulsivity reduces benefit derived from SBT but not ABT. Further research on the moderating effect of impulsivity is necessary to inform the development of targeted treatments for clinically meaningful subtypes of patients.

Cardiac autonomic regulation as a predictor for childhood obesity intervention success

Childhood obesity is a major public health concern; behavioural interventions induce weight reduction in some, but success is variable. Heart rate variability (HRV) has been associated with impulse control and extent of dieting success. This study investigated the relationship between HRV and post childhood obesity intervention weight-management success, and involved recording the frequency-domain HRV measures ratio between low frequency and high frequency power (LF/HF) and high frequency power (HF), and the time-domain measure, percentage of successive beat-to-beat intervals that differ by more than 50ms (PNN50). It was expected that greater LF/HF and lower HF would be associated with greater post-intervention weight gain, and that greater PNN50 would be associated with greater impulse control. Seventy-four participants aged 9-14 (M=10.7; s.d.: 1.1) attended a weight-management camp, where HRV was recorded. Stop signal reaction time (SSRT) was also recorded as a measure of impulse control. As expected, SSRT was positively associated with pre-intervention body mass (r=0.301, P=0.010) and negatively associated with PNN50 (β=0.29, P=0.031). Post-intervention body mass change was positively associated with LF/HF (β=0.34, P=0.037), but was not associated with HF. Lifestyle interventions may have a greater chance of effectively supporting long-term weight-management for children with lower LF/HF; assessing HRV of obese children may be helpful in informing obesity treatment decisions.

Overweight in adolescent, psychiatric inpatients: A problem of general or food-specific impulsivity?

Adolescent psychiatric patients are vulnerable to weight problems and show an overrepresentation of overweight compared to the healthy population. One potential factor that can contribute to the etiology of overweight is higher impulsivity. As of yet, it is unclear whether it is a general impulse control deficit or weight-related aspects such as lower impulse control in response to food that have an impact on body weight. As this may have therapeutic implications, the current study investigated differences between overweight and non-overweight adolescent psychiatric inpatients (N = 98; aged 12-20) in relation to trait impulsivity and behavioral inhibition performance. The Barratt Impulsiveness Scale and two go/no-go paradigms with neutral and food-related stimulus materials were applied. Results indicated no significant differences concerning trait impulsivity, but revealed that overweight inpatients had significantly more difficulties in inhibition performance (i.e. they reacted more impulsively) in response to both food and neutral stimuli compared to non-overweight inpatients. Furthermore, no specific inhibition deficit for high-caloric vs. low-caloric food cues emerged in overweight inpatients, whereas non-overweight participants showed significantly lower inhibition skills in response to high-caloric than low-caloric food stimuli. The results highlight a rather general, non-food-specific reduced inhibition performance in an overweight adolescent psychiatric population. Further research is necessary to enhance the understanding of the role of impulsivity in terms of body weight status in this high-risk group of adolescent inpatients.

Observed self-regulation is associated with weight in low-income toddlers

Obesity emerges in early childhood and tracks across development. Self-regulation develops rapidly during the toddler years, yet few studies have examined toddlers' self-regulation in relation to concurrent child weight. Further, few studies compare child responses in food and non-food-related tasks. Our goal was to examine toddlers' observed behavioral and emotional self-regulation in food and non-food tasks in relation to their body mass index z-score (BMIz) and weight status (overweight/obese vs. not). Observational measures were used to assess self-regulation (SR) in four standardized tasks in 133 low-income children (M age = 33.1 months; SD = 0.6). Behavioral SR was measured by assessing how well the child could delay gratification for a snack (food-related task) and a gift (non-food-related task). Emotional SR was measured by assessing child intensity of negative affect in two tasks designed to elicit frustration: being shown, then denied a cookie (food-related) or a toy (non-food-related). Task order was counterbalanced. BMIz was measured. Bivariate correlations and regression analyses adjusting for child sex, child race/ethnicity, and maternal education were conducted to examine associations of SR with weight. Results were that better behavioral SR in the snack delay task associated with lower BMIz (β = -0.27, p < 0.05) and lower odds of overweight/obesity (OR = 0.66, 95% CI 0.45, 0.96), but behavioral SR in the gift task did not associate with BMIz or weight status. Better emotional SR in the non-food task associated with lower BMIz (β = -0.27, p < 0.05), and better emotional SR in food and non-food tasks associated with lower odds of overweight/obesity (OR = 0.65, 95% CI 0.45, 0.96 and OR = 0.56, 95% CI 0.37, 0.87, respectively). Results are discussed regarding how behavioral SR for food and overall emotional SR relate to weight during toddlerhood, and regarding early childhood obesity prevention implications.

