Just-in-time response to reward as a function of ADHD symptom severity.

AIM: Attention-deficit hyperactivity disorder (ADHD) neuroimaging studies have identified substantial differences in reward-related circuits on a trial-by-trial basis. However, no research to date has evaluated the effect of motivational context on neural activity in settings with intermittent reward in ADHD. The present study was designed to identify neural processes underlying both immediate effects of reward and sustained effects of reward associated with motivational context in adult ADHD patients. METHODS: We used a functional magnetic resonance imaging paradigm, including a time estimation task with constant versus intermittent reward conditions, in a sample of 21 medication-naïve adults with combined ADHD and 24 healthy adults. RESULTS: Although no between-group neural differences were detected, orbitofrontal activity dropped in association with high ADHD symptom severity during the transition from initial non-reward context blocks to subsequent reward context blocks. In turn, ADHD symptom severity predicted higher orbitofrontal activity in response to immediate reward versus no reward within reward context blocks. CONCLUSION: These results suggest that high ADHD symptom severity scorers adopted a 'just-in-time' strategy, involving the recruitment of reward processing brain areas in the face of immediate reward rather than a sustained response to motivational context.

A school-based program implemented by community providers previously trained for the prevention of eating and weight-related problems in secondary-school adolescents: the MABIC study protocol.

BACKGROUND: The prevention of eating disorders and disordered eating are increasingly recognized as public health priorities. Challenges in this field included moving from efficacy to effectiveness and developing an integrated approach to the prevention of a broad spectrum of eating and weight-related problems. A previous efficacy trial indicated that a universal disordered eating prevention program, based on the social cognitive model, media literacy educational approach and cognitive dissonance theory, reduced risk factors for disordered eating, but it is unclear whether this program has effects under more real-world conditions. The main aim of this effectiveness trial protocol is to test whether this program has effects when incorporating an integrated approach to prevention and when previously-trained community providers implement the intervention. METHODS/DESIGN: The research design involved a multi-center non-randomized controlled trial with baseline, post and 1-year follow-up measures. Six schools from the city of Sabadell (close to Barcelona) participated in the intervention group, and eleven schools from four towns neighboring Sabadell participated in the control group. A total of 174 girls and 180 boys in the intervention group, and 484 girls and 490 boys in the control group were registered in class lists prior to baseline. A total of 18 community providers, secondary-school class tutors, nurses from the Catalan Government's Health and School Program, and health promotion technicians from Sabadell City Council were trained and delivered the program. Shared risk factors of eating and weight-related problems were assessed as main measures. DISCUSSION: It will be vital for progress in disordered eating prevention to conduct effectiveness trials, which test whether interventions are effective when delivered by community providers under ecologically valid conditions, as opposed to tightly controlled research trials. The MABIC project will provide new contributions in this transition from efficacy to effectiveness and new data about progress in the integrated approach to prevention. Pending the results, the effectiveness trial meets the effectiveness standards set down by the Society for Prevention Research. This study will provide new evidence to improve and enhance disordered eating prevention programs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN47682626.

Unhealthy weight-control behaviours, dieting and weight status: a cross-cultural comparison between North American and Spanish adolescents.

The aim of the current study was to examine and compare dieting and unhealthy weight-control behaviours (UWCB) in population-based samples in two large urban areas in Spain (Barcelona) and in the USA (Twin Cities of Minneapolis and St. Paul, Minnesota). Additionally, use of UWCB across weight categories was explored in both samples. Participants included 1501 adolescents from Barcelona (48% girls, 52% boys) and 2793 adolescents from the Twin Cities (53% girls, 47% boys). The main outcome measures were dieting, UWCB (less extreme and extreme) and weight status. Although dieting and UWCB were prevalent in both samples, particularly among girls, the prevalence was higher in the US sample. In both countries, the report of dieting and use of UWCB was highest among overweight and obese youth. Prevention interventions that address the broad spectrum of eating and weight-related problems should be warranted in light of the high prevalence and co-occurrence of overweight and unhealthy weight-related behaviours.

Impact of a school-based disordered eating prevention program in adolescent girls: general and specific effects depending on adherence to the interactive activities.

