Neuroanatomical abnormalities in adolescents with attention-deficit/hyperactivity disorder

ObjectiveSeveral neuroanatomic abnormalities have been reported in patients with attention-deficit/hyperactivity disorder (ADHD). However, findings are not always consistent, perhaps because of heterogeneous subject samples. Studying youths with documented familial ADHD provides an opportunity to examine a more homogeneous population.MethodTwenty-four youths with a confirmed history of familial ADHD and 10 control youths underwent high-resolution structural magnetic resonance imaging examinations. Archived magnetic resonance imaging scan data from 12 control youths were included in the analysis to increase statistical power. Individually drawn region-of-interest methods were used to examine the frontal lobe gyri and caudate.ResultsCerebral total tissue was similar between groups. The volumes of the right caudate and right inferior frontal lobe were larger in the ADHD youths compared with the control youths. Data from a subgroup of the ADHD youths suggest that increasing left caudate volume is associated with decreasing functional activation of this region.ConclusionsBecause previous studies have focused primarily on younger subjects or used an extended age range, the present results may reflect neurodevelopmental changes specific to late adolescence in familial ADHD.     

White matter abnormalities and their impact on attentional performance in adult attention-deficit/hyperactivity disorder

Inattention is the most important behavioral feature of adult patients with attention-deficit/hyperactivity disorder (ADHD). Neuroimaging studies in ADHD have demonstrated abnormalities primarily in the frontostriatal circuitry and were mostly conducted in children. We investigated white matter (WM) integrity in adult ADHD patients and the correlation of WM microstructure and neuropsychological parameters in 37 (21 men) never-medicated adult ADHD patients and 34 age- and gender-matched healthy controls. All subjects underwent clinical interviews, rating scales, and neuropsychological tests of attentional performance. Diffusion tensor imaging (DTI) was acquired, and 12 WM regions-of-interest (ROIs) within the attentional network were chosen. Group differences of mean fractional anisotropy (FA) and mean diffusivity (MD) values were calculated for each ROI, and patients' DTI measures were then correlated with measures of attentional performance. FA values in ADHD patients were significantly reduced in the left inferior longitudinal fasciculus (ILF), while MD values were significantly increased in ADHD patients in the frontal portion of the left frontooccipital fasciculus (IFO). In ADHD patients, MD values were negatively correlated with attentional performance in the left ILF. Our findings provide further support for disturbed frontostriatal structural connectivity and also point to an involvement of the left temporal white matter with an impact on attentional performance.     

The influence of risperidone on attentional functions in children and adolescents with attention-deficit/hyperactivity disorder and co-morbid disruptive behavior disorder

This study aims to examine the influence of risperidone on various attentional functions, including intensity and selectivity aspects of attention plus inhibitory control in children with attention deficit/hyperactivity disorder (ADHD) with co-morbid Disruptive Behavior Disorders (DBD) and normal IQ. Children with ADHD and DBD, aged 8-15 years, were treated with risperidone (mean daily dose: 1.5 mg; n = 23) and examined with three attentional paradigms before and after a 4-week treatment period. Age- and IQ-matched normal controls (n = 23) were also tested without medication on the same two occasions. No influence of the medication could be detected for any neuropsychological variable, neither as a positive enhancement nor as adverse side effects. However, clinical symptoms of ADHD and DBD assessed on the IOWA Conners Scale significantly improved after the 4-week treatment period. Divergent behavioral and cognitive effects of risperidone on ADHD symptoms were observed, with a significant reduction in behavioral symptoms, whereas no positive treatment effects were found on laboratory tasks of impulsivity. Thus, the cognitive effects of risperidone seem to differ from the cognitive effects of stimulant treatments in children with ADHD + DBD. However, no negative impact of risperidone was observed on attentional functions either, i.e., there was no slowing of cognitive speed.     