Associations between parental impulsivity and child body mass index

Objective

The aim of this study was to examine the association between parental impulsivity and (12–15 year old) child body mass index (BMI).

Methods

In total, 300 parents completed a survey regarding their own impulsivity level (Barratt impulsiveness scale) and that of their child (impulsivity scale of the temperament in middle childhood questionnaire), and supplied details of their own and their child’s height and weight. Partial correlations were computed to assess relationships between both parental and child impulsiveness scores and child BMI z-scores, independent of parental BMI. Mediation analyses were performed to assess the potential mediating role of child impulsivity on the relationship between parental impulsivity and child BMI z-score.

Results

For daughters, parental impulsivity was significantly correlated with BMI z-score. Parent-reported child impulsivity was not related to child BMI z-score, and no evidence was found for a mediating effect of parent-reported child impulsivity on the relationship between parental impulsivity and child BMI z-score.

Conclusion

There is a stronger association between parental impulsivity and child BMI z-score than between child impulsivity and child BMI z-score. The relationship between parental impulsivity and-child BMI z-score could possibly be explained by parenting styles and practices. The potentially mediating role of parenting should be taken into account in future studies investigating the role of personality in children becoming overweight or obese.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3048-x) contains supplementary material, which is available to authorized users.

Task-Based and Questionnaire Measures of Inhibitory Control Are Differentially Affected by Acute Food Restriction and by Motivationally Salient Food Stimuli in Healthy Adults

Adaptive eating behaviors are dependent on an interaction between motivational states (e.g., hunger) and the ability to control one's own behavior (inhibitory control). Indeed, behavioral paradigms are emerging that seek to train inhibitory control to improve eating behavior. However, inhibitory control is a multifaceted concept, and it is not yet clear how different types (e.g., reactive motor inhibition, proactive motor inhibition, reward-related inhibition) are affected by hunger. Such knowledge will provide insight into the contexts in which behavioral training paradigms would be most effective. The present study explored the impact of promoting a "need" state (hunger) together with motivationally salient distracting stimuli (food/non-food images) on inhibitory control in 46 healthy adults. Participants attended two study sessions, once after eating breakfast as usual and once after acute food restriction on the morning of the session. In each session, participants completed questionnaires on hunger, mood and inhibitory control, and undertook task-based measures of inhibitory control, and had physiological measurements (height, weight, and blood glucose) obtained by a researcher. Acute food restriction influenced task-based assessments but not questionnaire measures of inhibitory control, suggesting that hunger affects observable behavioral control but not self-reported inhibitory control. After acute food restriction, participants showed greater temporal discounting (devaluation of future rewards), and subjective hunger and these were inversely correlated with stop accuracy on the stop signal task. Finally, participants generally responded faster when food-related distractor images were presented, compared to non-food images, independent of state. This suggests that although food stimuli motivate approach behavior, stimulus relevance does not impact inhibitory control in healthy individuals, nor interact with motivational state. These findings may provide some explanation for poorer inhibitory control often reported in studies of individuals who practice restraint over eating.

Popular Music Celebrity Endorsements in Food and Nonalcoholic Beverage Marketing

BACKGROUND

Food and beverage marketing has been associated with childhood obesity. We quantified the number and type of food or beverage brands promoted by music celebrities, assessed the nutritional quality of the products, and examined Teen Choice Award data to assess the celebrities' popularity among adolescents.

METHODS

This was a descriptive study. A list of music celebrities associated with the 2013 and 2014 Billboard Hot 100 Chart, which ranks songs according to sales and radio impressions, was compiled. Data on celebrity endorsements were gathered from official company Web sites, YouTube commercials, an advertising database, and media reports. Nutritional quality of foods was assessed according to the Nutrient Profile Index, whereas nonalcoholic beverages were evaluated based on calories from added sugar. Teen Choice Award nominations were used to measure the celebrities' popularity among adolescents.

RESULTS

Of the 590 endorsements made by the 163 celebrities in the sample, consumer goods (eg, fragrances, makeup) represented the largest endorsement category (26%), followed by food and beverage (18%) and retail (11%). Sixty-five celebrities were collectively associated with 57 different food and beverage brands owned by 38 parent companies. Of these 65 celebrities, 53 (81.5%) had ≥1 Teen Choice Award nomination. Forty-nine (71%) of the 69 nonalcoholic beverage references promoted sugar-sweetened beverages. Twenty-one (80.8%) of the 26 endorsed foods were energy dense and nutrient poor. Baauer, will.i.am, Justin Timberlake, Maroon 5, and Britney Spears had the most food and beverage endorsements.