This study assessed the impact of a school-based program aimed at preventing disordered eating. The program was based on the media-literacy approach and has interactive format. The program was assessed under strong methodological conditions. Seven schools with 263 Spanish adolescent girls in the area of Barcelona, were randomly assigned to either the complete prevention program condition, the partial program condition or the non-treatment control condition, and assessed at pre, post and 6-month follow-up. The program was effective in generating positive changes at follow-up. The effects sizes (ES(d) = 0.29 to ES(d) = 0.38) were greater, on average, than that obtained up to now in selective-universal programs, and similar or greater than that achieved by targeted prevention programs. The results indicate a greater and relevant effect size of the intervention in those participants who completed the inter-session interactive activities (ES(d) = 0.29 to ES(d) = 0.45) although the differences were not significant. These results suggest the importance of monitoring adherence to the activities in all programs defined as "interactive". The implications and limitations of this study are discussed.

Enhanced neural activity in frontal and cerebellar circuits after cognitive training in children with attention-deficit/hyperactivity disorder.

The brain is a plastic entity that can undergo dynamic changes throughout the lifespan as a result of training. Attention-deficit/hyperactivity disorder (ADHD) is commonly treated with psychostimulant medication, and the prevalence of ADHD medication prescription is a topic of heated scientific debate. In addition, cognitive training is frequently provided to patients with ADHD. Although psychostimulant effects have been thoroughly investigated, no previous studies have assessed the neural effects of cognitive training in ADHD. We applied fMRI-paradigms of response inhibition and selective attention to chart the effects of a 10-day cognitive training program in 19 unmedicated ADHD children receiving either cognitive or control training. The two resulting longitudinal datasets were analyzed using whole-brain random-effects general linear models. Although we observed no increases of activity in the control group, both fMRI-datasets revealed enhanced activity after cognitive training in neural structures closely related to ADHD pathophysiology. On the inhibition paradigm, our results indicated increases in orbitofrontal, superior frontal, middle temporal, and inferior frontal cortex. The attentional task was characterized by increased activity in the cerebellum, which correlated with improvement on in-scanner measures of attention. Our findings provide preliminary evidence that cognitive training enhances activity in neural structures typically affected by the disorder. Similar results have been obtained following methylphenidate administration, suggesting that training of cognitive functions may mimic the effects of psychostimulant medication on the brain. These findings postulate a neural account for the potency of cognitive training in ADHD, and hold clinical implications, supporting the inclusion of training programs in standard ADHD-treatment.

Quantitative MR analysis of caudate abnormalities in pediatric ADHD: proposal for a diagnostic test.

Most morphometric magnetic resonance imaging (MRI) studies of pediatric attention-deficit/hyperactivity disorder (ADHD) with appropriate sample sizes reveal a decreased right caudate nucleus volume. Recently, our group reported that this decrease is mainly due to a diminished right caudate body volume (rCBV). Here, we hypothesize that, employing either the total bilateral caudate volume (tbCV) or the bilateral caudate body volume (bCBV) as scaling variables, the rCBV/tbCV and rCBV/bCBV ratios could be found diminished and used as a basis of an imaging diagnostic test. Volumetric caudate nucleus data were obtained from a case-control morphometric MRI study with 39 ADHD subjects and 39 handedness- and IQ-matched controls, using a novel semi-automated caudate segmentation procedure. Student t-tests comparing each relevant ratio were conducted between the two samples. After splitting the samples into two groups, a receiving operator characteristic (ROC) analysis was conducted on the training group to determine the optimal cut-off. Its performance was then examined on the test group. The rCBV/bCBV ratio was found to be statistically different. For a value equal or inferior to 0.48, the specificity was 95.00%. We propose using the rCBV/bCBV ratio to assist in the diagnosis of ADHD in children.

Presence of Distractor Improves Time Estimation Performance in an Adult ADHD Sample.

Objective: It is widely accepted that patients with ADHD exhibit greater susceptibility to distractors, especially during tasks with higher working memory load demands. However, no study to date has specifically measured the impact of distractors on timing functions, although these have consistently shown alterations in ADHD. In this investigation, we aimed to elucidate the neural mechanisms mediating distractor effects on timing functions. Method: We employed a time estimation functional magnetic resonance imaging (fMRI) paradigm including a distracting element in half of the trials in a sample of 21 patients with ADHD and 24 healthy controls. Results: As expected, the effect of the distractor was greater in ADHD patients, where it was associated with increased orbitofrontal activity compared with controls. Behaviorally, time estimation performance benefited from the presence of distractors in both groups. In turn, such improvement correlated with medial frontal and insular activity in the brain. Conclusion: These results suggest that distractors could be stimulating recruitment of frontal resources in ADHD, thus contributing to increase focus on the task.

Differential abnormalities of the head and body of the caudate nucleus in attention deficit-hyperactivity disorder.