Cytogenetic abnormalities in attention-deficit/hyperactivity disorder

OBJECTIVE: To systematically assess the prevalence of fragile X syndrome, velocardiofacial syndrome, and other cytogenetic abnormalities in a group of children with attention-defict/hyperactivity disorder (ADHD). METHOD: Blood samples were obtained from 100 children (64 boys) with combined type ADHD and normal intelligence and analyzed for the presence of fragile X mutation expansions, the 22q11.2 microdeletion associated with velocardiofacial syndrome, and cytogenetic abnormalities that would be detected with high resolution chromosomal banding. RESULTS: One girl with ADHD had a sex chromosome aneuploidy (47,XXX). One boy had a premutation-sized allele for fragile X; no subjects showed the full mutation. Testing for 22q11.2 microdeletion was negative for all subjects with ADHD screened. None of these differences exceeded those expected by chance. CONCLUSIONS: In the absence of clinical signs or positive family history, these relatively expensive laboratory assessments are not clinically indicated for children with ADHD and normal intelligence, and are not recommended as a component of other genetic investigations of this disorder.     

Microstructural abnormalities of the brain white matter in attention-deficit/hyperactivity disorder

Background

Attention-deficit/hyperactivity disorder (ADHD) is an early-onset neurodevelopmental disorder with multiple behavioural problems and executive dysfunctions for which neuroimaging studies have reported a variety of abnormalities, with inconsistencies partly owing to confounding by medication and concurrent psychiatric disease. We aimed to investigate the microstructural abnormalities of white matter in unmedicated children and adolescents with pure ADHD and to explore the association between these abnormalities and behavioural symptoms and executive functions.

Methods

We assessed children and adolescents with ADHD and healthy controls using psychiatric interviews. Behavioural problems were rated using the revised Conners’ Parent Rating Scale, and executive functions were measured using the Stroop Colour-Word Test and the Wisconsin Card Sorting test. We acquired diffusion tensor imaging data using a 3 T MRI system, and we compared diffusion parameters, including fractional anisotropy (FA) and mean, axial and radial diffusivities, between the 2 groups.

Results

Thirty-three children and adolescents with ADHD and 35 healthy controls were included in our study. In patients compared with controls, FA was increased in the left posterior cingulum bundle as a result of both increased axial diffusivity and decreased radial diffusivity. In addition, the averaged FA of the cluster in this region correlated with behavioural measures as well as executive function in patients with ADHD.

Limitations

This study was limited by its cross-sectional design and small sample size. The cluster size of the significant result was small.

Conclusion

Our findings suggest that white matter abnormalities within the limbic network could be part of the neural underpinning of behavioural problems and executive dysfunction in patients with ADHD.     

Attentional functions in children and adolescents with attention-deficit/hyperactivity disorder with and without comorbid tic disorder

Summary Although the coexistence of attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) is common, the nature of association is yet not fully understood. Thus, the aim of the present study was to explore attentional dysfunction in children with pure ADHD compared to children with comorbid ADHD + TD. Three groups of 20 children each, aged 8–15 years with either ADHD, ADHD + chronic tic disorder or Tourette syndrome (ADHD + TD) and a healthy control group were compared in their performance on three computerized attention tasks. Tasks of sustained attention, selective attention and interference control were employed. In addition, parental ratings of ADHD symptom severity and behaviour problems were obtained. Both clinical groups were rated as equally inattentive, however, externalising symptoms were more severe in the ADHD group. Objective measures of attentional performance revealed differences between the groups: whereas the ADHD group was markedly impaired in sustaining attention and selective attention/inhibitory control, the ADHD + TD group only showed marginal deficits in selective attention/inhibitory control. Possible explanations for the superior performance of the comorbid group are discussed: In particular, the results may indicate that in some patients, the tic disorder produces behavioural symptoms of ADHD, but not the broad neurocognitive deficits that usually are associated with ADHD. Alternatively, compensatory neural mechanisms of TD patients may result in a better neuropsychological performance of comorbid patients relative to patients suffering from pure ADHD. Correspondence: Ellen Greimel, Child Neuropsychology Section, Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Aachen, 52074 Aachen, Germany     

Executive functioning among Finnish adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE: The present study examined cognitive functioning in a population sample of adolescents with and without attention-deficit/hyperactivity disorder (ADHD) from the Northern Finland Birth Cohort 1986. METHOD: The sample consisted of 457 adolescents ages 16 to 18 who were assessed using a battery of cognitive tasks. Performance according to diagnostic group (control, behavior disorder, and ADHD) and sex was compared. Then, the effect of executive function deficit (EFD) was assessed by diagnostic group status on behavioral and cognitive measures. RESULTS: When compared to non-ADHD groups, adolescents with ADHD exhibited deficits on almost all of the cognitive measures. The behavior disorder group obtained scores that were generally intermediate between the ADHD and control groups, but exhibited deficits in intelligence and executive function similar to the ADHD group. Approximately half the ADHD sample had EFD; however, the type and presence of EFDs were not differentially related to cognitive performance as a function of diagnosis. CONCLUSIONS: These findings indicate that EFDs are more frequent in ADHD than control or behavior disorder groups. EFDs are a general risk factor for poor cognitive functioning across multiple domains, irrespective of diagnostic status.     

