Parsing heterogeneity in attention-deficit hyperactivity disorder using EEG-based subgroups.

Background: Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous condition for which multiple efforts to characterize brain state differences are underway. The objective of this study was to identify distinct subgroups of resting electroencephalography (EEG) profiles among children with and without ADHD and subsequently provide extensive clinical characterization of the subgroups.

Methods: Latent class analysis was used with resting state EEG recorded from a large sample of 781 children with and without ADHD (N = 620 ADHD, N = 161 Control), aged 6-18 years old.

A parietal biomarker for ADHD liability: as predicted by the distributed effects perspective model of ADHD.

Background: We previously hypothesized that poor task-directed sensory information processing should be indexed by increased weighting of right hemisphere (RH) biased attention and visuo-perceptual brain functions during task operations and have demonstrated this phenotype in ADHD across multiple studies, using multiple methodologies. However, in our recent distributed effects model of ADHD, we surmised that this phenotype is not ADHD specific, but rather more broadly reflective of any circumstance that disrupts the induction and maintenance of an emergent task-directed neural architecture. Under this view, increased weighting of RH-biased attention and visuo-perceptual brain functions is expected to generally index neurocognitive sets that are not optimized for task-directed thought and action, and when durable expressed, liability for ADHD.

Community-Based Mindfulness Program for Disease Prevention and Health Promotion: Targeting Stress Reduction.

Purpose: Poorly managed stress leads to detrimental physical and psychological consequences that have implications for individual and community health. Evidence indicates that U.S.

Randomised controlled pilot trial of mindfulness training for stress reduction during pregnancy.

This randomised controlled pilot trial tested a six-week mindfulness-based intervention in a sample of pregnant women experiencing high levels of perceived stress and pregnancy anxiety. Forty-seven women enrolled between 10 and 25 weeks gestation were randomly assigned to either a series of weekly Mindful Awareness Practices classes (n = 24) with home practice or to a reading control condition (n = 23). Hierarchical linear models of between-group differences in change over time demonstrated that participants in the mindfulness intervention experienced larger decreases from pre-to post-intervention in pregnancy-specific anxiety and pregnancy-related anxiety (PRA) than participants in the reading control condition.

Characterization of the theta to beta ratio in ADHD: identifying potential sources of heterogeneity.

Objective: The goal of this study is to characterize the theta to beta ratio (THBR) obtained from electroencephalogram (EEG) measures, in a large sample of community and clinical participants with regard to (a) ADHD diagnosis and subtypes, (b) common psychiatric comorbidities, and (c) cognitive correlates.

Method: The sample includes 871 participants (595 youth and 276 adults) with and without ADHD. All participants underwent extensive assessment, including semistructured diagnostic interviews, cognitive testing, and EEG recording.

Sex-specific influence of DRD2 on ADHD-type temperament in a large population-based birth cohort.

Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder with a significant public-health impact. Previously, we described a candidate gene study in a population-based birth cohort that demonstrated an association with ADHD-affected males and the dopamine receptor D2 (DRD2). The current study evaluates potential associations of dopamine receptor genes and Cloninger temperament traits within this same sample.

Genome-wide association study of intelligence: additive effects of novel brain expressed genes.

Objective: The purpose of the present study was to identify common genetic variants that are associated with human intelligence or general cognitive ability.

Method: We performed a genome-wide association analysis with a dense set of 1 million single-nucleotide polymorphisms (SNPs) and quantitative intelligence scores within an ancestrally homogeneous family sample of 656 individuals with at least one child affected by attention-deficit/hyperactivity disorder (ADHD).

Results: Haplotype trend regression analysis with sliding four-SNP windows identified haplotypes of genome-wide significance in genes involved in synaptic signaling (KIF16B; p = 1.

Genome-wide analysis of copy number variants in attention deficit hyperactivity disorder: the role of rare variants and duplications at 15q13.3.

Objective: Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable psychiatric disorder. Because of its multifactorial etiology, however, identifying the genes involved has been difficult. The authors followed up on recent findings suggesting that rare copy number variants (CNVs) may be important for ADHD etiology.

Genome-wide copy number variation study associates metabotropic glutamate receptor gene networks with attention deficit hyperactivity disorder.

Attention deficit hyperactivity disorder (ADHD) is a common, heritable neuropsychiatric disorder of unknown etiology. We performed a whole-genome copy number variation (CNV) study on 1,013 cases with ADHD and 4,105 healthy children of European ancestry using 550,000 SNPs. We evaluated statistically significant findings in multiple independent cohorts, with a total of 2,493 cases with ADHD and 9,222 controls of European ancestry, using matched platforms.

Brain growth rate abnormalities visualized in adolescents with autism.

Autism spectrum disorder is a heterogeneous disorder of brain development with wide ranging cognitive deficits. Typically diagnosed before age 3, autism spectrum disorder is behaviorally defined but patients are thought to have protracted alterations in brain maturation. With longitudinal magnetic resonance imaging (MRI), we mapped an anomalous developmental trajectory of the brains of autistic compared with those of typically developing children and adolescents.

Atypical EEG beta asymmetry in adults with ADHD.

Background: Abnormal brain laterality (ABL) is well established in ADHD. However, its clinical specificity and association to cognitive and clinical symptoms is not yet understood. Previous studies indicate increased right hemisphere (RH) contribution in both ADHD and reading impaired samples.