The aim of the study is to present a new method for the segmentation of the caudate nucleus and use it to compare the caudate heads and bodies of an attention deficit-hyperactivity disorder (ADHD) group with those of a control group. We used a 1.5-T system to acquire magnetic resonance brain scans from 39 children with ADHD, as defined by DSM-IV TR, and 39 age, handedness and IQ matched controls. The new method for caudate head and body segmentation was applied to obtain semi-automatic volumes and asymmetric patterns. Bilateral volumetric measures of the head, body, and head-body of the caudate nuclei were compared within groups and between ADHD and control groups. Although the group factor was not significant, there were first and second order interactions. The analysis of simple effects showed that the right body and right head+body of the ADHD group was significantly smaller than in the control group, although the ADHD right caudate head was bigger. No ADHD within-group caudate differences were found. Controls showed a significantly larger left caudate head and a significantly bigger caudate right body and right head+body. Our new method for segmenting the caudate nucleus detected differential abnormalities of the right caudate head and body in the ADHD group, explaining previous heterogeneous findings in the literature.

Dieting in Spanish adolescent girls.

This article examines the relation between dieting and non-dieting adolescent girls and body mass index (BMI), eating attitudes and the influence of the aesthetic body shape model. Three hundred forty-nine Spanish adolescent girls in their second year of secondary education were selected. The research design was a cross-sectional ex post facto study and validated measures were used to assess the main variables. Fourteen per cent of the sample was on a diet. Of this group, 69% were overweight, 70% had disordered eating attitudes and 70% were influenced by the current aesthetic body shape model. In all situations, the scores for dieters were significantly higher than those for non-dieters. Although there is not yet any clear consensus with regards to how adolescents interpret the term 'diet', the results indicate major differences between dieters and non-dieters and that those who self-report that they are on a diet present elements of the risk of developing eating and weight disorders.

A controlled assessment of school-based preventive programs for reducing eating disorder risk factors in adolescent Spanish girls.

This study assesses the impact of an eating disorders universal preventive program on a representative sample of Spanish adolescents in the area of Barcelona, Spain. 323 adolescent girls were assigned to three experimental conditions: complete intervention, partial intervention, and non-treatment. The program obtained a significant change in reducing the influences of the aesthetic body ideal and in improving the knowledge of nutrition. Nevertheless, attained post-treatment changes dissipate at the 6 month follow-up. In our opinion, the lack of lasting effects should be attributed to a series of considerations such as format, tests not validated for this age, or insufficient research.

Mediterranean diet adherence among Catalonian adolescents: socio-economic and lifestyle factors.

AIM: This study aims to describe the adherence to the Mediterranean diet (MD), using the KIDMED questionnaire, in a sample of Catalonian adolescents and to assess the association between the MD adherence and socio-economic and lifestyle behaviours. MATERIAL AND METHODS: Data are part of a multi-centre longitudinal study designed for the reduction of risk factors of eating and weight-related problems in adolescents. Here, a cross-sectional analysis was performed with the baseline data, academic period 2010-11. The participants were 1,502 adolescents recruited from 11 schools from the province of Barcelona. RESULTS AND CONCLUSIONS: The results showed a higher level of MD adherence when parents had higher educational level, and when adolescents reported a low level of screen-time, and high weekly physical activity.

The MABIC project: An effectiveness trial for reducing risk factors for eating disorders.

Challenges in the prevention of disordered eating field include moving from efficacy to effectiveness and developing an integrated approach to the prevention of eating and weight-related problems. A previous efficacy trial indicated that a universal disordered eating prevention program, based on the social cognitive model, media literacy educational approach and cognitive dissonance theory, reduced risk factors for disordered eating, but it is unclear whether this program has effects under more real-world conditions. This effectiveness trial tested whether this program has effects when previously trained community providers in an integrated approach to prevention implement the intervention. The research design involved a multi-center non-randomized controlled trial with baseline, post-test and 1-year follow-up measures. The sample included girls in the 8th grade from six schools (n = 152 girls) in a city near Barcelona (intervention group), and from eleven schools (n = 413 girls) in four neighboring towns (control group). The MABIC risk factors of disordered eating were assessed as main outcomes. Girls in the intervention group showed significantly greater reductions in beauty ideal internalization, disordered eating attitudes and weight-related teasing from pretest to 1-year follow-up compared to girls in the control group, suggesting that this program is effective under real-world conditions.

Brain activity and cognition: a connection from thermodynamics and information theory.

