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For 50 years, attention-deficit/hyperactivity disorder (ADHD) has been considered a disorder of executive control (EC), the higher-order, cognitive skills that support self-regulation, goal attainment and what we generally call "attention." This review surveys our current understanding of the nature of EC as it pertains to ADHD and considers the evidence in support of eight hypotheses that can be derived from the EC theory of ADHD. This paper provides a resource for practitioners to aid in clinical decision-making. To support theory building, I draw a parallel between the EC theory of ADHD and the common gene–common variant model of complex traits such as ADHD. The conclusion offers strategies for advancing collaborative research. • Evidence for eight hypotheses for the role of executive control (EC) in attention-deficit/hyperactivity disorder (ADHD) is considered. • The review concludes that there is growing evidence in support of the key hypotheses derived from the EC theory of ADHD. • Suggestions are made for future research based, in part, on the similarities between research in genetics of ADHD and that of EC. [ABSTRACT FROM AUTHOR]

Objective: To assess the phenomenology and predictive factors of attention-deficit/hyperactivity disorder (ADHD) after traumatic brain injury (TBI), also called secondary ADHD (SADHD). Method: Children without preinjury ADHD 5-14 years old with TBI from consecutive admissions (n = 143) to five trauma centers were observed prospectively from 6 to 12 months (12-month assessment) and from 12 to 24 months (24-month assessment) postinjury with semistructured psychiatric interviews. Injury and preinjury psychosocial variables were assessed. Results: SADHD occurred in 15 of 103 (15%) of participants between 6 and 12 months after injury and 17 of 82 (21%) in the second year after injury. SADHD was significantly (p < .05) comorbid with personality change due to TBI and new-onset disruptive behavior disorders. Preinjury adaptive function was a consistent predictor of SADHD. Regression analyses revealed that preinjury psychosocial adversity was an independent predictor of SADHD in the second year after injury. Neither severity of injury nor lesion location predicted SADHD from 6 to 24 months postinjury. Conclusions: Determination of preinjury psychosocial adversity and the child's preinjury functioning during the index hospitalization would improve identification of children at highest risk of development of SADHD. [ABSTRACT FROM AUTHOR]

Objective: To assess the phenomenology and predictive factors of attention-deficit/hyperactivity disorder (ADHD) after traumatic brain injury (TBI), also called secondary ADHD (SADHD). Method: Children without preinjury ADHD 5-14 years old with TBI from consecutive admissions (n = 143) to five trauma centers were observed prospectively for 6 months (base-line and 6 months), with semistructured psychiatric interviews. Injury severity, lesion characteristics, and preinjury variables including psychiatric disorder, family psychiatric history, family psychiatric history of ADHD, family function, socioeconomic status, psychosocial adversity, and adaptive function were assessed with standardized instruments. Results: SADHD in the first 6 months after injury occurred in 18 of 115 (16%) of returning participants. All subtypes of ADHD occurred. Socioeconomic status (p = .041) and orbitofrontal gyrus lesions (p = .005) independently significantly predicted SADHD. Conclusions: These findings are consistent with research on developmental ADHD that implicate psychosocial factors and prefrontal structural and functional differences between those with and without the disorder. [ABSTRACT FROM AUTHOR]

Presents a study which enhanced the diagnostic accuracy of attention-deficit/hyperactivity disorder. Methodology and results; Limitations of the study; Clinical implications.

Presents Attention-deficit hyperactivity disorder (ADHD) as the most common psychiatric disorders of childhood. Use of Methylphenidate (MPH) as treatment of choice for ADHD in North America; Reports on various occurence of Tics on children with ADHD treated with MPH; Information on the procedure in giving MPH as medication and results it has yielded.

Investigates whether the presence of comorbid oppositional defiant disorder (ODD) or conduct disorder (CD) alters the correlates of attention-deficit hyperactivity disorder (ADHD). Details on the methods used; Indication of the findings; Information on the conclusion reached.

Presents information from a study which examines the effects of methylphenidate (MPH) treatment on attention-deficit hyperactivity disorder (ADHD), along with nonpharmacological treatment. Information on methods of treatment for children with ADHD and its effects; Advantages of MPH; Development of a Telephone Interview Probe (TIP) to assess behavior.

An abstract of the article "From Community to Clinic and Back: What Population-Based Samples Can Tell Us About the Genetics of Psychopathology in Youth" by Russell J. Schachar and Erik G. Willcutt is presented.

An abstract of the article "Impact on the Family Unit of Early-Morning Functioning Impairments in Stimulant-Treated Children and Adolescents With Attention-Deficit/Hyperactivity Disorder" by Russell J. Schachar and colleagues is presented.