CONCLUSIONS

This study demonstrates that music celebrities who are popular among adolescents endorse energy-dense, nutrient-poor products.

Influences on Healthy-Eating Decision Making in Latino Adolescent Children of Migrant and Seasonal Agricultural Workers

INTRODUCTION

Latino children demonstrate high rates of unhealthy weight, and children of Latino migrant and seasonal agricultural workers are heavier than their Latino peers.

METHOD

This one-group, cross-sectional, mixed-methods pilot study explored healthy-eating decision making with 12- to 14-year-olds recruited from a Midwest summer migrant education program. Demographics, decision-making, self-efficacy, and social support survey instruments were used, along with gender-specific focus groups.

RESULT

In the convenience sample, which included 24 participants, students felt varying degrees of uncertainty when choosing healthy foods in social situations, and 67% made poor-quality decisions. Parents offered greater support for healthy eating compared with friends. Qualitative analyses identified three themes: healthy decision making includes fruits, vegetables, and physical activity; mothers have influence over health and healthy decisions; and friends encourage unhealthy food choices.

DISCUSSION

Influences on healthy-eating decision making in Latino adolescent children of migrant and seasonal agricultural workers, which were previously missing from the literature, were identified. Future research includes development of interventions to assist these adolescents with healthy-eating decision making.

Examining weight concern and delay discounting in adolescent females

OBJECTIVE

Pediatric obesity is a growing public health concern that contributes to high rates of negative long-term physical and mental health outcomes. Research focused on identifying risk for pediatric obesity has linked delay discounting, or an inclination for immediate rewards, as well as weight concern to individuals with greater Body Mass Index (BMI). The current study seeks to fill a void in the literature by examining how these two variables interact to promote higher BMI in female adolescents.

METHOD

Adolescent (n=60) females between the ages of 13-19years (mage=17.45, SD=1.74) of age completed the Eating Disorder Examination Questionnaire (EDE-Q) and the Delay Discounting Questionnaire.

RESULTS

A mediation model examined whether delay discounting accounted for the relationship between weight concern and BMI. Results indicate that in the current study weight concern was negatively related to delay discounting and delay discounting was negatively related to BMI. The overall model revealed that a partial mediation occurred [b=1.28, t(60)=4.92, p<0.01].

DISCUSSION

These results suggest that while impulsivity is an important factor to consider, other constructs may also be influential in how weight concerns contribute to greater BMI. Nevertheless, the results indicate that prevention and interventions should identify females with high levels of both weight concern and impulsivity as an increased risk for experiencing pediatric obesity and long-term negative health outcomes.

A systematic review of the relationship between eating, weight and inhibitory control using the stop signal task

Altered inhibitory control (response inhibition, reward-based inhibition, cognitive inhibition, reversal learning) has been implicated in eating disorders (EDs) and obesity. It is unclear, however, how different types of inhibitory control contribute to eating and weight-control behaviours. This review evaluates the relationship between one aspect of inhibitory control (a reactive component of motor response inhibition measured by the stop signal task) and eating/weight in clinical and non-clinical populations. Sixty-two studies from 58 journal articles were included. Restrained eaters had diminished reactive inhibitory control compared to unrestrained eaters, and showed greatest benefit to their eating behaviour from manipulations of inhibitory control. Obese individuals may show less reactive inhibitory control but only in the context of food-specific inhibition or after executive resources are depleted. Of the limited studies in EDs, the majority found no impairment in reactive inhibitory control, although findings are inconsistent. Thus, altered reactive inhibitory control is related to some maladaptive eating behaviours, and hence may provide a therapeutic target for behavioural manipulations and/or neuromodulation. However, other types of inhibitory control may also contribute. Methodological and theoretical considerations are discussed.

Imbalance in Resting State Functional Connectivity is Associated with Eating Behaviors and Adiposity in Children

Background and Hypothesis

Over the past 30 years, childhood obesity in the US has nearly doubled, while obesity has tripled among adolescents. Non-homeostatic eating, influenced by impulsivity and inhibition, may undermine successful long-term weight loss. We hypothesized that unhealthy eating habits and adiposity among children are associated with functional connectivity between brain regions associated with impulsivity, response inhibition, and reward.

Methods

We analyzed resting state functional magnetic resonance images from 38 children, ages 8–13. Using seed-based resting state functional connectivity, we quantified connectivity between brain regions associated with response inhibition (inferior parietal lobe [IPL]), impulsivity (frontal pole), and reward (nucleus accumbens [NAc]). We assessed the relationship of resting state functional connectivity with adiposity, quantified by BMI z-score, and eating behaviors, as measured by the Child Eating Behaviour Questionnaire (CEBQ). We computed an imbalance measure—the difference between [frontal pole:NAC] and [ipl:nac] functional connectivity—and investigated the relationship of this imbalance with eating behaviors and adiposity.