The connection between brain and mind is an important scientific and philosophical question that we are still far from completely understanding. A crucial point to our work is noticing that thermodynamics provides a convenient framework to model brain activity, whereas cognition can be modeled in information-theoretical terms. In fact, several models have been proposed so far from both approaches. A second critical remark is the existence of deep theoretical connections between thermodynamics and information theory. In fact, some well-known authors claim that the laws of thermodynamics are nothing but principles in information theory. Unlike in physics or chemistry, a formalization of the relationship between information and energy is currently lacking in neuroscience. In this paper we propose a framework to connect physical brain and cognitive models by means of the theoretical connections between information theory and thermodynamics. Ultimately, this article aims at providing further insight on the formal relationship between cognition and neural activity.

The neuroanatomical basis of panic disorder and social phobia in schizophrenia: a voxel based morphometric study.

OBJECTIVE: It is known that there is a high prevalence of certain anxiety disorders among schizophrenic patients, especially panic disorder and social phobia. However, the neural underpinnings of the comorbidity of such anxiety disorders and schizophrenia remain unclear. Our study aims to determine the neuroanatomical basis of the co-occurrence of schizophrenia with panic disorder and social phobia. METHODS: Voxel-based morphometry was used in order to examine brain structure and to measure between-group differences, comparing magnetic resonance images of 20 anxious patients, 20 schizophrenic patients, 20 schizophrenic patients with comorbid anxiety, and 20 healthy control subjects. RESULTS: Compared to the schizophrenic patients, we observed smaller grey-matter volume (GMV) decreases in the dorsolateral prefrontal cortex and precentral gyrus in the schizophrenic-anxiety group. Additionally, the schizophrenic group showed significantly reduced GMV in the dorsolateral prefrontal cortex, precentral gyrus, orbitofrontal cortex, temporal gyrus and angular/inferior parietal gyrus when compared to the control group. CONCLUSIONS: Our findings suggest that the comorbidity of schizophrenia with panic disorder and social phobia might be characterized by specific neuroanatomical and clinical alterations that may be related to maladaptive emotion regulation related to anxiety. Even thought our findings need to be replicated, our study suggests that the identification of neural abnormalities involved in anxiety, schizophrenia and schizophrenia-anxiety may lead to an improved diagnosis and management of these conditions.

Self-perceived weight status, dieting, and unhealthy weight-control behaviors among Spanish male adolescents.

INTRODUCTION: Self-perceived weight status among adolescents has been associated with weight-control behaviors. However, this relationship varies across weight status. OBJECTIVES: The aim of this study was to examine the effect of self-perceived weight status on dieting and unhealthy weight-control behaviors among Spanish male adolescents, across weight status. METHOD: Participants were 597 Spanish male adolescents (M = 13.94 years old, SD = 0.60). Body weight and height were measured in situ. Self-perceived weight status, dieting, and unhealthy weight-control behaviors were evaluated. RESULTS: The adolescents were inaccurate on estimating their weight status. Those who were overweight or obese, or who perceived themselves to be so, were more likely to report dieting and unhealthy weight-control behaviors. DISCUSSION: There is a need to promote healthier eating behaviors among adolescents, and to take into account the fact that self-perceived weight status may hinder the adoption of such behaviors.

Introducción: El estatus de peso percibido se ha asociado a conductas de control del peso en adolescentes. Esta relación varía de acuerdo al estatus de peso corporal. Objetivos: Explorar el efecto del estatus de peso percibido sobre la práctica de dieta y conductas no saludables de control del peso en adolescentes varones españoles, considerando su estatus de peso. Método: Participaron 597 adolescentes (M = 13,94 años, DS = 0,60). Se registró in situ la talla y peso corporal. Se evaluó el peso percibido, la práctica de dieta y conductas no saludables de control del peso. Resultados: Los adolescentes fueron inexactos al estimar su estatus de peso. Aquellos con sobrepeso, obesidad o los que se percibían como tales, fueron los que más informaron hacer dieta y conductas no saludables de control del peso. Discusión: Es necesario promover conductas alimentarias saludables entre los adolescentes y considerar que el estatus de peso percibido puede limitar la adopción de estos comportamientos.

Sociocultural influences and body change strategies in Spanish adolescent boys of different weight status.