The article presents a case study which researches how aftercare for children in the U.S. and Canada impacts emergency department (ED) visits and psychiatric hospitalization readmission by examining health administrative databases. Children in need of mental health services were assessed, and the results found that aftercare increases the possibility of readmission and continuity of care, but it did not increase the need for ED visits or emergency psychiatry.

Abstract: The goal of the present study was to investigate parent-of-origin effects in attention-deficit hyperactivity disorder (ADHD). Parent-of-origin effects in ADHD may be due to differences in the relative quantity of risk factors transmitted by each parent. Alternatively, parent-of-origin effects may be produced by qualitative differences in the risks transmitted, such as those carried on the sex chromosomes or regulated by genomic imprinting. 60 children with maternal-only history of ADHD and 131 children with paternal-only history of ADHD were compared on three domains for which prior evidence suggested parent-of-origin effects may exist: core symptoms, disruptive behaviours and depression. Dependent variables were derived from previously validated, age-appropriate and standardized parent and teacher interviews and questionnaires. Depression levels were rated using the Child Depression Inventory. Consistent with previous research and the predictions derived from threshold models of ADHD etiology, the maternal history group received higher ratings of behavioural disorder (ADHD, conduct disorder and oppositional symptoms) than the paternal history group. Parent-of-origin effects were also observed for depression, with the paternal history group rating themselves as significantly more depressed than children in the maternal history group, particularly girls. Heightened paternal transmission relative to maternal is suggestive of genomic imprinting, and the interaction with proband sex indicates the involvement of the sex chromosomes or sex-specific physiological or hormonal factors. Interpretations of these data in terms of environmental and genetic factors, including epigenetic and sex-linked hypotheses, are explored. [Copyright &y& Elsevier]

Abstract Background Attention-deficit/hyperactivity disorder (ADHD) is a major sequela of traumatic brain injury (TBI) in youths. The objective of this study was to examine whether ADHD symptoms are differentially associated with genetic risk and brain structure in youths with and without a history of TBI. Methods Medical history, ADHD symptoms, genetic data, and neuroimaging data were obtained from a community sample of youths. ADHD symptom severity was compared between those with and without TBI (TBI n = 418, no TBI n = 3193). The relationship of TBI history, genetic vulnerability, brain structure, and ADHD symptoms was examined by assessing 1) ADHD polygenic score (discovery sample ADHD n = 19,099, control sample n = 34,194), 2) basal ganglia volumes, and 3) fractional anisotropy in the corpus callosum and corona radiata. Results Youths with TBI reported greater ADHD symptom severity compared with those without TBI. Polygenic score was positively associated with ADHD symptoms in youths without TBI but not in youths with TBI. The negative association between the caudate volume and ADHD symptoms was not moderated by a history of TBI. However, the relationship between ADHD symptoms and structure of the genu of the corpus callosum was negative in youths with TBI and positive in youths without TBI. Conclusions The identification of distinct ADHD etiology in youths with TBI provides neurobiological insight into the clinical heterogeneity in the disorder. Results indicate that genetic predisposition to ADHD does not increase the risk for ADHD symptoms associated with TBI. ADHD symptoms associated with TBI may be a result of a mechanical insult rather than neurodevelopmental factors. [ABSTRACT FROM AUTHOR]

This study examined whether depression, irritability, and anxiety symptoms, which often accompany ADHD, mediate between ADHD and suicidality. Calculated separately for the parent report and the teacher report (values detailed, respectively), ADHD symptoms were associated with depression (B = 0.21; B = 0.15, p < 0.001 for both), anxiety (B = 0.13; B = 0.07, p < 0.001 for both), and irritability (B = 0.16; B = 0.16, p < 0.001 for both) symptoms. Both parent report- and teacher report-based models indicated that depression (60 and 55% of total association, respectively) and irritability (35 and 48% of total association, respectively), but not anxiety symptoms, mediated the association between ADHD and suicidality. [Extracted from the article]