Results

As functional connectivity imbalance is increasingly biased toward impulsivity, adiposity increases. Similarly, as impulsivity-biased imbalance increases, food approach behaviors increase and food avoidance behaviors decrease. Increased adiposity is associated with increased food approach behaviors and decreased food avoidance behaviors.

Conclusions

In the absence of any explicit eating-related stimuli, the developing brain is primed toward food approach and away from food avoidance behavior with increasing adiposity. Imbalance in resting state functional connectivity that is associated with non-homeostatic eating develops during childhood, as early as 8–13 years of age. Our results indicate the importance of identifying children at risk for obesity for earlier intervention. In addition to changing eating habits and physical activity, strategies that normalize neural functional connectivity imbalance are needed to maintain healthy weight. Mindfulness may be one such approach as it is associated with increased response inhibition and decreased impulsivity.

Reward-related decision making in eating and weight disorders: A systematic review and meta-analysis of the evidence from neuropsychological studies

Eating disorders (EDs) and overweight/obesity (OW/OB) are serious public health concerns that share common neuropsychological features and patterns of disturbed eating. Reward-related decision making as a basic neurocognitive function may trans-diagnostically underlie both pathological overeating and restricted eating. The present meta-analysis synthesizes the evidence from N=82 neuropsychological studies for altered reward-related decision making in all ED subtypes, OW and OB. The overall effect sizes for the differences between currently-ill ED patients and OW/OB people and controls were Hedge's g=-0.49 [CI: -0.63; -0.35], and Hedge's g=-0.39 [CI: -0.53; -0.25], respectively. Decision making was found to be altered to similar degrees in all ED subtypes and OB. Effect sizes, however, diverged for the different measures of decision making. Adolescents appear to be less affected than adults. When foods were used as rewarding stimuli, decision making was found to be intact in OB. The findings support that altered general reward-related decision making is a salient neuropsychological factor across eating and weight disorders in adulthood.

SRT-Joy - computer-assisted self-regulation training for obese children and adolescents: study protocol for a randomized controlled trial

Background

Obesity is not only a highly prevalent disease but also poses a considerable burden on children and their families. Evidence is increasing that a lack of self-regulation skills may play a role in the etiology and maintenance of obesity. Our goal with this currently ongoing trial is to examine whether training that focuses on the enhancement of self-regulation skills may increase the sustainability of a complex lifestyle intervention.

Methods/Design

In a multicenter, prospective, parallel group, randomized controlled superiority trial, 226 obese children and adolescents aged 8 to 16 years will be allocated either to a newly developed computer-training program to improve their self-regulation abilities or to a placebo control group. Randomization occurs centrally and blockwise at a 1:1 allocation ratio for each center. This study is performed in pediatric inpatient rehabilitation facilities specialized in the treatment of obesity. Observer-blind assessments of outcome variables take place at four times: at the beginning of the rehabilitation (pre), at the end of the training in the rehabilitation (post), and 6 and 12 months post-rehabilitation intervention. The primary outcome is the course of BMI-SDS over 1 year after the end of the inpatient rehabilitation. Secondary endpoints are the self-regulation skills. In addition, health-related quality of life, and snack intake will be analyzed.

Discussion

The computer-based training programs might be a feasible and attractive tool to increase the sustainability of the weight loss reached during inpatient rehabilitation.

Trial registration

The present study protocol was registered on 13 July 2015 at German Clinical Trials Register: DRKS00007879.

The Moderating Role of Body Dissatisfaction in the Relationship between ADHD Symptoms and Disordered Eating in Pediatric Overweight and Obesity

BACKGROUND

Identifying factors linked to disordered eating in overweight and obesity (OV/OB) may provide a better understanding of youth at risk for disordered eating. This project examined whether ADHD symptoms and body dissatisfaction were associated with disordered eating.

METHODS

ADHD symptoms, disordered eating, and body dissatisfaction were assessed in 220 youth ages 7-12 who were OV/OB.

RESULTS

Multiple linear regressions showed that body dissatisfaction and ADHD symptoms were associated with disordered eating.

DISCUSSION

Children with ADHD symptoms and OV/OB may be at greater risk for disordered eating when highly dissatisfied with their bodies. Healthcare providers should assess body image and disordered eating in youth with comorbid OV/OB and ADHD.

Personality and overweight in 6-12-year-old children

BACKGROUND

Personality may be an important yet understudied influence on childhood obesity.