The aim of the present study was to examine the association between sociocultural influences to attain an ideal body and body change strategies (BCS) in Spanish adolescent boys of different weight status. A total of 594 Spanish boys (M=13.94 years, SD=0.20) participated. Measures included in the study were weight status according to body mass index (BMI), sociocultural influences (perceived pressures to attain an ideal body, general internalization of an ideal body, internalization of an athletic-ideal body), BCS to lose/control weight (dieting, healthy and unhealthy weight-control behaviors), and BCS to gain weight and muscles. Underweight boys engaged more frequently in weight-gain behaviors. Overweight boys reported higher levels of perceived sociocultural pressures and general internalization compared to normal-weight boys, and were more likely to be engaged in BCS to lose/control weight compared with the other weight-status groups. There were no differences between groups in terms of internalization of an athletic-ideal body and BCS to increase muscles. Future research and prevention programs should consider male-specific behaviors and weight-status differences.

Analysis of the factor structure of the Sociocultural Attitudes Towards Appearance Questionnaire (SATAQ-3) in Spanish secondary-school students through exploratory structural equation modeling.

The aims of the present study were: (1) to assess the factor structure of the SATAQ-3 in Spanish secondary-school students by means of exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and exploratory structural equation modeling (ESEM) models; and (2) to study its invariance by sex and school grade. ESEM is a technique that has been proposed for the analysis of internal structure that overcomes some of the limitations of EFA and CFA. Participants were 1559 boys and girls in grades seventh to tenth. The results support the four-factor solution of the original version, and reveal that the best fit was obtained with ESEM, excluding Item 20 and with correlated uniqueness between reverse-keyed items. Our version shows invariance by sex and grade. The differences between scores of different groups are in the expected direction, and support the validity of the questionnaire. We recommend a version excluding Item 20 and without reverse-keyed items.

Cerebellar neurometabolite abnormalities in pediatric attention/deficit hyperactivity disorder: a proton MR spectroscopic study.

We designed a case-control proton magnetic resonance spectroscopic study comparing the cerebellar and prefrontal regions of a group of 17 ADHD (attention deficit/hyperactivity disorder) medicated children and a group of 17 control children matched for laterality, gender and age. As we had found decreased gray matter volume in the right prefrontal region and the left cerebellar hemisphere in a previous voxel-based morphometry study conducted on an independent ADHD sample, we tested the hypothesis that these regions should show neurometabolite abnormalities. MRI (magnetic resonance imaging) was performed with a 1.5 T system; spectral acquisition was performed with a single-voxel technique and a PRESS sequence. Two volumes of interest were selected in the right prefrontal region and the left cerebellar hemisphere. NAA (N-acetylaspartate), Cre (creatine), Cho (choline), MI (myo-inositol) and Glx (glutamate-glutamine) resonance intensities were absolutely quantified. In the left cerebellar hemisphere, ADHD children showed significant decreased MI and NAA absolute concentrations with high effect sizes (p=0.004, ES=1.184; p=0.001, ES=1.083). The diminished absolute concentration of the NAA could be related to a gray matter volume decrease in the same cerebellar region found in the previous voxel-based morphometry MRI study, while the reduced MI absolute concentration could express a decreased glial density. This is the first proton MR spectroscopic study examining the cerebellum and it provides additional support for the role of cerebellum in the ADHD neurobiology.

Neurobiological substrates of social cognition impairment in attention-deficit hyperactivity disorder: gathering insights from seven structural and functional magnetic resonance imaging studies.

Social cognitive neuroscience is beginning to unravel a neuroanatomy of social cognition, networks of brain regions especially involved in social cognition and social functioning. It is widely acknowledged that social functioning and social cognition are impaired in attention-deficit hyperactivity disorder (ADHD). Although an impressive amount of neuroscientific research has been conducted in ADHD, little effort has been made to link those deficits in social cognition and functioning to the well-known brain abnormalities detected in structural and functional neuroimaging studies. We review seven functional and magnetic resonance studies conducted at our laboratory in ADHD samples during the last 5 years in order to scrutinize whether the putative neuroanatomic regions underpinning social cognition are affected in ADHD. The orbitofrontal cortex (OFC), the caudate nucleus, the ventral striatum, and the cerebellum are among those regions that displayed functional or morphometric abnormalities in our ADHD samples. The OFC is clearly involved in social cognition, and several features of OFC dysfunction may be related to the social cognition and function impairment in ADHD. In contrast to the OFC, the role of the caudate nucleus, the ventral striatum, and the cerebellum is elusive. However, on one hand, there is converging evidence from human and animal neuropsychology, neuroscience, and psychiatry that support the role of such areas in social cognition, mainly through its involvement in emotional processing. On the other hand, the morphometric and functional ADHD abnormalities in these regions could account for the impoverished social functioning and the deficient social cognition skills of ADHD children.