Psychoeducational interventions for children and adolescents with attention-deficit/hyperactivity disorder

Children with attention-deficit/hyperactivity disorder (ADHD) are at risk for impaired functioning in most areas related to school success. Despite the benefits of psychostimulants and other medications to alleviate problem behaviors associated with ADHD, these therapies are unable to completely ameliorate behavior problems for all children with this disorder. Additionally, whereas pharmacologic therapies do impact behavioral functioning they have not been shown to improve academic achievement. Therefore, attention needs to be directed toward psychoeducational interventions and their ability to increase the successful functioning of children with ADHD. The purpose of this article is to highlight some of the most prominent and empirically validated classroom intervention strategies for children with ADHD. Additionally, this article discusses the importance of choosing psychoeducational interventions based on functional assessment data. Finally, this article describes progress monitoring strategies that should be used to determine the efficacy of intervention strategies.     

Internet addiction and attention-deficit / hyperactivity disorder symptoms in adolescents with autism spectrum disorder

AimSeveral studies have reported that internet addiction (IA) is more prevalent in adolescents with autism spectrum disorder (ASD). However, the characteristics of ASD adolescents with IA are unclear. The objective of this study was to investigate the prevalence of IA in ASD adolescents, and compare the characteristics between the IA and the non-IA groups in adolescents with ASD.MethodsThe study included 55 participants who were outpatients at Ehime University Hospital and Ehime Rehabilitation Center for Children in Japan, aged 10–19 years, diagnosed with ASD. Patients and their parents answered several questionnaires including the Young's Internet Addiction Test (IAT), Strengths and Difficulties Questionnaire (SDQ), Autism Spectrum Quotient (AQ), and Attention Deficit Hyperactivity Disorder Rating Scale-IV (ADHD-RS).ResultsBased on the total IAT score, 25 out of 55 participants were classified as having IA. Although there were no significant differences in AQ and Intelligence Quotient, the higher scores of ADHD symptoms in SDQ and ADHD-RS were observed in the IA group than the non-IA group. The IA group used portable games more often than the non-IA group.ConclusionThe ADHD symptoms were strongly associated with IA in ASD adolescents. More intensive prevention and intervention for IA are needed especially for the ASD adolescents with ADHD symptoms.     

Empathic accuracy in adolescents with autism spectrum disorders and adolescents with attention-deficit/hyperactivity disorder

In research on theory of mind (ToM) in individuals with an autism spectrum disorder (ASD) mainly static mind-reading tasks were used. In this study both a static (Eyes Test) and a more naturalistic (empathic accuracy task) ToM measure were used to investigate the perspective taking abilities of adolescents with ASD (n = 13), adolescents with attention-deficit/hyperactivity disorder (ADHD; n = 13) and typically developing adolescents (n = 18). An innovative aspect concerns the standard stimulus tapes of the empathic accuracy task, which showed interactions between dyads of one adolescent with ADHD and one adolescent without ADHD. In this way, we were able to compare the ‘readability’ of the thoughts and feelings of adolescents with and without ADHD. The results clearly demonstrate the impairment in perspective taking abilities of adolescents with ASD, both on the static and naturalistic mind-reading task. Moreover, the empathic accuracy task seems to be a useful and promising method to assess ToM abilities in adolescents, with or without clinical problems. Finally, thoughts and feelings of target persons with ADHD seemed to be less easy to read than the thoughts and feelings of typically developing target persons.     