OBJECTIVE

We investigated the association between children's personality traits and weight status in a sample of 1533 6-12 year olds.

METHODS

Mothers rated their child's personality using the Norwegian Hierarchical Personality Inventory for Children, and reported on their child's height and weight.

RESULTS

Relative to their normal weight peers, overweight children were rated lower on energy, optimism, compliance, concentration, perseverance, and self-confidence, and higher on egocentricity, irritability, and anxiety.

CONCLUSIONS

These findings suggest possible mechanisms to investigate in future research relating personality to childhood obesity.

Obesity and dissociable forms of impulsivity in young adults

OBJECTIVE

Obesity is one of the leading causes of preventable morbidity and mortality, and young people are increasingly affected. The aim of this study was to examine relationships between obesity and dissociable forms of impulsivity in young adults.

METHODS

A group of young adults (511) was recruited from city areas in the United States using media advertisements. These young adults were administered careful and extensive clinical and neurocognitive assessment in order to quantify different aspects of impulsivity (behavioral/phenomenological-, cognitive-, and personality-related measures). Associations between obesity and impulsivity were explored using multivariate analysis of variance and discriminant function analysis.

RESULTS

10.8% of the sample was obese, and 21.5% was overweight. Compared to controls, subjects with obesity showed significantly elevated rates of maladaptive gambling behaviors, monetary amounts lost to gambling, nicotine consumption, impulsive action (prolonged stop-signal reaction times in the Stop-Signal Test), and impulsive decision-making (reduced modulation of behavior as a function of risk in the Cambridge Gamble Test). Even accounting for potential confounding variables, obesity was significantly predicted by female gender, older age, more maladaptive gambling behaviors, and worse inhibitory control (stop-signal reaction times).

CONCLUSION

Obesity is associated with several dissociable forms of impulsivity in young people, especially gambling and impulse dyscontrol. Family doctors should screen for gambling problems in obese young adults. Successful treatment of nicotine dependence in young obese people is likely to require intensive weight management support. Neuropsychological deficits relating to impulsivity occur in obese people in early adulthood, and may represent vulnerability markers rather than being due to chronic untoward metabolic effects on brain function.

Visual illusions and inattention: Their association with adiposity among adolescent girls

The Delboeuf concentric circle illusion is frequently invoked as an explanation for the hypothesized association between dinner plate size and overeating. We examined its association with adiposity among 162 girls, aged 14-18 years. We also examined the association of adiposity with neural and behavioral responses during a separate visual discrimination task. The analysis showed that girls with a body mass index percentile ≥ 85, or with greater triceps skinfold thickness, exhibited less sensitivity to the Delboeuf illusion than girls with normal adiposity. The excess adiposity group also exhibited significantly smaller electroencephalographic responses and more errors during the separate visual discrimination task. In combination, the findings from the two tasks suggest that girls with an elevated body mass are less sensitive to visual cues in their environment. The implications of these findings for weight loss education should be considered.

Familial risk for alcohol dependence and developmental changes in BMI: the moderating influence of addiction and obesity genes

AIM

Familial loading for alcohol dependence (AD) and variation in genes reported to be associated with AD or BMI were tested in a longitudinal study.

MATERIALS & METHODS

Growth curve analyses of BMI data collected at approximately yearly intervals and obesity status (BMI > 30) were examined.

RESULTS

High-risk males were found to have higher BMI than low-risk males, beginning at age 15 years (2.0 kg/m(2) difference; p = 0.046), persisting through age 19 years (3.3 kg/m(2) difference; p = 0.005). CHRM2 genotypic variance predicted longitudinal BMI and obesity status. Interactions with risk status and sex were also observed for DRD2 and FTO gene variation.

CONCLUSION

Variation at loci implicated in addiction may be influential in determining susceptibility to increased BMI in childhood and adolescence.

Impact of physical activity on energy balance, food intake and choice in normal weight and obese children in the setting of acute social stress: a randomized controlled trial

BACKGROUND

Psychological stress negatively influences food intake and food choices, thereby contributing to the development of childhood obesity. Physical activity can also moderate eating behavior and influence calorie intake. However, it is unknown if acute physical activity influences food intake and overall energy balance after acute stress exposure in children. We therefore investigated the impact of acute physical activity on overall energy balance (food intake minus energy expenditure), food intake, and choice in the setting of acute social stress in normal weight (NW) and overweight/obese (OW/OB) children as well as the impact of psychological risk factors.