Objective:Several neurodevelopmental disorders are associated with social processing deficits. The objective of this study was to compare patterns of social perception abilities across obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and control participants. Method: A total of 265 children completed the Reading the Mind in the Eyes Test-Child Version (RMET). Parents or caregivers completed established trait/symptom scales. The predicted percentage of accuracy on the RMET was compared across disorders and by item difficulty and item valence (i.e., positive/negative/neutral mental states), then analyzed for associations with trait/symptom scores. Results: The percentage of correct RMET scores varied significantly between diagnostic groups (p < .0001). On pairwise group comparisons controlling for age and sex, children with ADHD and ASD scored lower than the other groups (p < .0001). When IQ was also controlled for in the model, participants with OCD performed better than controls (p < .001), although differences between other groups were less pronounced. Participants with ASD scored lowest on easy items. Those with ASD and ADHD scored significantly lower than other groups on items with positive valence (p < .01). Greater social communication impairment and hyperactivity/impulsivity, but not OCD traits/symptoms, were associated with lower scores on the RMET, irrespective of diagnosis. Conclusion: Social perception abilities in neurodevelopmental disorders exist along a continuum. Children with ASD have the greatest deficits, whereas children with OCD may be hypersensitive to social information. Social communication deficits and hyperactive/impulsive traits are associated with impaired social perception abilities; these findings highlight overlapping cognitive and behavioral manifestations across disorders. [ABSTRACT FROM AUTHOR]

Obsessive–compulsive disorder (OCD) has a typical onset during childhood or adolescence. Although recent in-vivo proton magnetic resonance spectroscopy (1H-MRS) studies report gray matter metabolite abnormalities in children and adolescents with OCD, there are no existing 1H-MRS studies that measure white matter (WM) metabolite levels in this population. In the present study, we measured metabolite levels in the left and right prefrontal WM (LPFWM and RPFWM, respectively) of psychotropic-naïve children and adolescents with OCD (LPFWM: N=15, mean age 13.3±2.4 years; right RPFWM: N=14, mean age 13.0±2.3 years) and healthy controls (LPFWM: N=17, mean age 11.8±2.7 years; RPFWM: N=18, mean age 12.2±2.8 years). Spectra were acquired using a 3T single voxel PRESS sequence (1.5×2.0×2.0cm3). When age and sex effects were controlled, OCD patients had higher levels of RPFWM choline and N-acetyl-aspartate (NAA). In addition, RPFWM levels of NAA, creatine and myo-inositol were positively and significantly correlated with severity of OCD symptoms. In summary, this is the first published study of WM metabolite levels in children and adolescents with OCD. Our preliminary findings lend further support to the previous findings of WM abnormalities in OCD. [ABSTRACT FROM AUTHOR]

Background: Fronto-amygdalar networks are implicated in childhood psychiatric disorders characterized by high rates of externalizing (aggressive, noncompliant, oppositional) behavior. Although externalizing behaviors are distributed continuously across clinical and nonclinical samples, little is known about how brain variations may confer risk for problematic behavior. Here, we studied cortical thickness, amygdala volume, and cortico-amygdalar network correlates of externalizing behavior in a large sample of healthy children. Methods: Two hundred ninety-seven healthy children (6–18 years; mean = 12 ± 3 years), with 517 magnetic resonance imaging scans, from the National Institutes of Health Magnetic Resonance Imaging Study of Normal Brain Development, were studied. Relationships between externalizing behaviors (measured with the Child Behavior Checklist) and cortical thickness, amygdala volume, and cortico-amygdalar structural networks were examined using first-order linear mixed-effects models, after controlling for age, sex, scanner, and total brain volume. Results significant at p ≤ .05, following multiple comparison correction, are reported. Results: Left orbitofrontal, right retrosplenial cingulate, and medial temporal cortex thickness were negatively correlated with externalizing behaviors. Although amygdala volume alone was not correlated with externalizing behaviors, an orbitofrontal cortex-amygdala network predicted rates of externalizing behavior. Children with lower levels of externalizing behaviors exhibited positive correlations between orbitofrontal cortex and amygdala structure, while these regions were not correlated in children with higher levels of externalizing behavior. Conclusions: Our findings identify key cortical nodes in frontal, cingulate, and temporal cortex associated with externalizing behaviors in children; and indicate that orbitofrontal-amygdala network properties may influence externalizing behaviors, along a continuum and across healthy and clinical samples. [ABSTRACT FROM AUTHOR]