Familial clustering of symptoms and disruptive behaviors in multiplex families with attention-deficit/hyperactivity disorder

OBJECTIVE: To examine familial clustering of attention-deficit/hyperactivity disorder (ADHD), ADHD subtypes, symptoms, and oppositional behaviors in affected sibling pairs (ASPs) and their parents. METHOD: One hundred thirty-two ASPs, ranging in age from 5 to 25 years and ascertained through clinic and volunteer referrals, were examined for DSM-IV ADHD subtypes, oppositional defiant disorder (ODD), and conduct disorder (CD) with the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL). Two hundred fifty-six parents in these families were assessed by means of the SADS-Lifetime version, Modified for the Study of Anxiety Disorders, Updated for DSM-IV (SADS-LA-IV), and the Behavioral Disorders supplement of the K-SADS-PL to determine ADHD, ODD, and CD. RESULTS: Fifty-five percent of families ascertained through an ASP have at least one parent with a lifetime diagnosis of ADHD. The frequency of ADHD in at least one parent was higher in families with at least one affected girl (63%) than in families with only affected boys (45%) (p = .02). There was no evidence that affected siblings or parents within ASP families showed similar patterns of ADHD symptoms, such as ADHD subtype classification. In contrast, CD significantly clustered in ASP families. CONCLUSIONS: The sex difference in prevalence of ADHD among ASPs is consistent with a model of inheritance in which girls require a greater loading of familial influences to develop ADHD. The lack of familial clustering of ADHD symptoms within ASP families suggests that hyperactive and inattentive symptoms reflect common familial underpinnings and not unique familial effects. In contrast, CD seems to reflect unique familial underpinnings distinct from those underlying ADHD.     

Effect of trait anxiety on cognitive test performance in adolescents with and without attention-deficit/hyperactivity disorder

Introduction: Attention-deficit/hyperactivity disorder (ADHD) and anxiety are frequently comorbid disorders associated with different types of abnormal performance on neuropsychological tests. Although some studies have shown that comorbid anxiety alters ADHD test performance, results inconsistently show both improvements and worsening of different abilities, with failures to replicate across different anxiety disorders. Alternatively, trait anxiety may reflect a more stable influence on ADHD test performance than various diagnosable anxiety disorders. Method: To better understand the possible enhancing or deleterious effects of anxiety on ADHD cognitive impairments, this study examined the effect of individual differences in trait anxiety measured by the Multidimensional Anxiety Scale for Children (MASC) on a battery of computerized, rapid-performance tests measuring attention and impulsivity-related performance in 98 Diagnostic and Statistical Manual of Mental Disorders–Fourth Edition (DSM–IV) Combined-Subtype ADHD adolescents and 123 healthy controls. It was hypothesized that trait anxiety would attenuate response inhibition and attention deficits in ADHD. Results: ADHD-diagnosed adolescents with higher trait anxiety performed better on indices of sustained attention, reaction time, and motor variability, and had altered overall test-performance strategy, while response inhibition was affected in both ADHD and non-ADHD. Conclusions: This study provides the first evidence that pathological levels of anxiety are not needed to see differences in ADHD neuropsychological test performance. Instead, mildly elevated trait anxiety confers a protective influence by reducing the degree of impairment seen in ADHD. These findings suggest that better performing ADHD adolescents might have optimized levels of cortical arousal, and raise new questions about how best to identify the neurobiological substrates responsible for the beneficial effects.     

Six-week open-label reboxetine treatment in children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE: This open-label study assessed the effectiveness of reboxetine, a selective norepinephrine reuptake inhibitor, in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) resistant to a previous methylphenidate trial. METHOD: Thirty-one child and adolescent outpatients, aged 8 to 18 (mean age, 11.7; SD = 2.87) years, diagnosed with ADHD were enrolled in a 6-week open-label study. Assessments included rater-administered scales (DSM-IV ADHD Scale; Clinical Global Impressions Scale), parent-administered scales (the Abbreviated Conners Rating Scale), and self-administered-scales for the evaluation of depressive (Children's Depression Inventory) and anxiety (the Revised Children's Manifest Anxiety Scale) symptoms. Reboxetine was initiated and maintained at a dose of 4 mg/day. RESULTS: A significant decrease in ADHD symptoms, on all scales measured, was noted. Adverse effects were relatively mild and transient. The most common adverse effects were drowsiness/sedation and gastrointestinal complaints. CONCLUSIONS: The results of the current open-label study suggest the effectiveness of reboxetine in the treatment of ADHD in methylphenidate-resistant children and adolescents. Double-blind, placebo-, and active comparator-controlled studies are indicated to rigorously test the efficacy of reboxetine in ADHD.