METHOD

After receiving written consent from their parents, 26 NW (BMI < 90(th) percentile) and 24 7-to 11-year-old OW (n = 5)/OB (n = 19, BMI ≥ 90(th) percentile) children were randomly allocated using computer-generated numbers (1:1, after stratification for weight status) to acute moderate physical or to sedentary activity for 30 min. Afterwards, all children were exposed to an acute social stressor. Children and their parents completed self-report questionnaires. At the end of the stressor, children were allowed to eat freely from a range of 12 different foods (6 sweet/6 salty; each of low/high caloric density). Energy balance, food intake/choice and obesity-related psychological risk factors were assessed.

RESULTS

Lower overall energy balance (p = 0.019) and a decreased choice of low density salty foods (p < 0.001) in NW children compared with OW/OB children was found after acute moderate physical activity but not sedentary activity. Independent of their allocation, OW/OB children ate more high density salty foods (104 kcal (34 to 173), p = 0.004) following stress. They scored higher on impulsive behavior (p = 0.005), restrained eating (p < 0.001) and parental corporal punishment (p = 0.03), but these psychological factors were not related to stress-induced food intake/choice. Positive parenting tended to be related to lower intake of sweet high density food (-132 kcal, -277 to 2, p = 0.054).

CONCLUSIONS

In the setting of stress, acute moderate physical activity can address energy balance in children, a benefit which is especially pronounced in the OW/OB. Positive parenting may act as a protective factor preventing stress-induced eating of comfort food.

TRIAL REGISTRATION

clinicaltrials.gov NCT01693926 The study was a pilot study of a project funded by the Swiss National Science Foundation (CRSII3_147673).

Impulsivity and comorbid traits: a multi-step approach for finding putative responsible microRNAs in the amygdala

Malfunction of synaptic plasticity in different brain regions, including the amygdala plays a role in impulse control deficits that are characteristics of several psychiatric disorders, such as ADHD, schizophrenia, depression and addiction. Previously, we discovered a locus for impulsivity (Impu1) containing the neuregulin 3 (Nrg3) gene, of which the level of expression determines levels of inhibitory control. MicroRNAs (miRNAs) are potent regulators of gene expression, and have recently emerged as important factors contributing to the development of psychiatric disorders. However, their role in impulsivity, as well as control of Nrg3 expression or malfunction of the amygdala, is not well established. Here, we used the GeneNetwork database of BXD mice to search for correlated traits with impulsivity using an overrepresentation analysis to filter for biologically meaningful traits. We determined that inhibitory control was significantly correlated with expression of miR-190b, -28a, -340, -219a, and -491 in the amygdala, and that the overrepresented correlated traits showed a specific pattern of coregulation with these miRNAs. A bioinformatics analysis identified that miR-190b, by targeting an Nrg3-related network, could affect synaptic plasticity in the amygdala, targeting bot impulsive and compulsive traits. Moreover, miR-28a, -340, -219a, and possibly -491 could act on synaptic function by determining the balance between neuronal outgrowth and differentiation. We propose that these miRNAs are attractive candidates of regulation of amygdala synaptic plasticity, possibly during development but also in maintaining the impulsive phenotype. These results can help us to better understand mechanisms of synaptic dysregulation in psychiatric disorders.

Effects of weight and gender on a task of inattention

OBJECTIVE

Previous studies have established that obese adolescents possess a stronger tendency to behave more impulsively and be more inattentive than healthy-weight children. Additionally, gender difference in inattention and impulsivity has also been substantiated by previous researchers. The current study examined the relationship between gender, body weight, and inattention and impulsivity in adolescents. It was hypothesized that obese males and females would have more inattentive and impulsive responses than their healthy-weight peers.

METHOD

Participants were 113 adolescents between the ages of 14 and 19; all participants completed the CPT-II, a measure of inattentive and impulsive response styles.

RESULTS

Findings indicated that males who were classified as overweight or obese scored higher on inattention than did obese females, healthy-weight males, and healthy-weight females. Additionally, females committed a greater number of commission errors and were less able to distinguish the target stimuli, suggestive of impulsive responding.

CONCLUSION

These findings indicate a gender difference in regard to impulsive responding, and also reveal an interaction of weight status and gender on inattention. Implications for prevention and treatment are discussed.

Development of family and dietary habits questionnaires: the assessment of family processes, dietary habits and adolescents' impulsiveness in Norwegian adolescents and their parents

Background

There is a need for valid and comprehensive measures of parental influence on children’s energy balance-related behaviours (EBRB). Such measures should be based on a theoretical framework, acknowledging the dynamic and complex nature of interactions occurring within a family. The aim of the Family & Dietary habits (F&D) project was to develop a conceptual framework identifying important and changeable family processes influencing dietary behaviours of 13–15 year olds. A second aim was to develop valid and reliable questionnaires for adolescents and their parents (both mothers and fathers) measuring these processes.