Background: Reading disabilities (RD) and attention-deficit hyperactivity/disorder (ADHD) are two common childhood disorders that co-occur by chance more often than expected. Twin studies and overlapping genetic linkage findings indicate that shared genetic factors partially contribute to this comorbidity. Linkage of ADHD to 6p, an identified RD candidate locus, has previously been reported, suggesting the possibility of a pleiotropic gene at this locus. RD has been previously associated with five genes in the region, particularly DCDC2 and KIAA0319. Methods: To test whether these genes also contribute to ADHD, we investigated markers previously associated with RD for association with ADHD and ADHD symptoms in a sample of families with ADHD (n = 264). Markers were located in two subregions, VMP/DCDC2 and KIAA0319/TTRAP. Results: Across all analyses conducted, strong evidence for association was observed in the VMP/DCDC2 region. Association was equally strong with symptoms of both inattention and hyperactivity/impulsivity, suggesting that this locus contributes to both symptom dimensions. Markers were also tested for association with measures of reading skills (word identification, decoding); however, there was virtually no overlap in the markers associated with ADHD and those associated with reading skills in this sample. Conclusions: Overall this study supports a previous linkage study of ADHD indicating a risk gene for ADHD on 6p and points to VMP or DCDC2 as the most likely candidates. [Copyright &y& Elsevier]

Abstract: ADHD is a heritable condition of childhood for which several risk alleles have been identified. However, observed effect sizes have been small and few replicated polymorphisms have been identified. There are many reasons for the lack of one-to-one correspondence between genotype and phenotype in ADHD. Endophenotypes are non-clinical markers of genetic risk which may facilitate gene discovery in complex disorders like ADHD. The most common endophenotypes under consideration in ADHD are neuropsychological measures of executive function, although a range of psychological, physiological and neuroanatomical endophenotypes have been proposed. If carefully chosen, endophenotypes have the potential to increase the power of genetic research to identify susceptibility genes. If not carefully selected, endophenotypes may generate false negative and false positive results. This paper reviews the theoretical rationale for endophenotypes and proposes a priori criteria by which ADHD endophenotypes should be selected and validated. The literature on motor response inhibition is reviewed to illustrate the validation process which is recommended in the selection of other candidate endophenotypes. [Copyright &y& Elsevier]

Abstract: The dopamine system plays an important role in the regulation of attention and motor behavior, subsequently, several dopamine-related genes have been associated with Attention Deficit/Hyperactivity Disorder (ADHD). Among them are the dopamine receptors D1 and D5 that mediate adenylyl cyclase activation through coupling with Gs-like proteins. We thus hypothesized that the Gs-like subunit Gαolf, expressed in D1-rich areas of the brain, contributes to the genetic susceptibility of ADHD. To evaluate the involvement of the Gαolf gene, GNAL, in ADHD, we examined the inheritance pattern of 12 GNAL polymorphisms in 258 nuclear families ascertained through a proband with ADHD (311 affected children) using the transmission/disequilibrium test (TDT). Categorical analysis of individual marker alleles demonstrated biased transmission of one polymorphism in GNAL intron 3 (rs2161961; P =0.011). We also observed significant relationships between rs2161961 and dimensional symptoms of inattention and hyperactivity/impulsivity (P =0.003 and P =0.008). In addition, because of recent evidence of imprinting at the GNAL locus, secondary analyses were split into maternal and paternal transmissions to assess a contribution of parental effects. We found evidence of strong maternal effect, with preferential transmission of maternal alleles for rs2161961A (P =0.005) and rs8098539A (P =0.035). These preliminary findings suggest a possible contribution of GNAL in the susceptibility to ADHD, with possible involvement of parent-of-origin effects. [Copyright &y& Elsevier]

Objective: Long-term effects of psychostimulants on growth in height and in weight are investigated in children with attention-deficit/hyperactivity disorder. Method: Participants were 79 children, 6 to 12 years of age, with attention-deficit/hyperactivity disorder, who were followed annually for up to 5 years, between the years 1993 and 1994 and 1998 and 1999. Annual height and weight measurements were standardized by age and gender using the 2000 Centers for Disease Control and Prevention Growth Charts for the United States and reported as z scores. For children taking stimulants throughout the previous school year, dose potency was standardized to methylphenidate in milligrams per kilogram per day. We used hierarchical linear modeling to investigate the influence of dose and duration of stimulant treatment on the rate of growth in height and weight. Results: Controlling for time since initiation of treatment, daily dose of stimulant medication was negatively associated with z scores for height (13 = -.11, SE = 0.03, p < .01 ) and for weight (β = -.29, SE = 0.04, p < .01). Estimates based on the statistical model suggest that children receiving ≥1.5 mg/kg/day methylphenidate will show diminished weight gain after 1 year; those receiving ≥2.5 mg/kg/day methylphenidate will show diminished gains in height after 4 years. Conclusion: Long-term use of high doses of stimulants during a period of 1 to 5 years is likely to have measurable effects on the rate of growth in school-age children with attention-deficit/hyperactivity disorder. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To measure possible positional and diurnal physiological effects on brain metabolites in single-voxel proton magnetic resonance spectroscopy (1H-MRS) measurements of the right and left striatum. Methods: 1H-MRS measurements were performed in 10 healthy adult volunteers using a short echo PRESS sequence (TE=30 ms, TR=3000 ms). Each individual was scanned during both morning and afternoon hours. Regions of interest were right and left striatum. To control for systematic drift in scanner performance, 1H-MRS measurements of a standard phantom solution were also acquired. Statistical analysis was performed using a repeated measures analysis of variance that included three within-subject factors: metabolite (N-acetyl-aspartate [NAA] or creatine [Cr]), laterality (left or right caudate) and time (morning or afternoon). Results: A significant interaction (P<.016) between time of day and metabolite levels was observed. Further exploration of this finding revealed a significant difference between morning and afternoon levels of NAA (P<.044) but not Cr. In addition, no significant morning-to-afternoon differences were observed for the 1H-MRS phantom measurements. Conclusions: Systematic variation due to scanner performance does not account for the changes observed in repeated measurements of striatal NAA levels. This difference may be accounted for by either repositioning effects or circadian physiological effects. Further studies are required to learn whether time of day standardization of 1H-MRS acquisitions may contribute to improved reproducibility of measurements. [Copyright &y& Elsevier]