Methods

A stepwise approach was used; (1) preparation of scope and structure, (2) development of the F&D questionnaires, (3) the conducting of pilot studies and (4) the conducting of validation studies (assessing internal reliability, test-retest reliability and confirmatory factor analysis) using data from a cross-sectional study.

Results

The conceptual framework includes psychosocial concepts such as family functioning, cohesion, conflicts, communication, work-family stress, parental practices and parental style. The physical characteristics of the home environment include accessibility and availability of different food items, while family meals are the sociocultural setting included. Individual characteristics measured are dietary intake (vegetables and sugar-sweetened beverages) and adolescents’ impulsivity. The F&D questionnaires developed were tested in a test-retest (54 adolescents and 44 of their parents) and in a cross-sectional survey including 440 adolescents (13–15 year olds), 242 mothers and 155 fathers. The samples appear to be relatively representative for Norwegian adolescents and parents. For adolescents, mothers and fathers, the test-retest reliability of the dietary intake, frequencies of (family) meals, work-family stress and communication variables was satisfactory (ICC: 0.53-0.99). Barratt Impulsiveness Scale-Brief (BIS-Brief) was included, assessing adolescent’s impulsivity. The internal reliability (Cronbach’s alphas: 0.77/0.82) and test-retest reliability values (ICC: 0.74/0.77) of BIS-Brief were good.

Conclusions

The conceptual framework developed may be a useful tool in guiding measurement and assessment of the home food environment and family processes related to adolescents’ dietary habits, in particular and for EBRBs more generally. The results support the use of the F&D questionnaires as psychometrically sound tools to assess family characteristics and adolescent’s impulsivity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-014-0130-z) contains supplementary material, which is available to authorized users.

Preliminary evidence of cognitive and brain abnormalities in uncomplicated adolescent obesity

OBJECTIVE

To ascertain whether pediatric obesity without clinically significant insulin resistance (IR) impacts brain structure and function.

METHODS

Thirty obese and 30 matched lean adolescents, all without clinically significant IR or a diagnosis of metabolic syndrome (MetS), received comprehensive endocrine, neuropsychological, and MRI evaluations.

RESULTS

Relative to lean adolescents, obese non-IR adolescents had significantly lower academic achievement (i.e., arithmetic and spelling) and tended to score lower on working memory, attention, psychomotor efficiency, and mental flexibility. In line with our prior work on adolescent MetS, memory was unaffected in uncomplicated obesity. Reductions in the thickness of the orbitofrontal and anterior cingulate cortices as well as reductions of microstructural integrity in major white matter tracts without gross volume changes were also uncovered.

CONCLUSIONS

It was documented, for the first time, that adolescents with uncomplicated obesity already have subtle brain alterations and lower performance in selective cognitive domains. When interpreting these preliminary data in the context of our prior reports of similar, but more extensive brain findings in obese adolescents with MetS and T2DM, it was concluded that "uncomplicated" obesity may also result in subtle brain alterations, suggesting a possible dose effect with more severe metabolic dysregulation giving rise to greater abnormalities.

Interrelationships among impulsive personality traits, food addiction, and Body Mass Index

OBJECTIVE

Impulsive personality traits have been robustly associated with alcohol and drug misuse, but have received little attention in the context of food addiction. The goal of the current study was to examine the interrelationships between impulsive personality traits, food addiction, and Body Mass Index (BMI), including indirect pathways of influence.

METHOD

Participants (N = 233) completed the Yale Food Addiction Scale (YFAS) to assess patterns of addictive consumption of food, the upps-p impulsivity scale to assess impulsive personality traits, and provided weight and height to generate BMI.

RESULTS

Significant positive associations were found between facets of impulsivity, food addiction symptoms, and BMI. Impulsivity was found to be indirectly associated with BMI by way of associations with addictive consumption of food. In particular, an inclination toward behaving irrationally while experiencing negative mood states (Negative Urgency) and low levels of task persistence (lack of Perseverance) were significantly associated with food addiction directly and that relationship was responsible for their relationship to BMI.

CONCLUSIONS

Dispositional impulsivity, routinely associated with high-risk behaviors including addictive consumption of alcohol and drugs, may be an important risk factor when considering tendency to engage in addictive consumption of food. Monitoring food addiction symptoms early may help reduce the likelihood that compulsive food consumption patterns result in weight gain and obesity. Methodological considerations are discussed.

Rated and measured impulsivity in children is associated with diminished cardiac reactions to acute psychological stress

This study examined the association between impulsivity and heart rate reactions to a brief psychological stress in pre-adolescent children. Impulsivity was assessed by two response inhibition tasks and maternal self-report. Heart rate was measured at rest and in response to a mental arithmetic challenge. Children high in impulsivity showed blunted cardiac stress reactions. This result resonates with previous findings that blunted stress reactivity is characteristic of a range of problematic behaviours often associated with impulsivity.

Reconsidering the link between impulsivity and suicidal behavior

It is widely accepted that suicidal behavior often occurs with little planning. We propose, however, that suicidal behavior is rarely if ever impulsive-that it is too frightening and physically distressing to engage in without forethought-and that suicidal behavior in impulsive individuals is accounted for by painful and fearsome behaviors capable of enhancing their capacity for suicide. We conducted a meta-analysis of the association between trait impulsivity and suicidal behavior and a critical review of research considering the impulsiveness of specific suicide attempts. Meta-analytic results suggest the relationship between trait impulsivity and suicidal behavior is small. Furthermore, studies examining a mediating role of painful and provocative behaviors have uniformly supported our model. Results from our review suggest that researchers have been unable to adequately measure impulsivity of attempts and that measures sensitive to episodic planning must be developed to further our understanding of this phenomenon.

Startling sweet temptations: hedonic chocolate deprivation modulates experience, eating behavior, and eyeblink startle

Many individuals restrict their food intake to prevent weight gain. This restriction has both homeostatic and hedonic effects but their relative contribution is currently unclear. To isolate hedonic effects of food restriction, we exposed regular chocolate eaters to one week of chocolate deprivation but otherwise regular eating. Before and after this hedonic deprivation, participants viewed images of chocolate and images of high-calorie but non-chocolate containing foods, while experiential, behavioral and eyeblink startle responses were measured. Compared to satiety, hedonic deprivation triggered increased chocolate wanting, liking, and chocolate consumption but also feelings of frustration and startle potentiation during the intertrial intervals. Deprivation was further characterized by startle inhibition during both chocolate and food images relative to the intertrial intervals. Individuals who responded with frustration to the manipulation and those who scored high on a questionnaire of impulsivity showed more relative startle inhibition. The results reveal the profound effects of hedonic deprivation on experiential, behavioral and attentional/appetitive response systems and underscore the role of individual differences and state variables for startle modulation. Implications for dieting research and practice as well as for eating and weight disorders are discussed.

Neuropsychological assessment as a predictor of weight loss in obese adolescents

BACKGROUND

Obese individuals are known to be more impulsive than their normal-weight counterparts. Impulsivity has been postulated to be a predictor of weight loss.

DESIGN

A pre-post study was designed to determine for the first time whether impulsivity changed with weight loss during a lifestyle and physical activity intervention programme lasting 2-8 weeks.

SUBJECTS

Fifty-three obese adolescents with a body mass index (BMI) of 33.75 ± 7.9 attending a residential camp were tested and compared at baseline with 50 non-obese adolescents with a mean BMI of 20.6 ± 2.3.

MEASUREMENTS

Inhibitory control was measured with the CANTAB (Cambridge Cognition, Cambridge, UK) Stop Signal Task. MATLAB (The Mathswork Inc., Natick, MA, USA) was used to measure the temporal discounting constant.

RESULTS

The obese group was more impulsive than the normal weight adolescents. BMI reduced significantly from 33.76 kg m(-2) to 30.93 kg m(-2) after completing camp. The stop signal reaction time (SSRT) decreased from 225.38 ± 94.22 to 173.76 ± 107.05 ms (n=47, P=0.0001). A reduction in inhibitory control during camp was predictive of those who showed the greatest reduction in BMI (Wilks' Lambda=0.9, F(1,50)=4.85, P=0.034). The number of weeks in camp (Wilks' Lambda=0.83, F(1,50)=9.826, P=0.003) and the age of the adolescents (Wilks' Lambda=0.87, F(1,50)=5.98, P=0.02) were significantly associated with a reduction in inhibitory control as measured by the SSRT. A longer stay in camp was associated with a greater reduction in SSRT (B=25.45, t=2.02, P=0.05). Increasing age had a significant moderating role in the reduction of inhibitory control (B=-0.3, t=-0.034, P=0.05). Temporal discounting for monetary reward also fell significantly during camp.

CONCLUSION

This study highlights the potential to identify those who are obese by using an easy-to-measure psychometric test. Furthermore, it is the first study to report a reduction in impulsivity and an improvement in well-being as part of a government-approved residential camp for obese adolescents. The potential mechanisms for change in impulsivity with weight are discussed.