Objective: To assess the phenomenology and predictive factors of personality change due to traumatic brain injury. Method: Children (N = 177), aged 5 to 14 years with traumatic brain injury from consecutive admissions to five trauma centers, were followed prospectively at baseline and 6 months with semistructured psychiatric interviews. Injury severity, lesion characteristics, and preinjury variables including psychiatric disorder, family psychiatric history, family function, socioeconomic status, psychosocial adversity, and adaptive function were assessed with standardized instruments. Results: Personality change occurred in 22% of participants in the first 6 months after injury. Severity of injury predicted personality change, whereas none of the psychosocial variables predicted personality change. Lesions of the dorsal prefrontal cortex, specifically the superior frontal gyrus, were associated with personality change after controlling for severity of injury or the presence of other lesions. Conclusions: These findings are consistent with models of affective dysregulation that implicate a dorsal prefrontal cortex system important for effortful regulation of affective states. [ABSTRACT FROM AUTHOR]

Objective: To identify approaches to improving methods for assessing tolerability and safety of psychotropic medications in children and adolescents. Method: Strengths and limitations of current methodology were reviewed and possible alternatives examined. Results: Research on the validity of safety evaluation has been extremely limited. No evidence-based "gold standard" exists. Clinical trials remain the best design to establish causality, but sample size limitations prevent the detection of infrequent, though serious, adverse events. Other designs, such as cohort and casecontrol studies, and approaches, such as mining of large databases, must be considered. Conclusions: The current lack of methodological standardization across studies prevents generalizations and meta-analyses. Because the issues relevant to drug safety are diverse, a variety of methodological approaches and instruments are needed. It is, however, possible to adopt standard basic definitions of adverse events, degree of severity, ascertainment methods, and recording procedures, as a common "core," to which more specific assessment instruments can be added. Systematic empirical testing and validation of safety methodology is needed. [ABSTRACT FROM AUTHOR]

Background: In recent years, a number of studies have begun to explore the nature of Attention-Deficit/Hyperactivity Disorder (ADHD) in children with Autism Spectrum Disorder (ASD). In this study, we examined the relationship between both symptoms of ADHD and symptoms of ASD on cognitive task performance in a sample of higher-functioning children and adolescents with ASD. Participants completed cognitive tasks tapping aspects of attention, impulsivity/inhibition, and immediate memory.Aims: We hypothesized that children with ASD who had higher levels of ADHD symptom severity would be at higher risk for poorer sustained attention and selective attention, greater impulsivity/disinhibition, and weaker memory.Methods and Procedures: The sample included 92 children (73 males) diagnosed with ASD (Mean Age = 9.41 years; Mean Full Scale IQ = 84.2).Outcomes and Results: Using regression analyses, more severe ADHD symptomatology was found to be significantly related to weaker performance on tasks measuring attention, immediate memory, and response inhibition. In contrast, increasing severity of ASD symptomatology was not associated with higher risk of poorer performance on any of the cognitive tasks assessed.Conclusions and Implications: These results suggest that children with ASD who have more severe ADHD symptoms are at higher risk for impairments in tasks assessing attention, immediate memory, and response inhibition-similar to ADHD-related impairments seen in the general pediatric population. As such, clinicians should assess various aspects of cognition in pediatric patients with ASD in order to facilitate optimal interventional and educational planning. [ABSTRACT FROM AUTHOR]