Familial clustering and DRD4 effects on electroencephalogram measures in multiplex families with attention deficit/hyperactivity disorder.

Objective: The current study tests electroencephalogram (EEG) measures as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD) by examining sibling and parent-offspring similarity, familial clustering with the disorder, and association with the dopamine receptor D4 (DRD4) candidate gene.

Method: The sample consists of 531 participants (191 parents and 340 children) from 132 multiplex families with ADHD who participated in a larger genetics study. All members of the families underwent extensive assessment including semi-structured diagnostic interviews and EEG recording.

On genome-wide association studies for family-based designs: an integrative analysis approach combining ascertained family samples with unselected controls.

Large numbers of control individuals with genome-wide genotype data are now available through various databases. These controls are regularly used in case-control genome-wide association studies (GWAS) to increase the statistical power. Controls are often "unselected" for the disease of interest and are not matched to cases in terms of confounding factors, making the studies more vulnerable to confounding as a result of population stratification.

ADHD familial loading and abnormal EEG alpha asymmetry in children with ADHD.

Objective: Abnormal brain laterality (ABL) is indicated in ADHD. ADHD and brain laterality are heritable. Genetic factors contributing to lateralization of brain function may contribute to ADHD.

A candidate gene analysis of methylphenidate response in attention-deficit/hyperactivity disorder.

Objective: This study examines the potential role of candidate genes in moderating treatment effects of methylphenidate (MPH) in attention-deficit/hyperactivity disorder (ADHD).

Method: Eighty-two subjects with ADHD aged 6 to 17 years participated in a prospective, double-blind, placebo-controlled, multiple-dose, crossover titration trial of immediate release MPH three times daily. The subjects were assessed on a variety of parent and clinician ratings and a laboratory math test.

Mindfulness and attention deficit hyperactivity disorder.

Attention deficit hyperactivity disorder (ADHD) is a disorder characterized by attentional difficulties. Mindfulness is a receptive attention to present experience. Both ADHD and mindfulness are associated with attention and personality.

Social functioning difficulties in ADHD: association with PDD risk.

Although social difficulties are a common feature of Attention-Deficit Hyperactivity Disorder (ADHD), little is known about the diversity of social problems, their etiology, or their relationship to disorders of social behavior, such as autism or Pervasive Developmental Disorder (PDD). In 379 children and adolescents with ADHD, social functioning was assessed using the Child Behavior Checklist (Achenbach, 1991). Factor analysis and structural equation modeling revealed two factors that we labeled Peer Rejection and Social Immaturity.

Atypical alpha asymmetry in adults with ADHD.

Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e.

Cortical activity patterns in ADHD during arousal, activation and sustained attention.

Objective: The goal of the present study is to test whether there are Attention-Deficit Hyperactivity Disorder (ADHD)-related differences in brain electrical activity patterns across arousal, activation and vigilance states.

Method: The sample consists of 80 adults (38 with ADHD and 42 non-ADHD controls) who were recruited for a family study on the genetics of ADHD. Patterns of cortical activity were measured using electroencephalography (EEG) during baseline and sustained attention conditions and compared according to ADHD diagnostic status.

Meta-analysis of genome-wide linkage scans of attention deficit hyperactivity disorder.

Genetic contribution to the development of attention deficit hyperactivity disorder (ADHD) is well established. Seven independent genome-wide linkage scans have been performed to map loci that increase the risk for ADHD. Although significant linkage signals were identified in some of the studies, there has been limited replications between the various independent datasets.

Rethinking a right hemisphere deficit in ADHD.

Introduction: Early observations from lesion studies suggested right hemisphere (RH) dysfunction in ADHD. However, a strictly right-lateralized deficit has not been well supported. An alternatively view suggests increased R > L asymmetry of brain function and abnormal interhemispheric interaction.

CBCL pediatric bipolar disorder profile and ADHD: comorbidity and quantitative trait loci analysis.

Objective: The pediatric bipolar disorder profile of the Child Behavior Checklist (CBCL-PBD), a parent-completed measure that avoids clinician ideological bias, has proven useful in differentiating patients with attention-deficit/hyperactivity disorder (ADHD). We used CBCL-PBD profiles to distinguish patterns of comorbidity and to search for quantitative trait loci in a genomewide scan in a sample of multiple affected ADHD sibling pairs.

Method: A total of 540 ADHD subjects ages 5 to 18 years were assessed with the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version and CBCL.

Cognitive functioning in affected sibling pairs with ADHD: familial clustering and dopamine genes.

Background: This paper examines familiality and candidate gene associations of cognitive measures as potential endophenotypes in attention-deficit/hyperactivity disorder (ADHD).

Methods: The sample consists of 540 participants, aged 6 to 18, who were diagnosed with ADHD from 251 families recruited for a larger genetic study of ADHD. All members of the family underwent psychiatric interviews and children were administered a large battery of cognitive tasks.

Association of the cannabinoid receptor gene (CNR1) with ADHD and post-traumatic stress disorder.

Attention deficit hyperactivity disorder (ADHD) is a highly heritable disorder affecting some 5-10% of children and 4-5% of adults. The cannabinoid receptor gene (CNR1) is a positional candidate gene due to its location near an identified ADHD linkage peak on chromosome 6, its role in stress and dopamine regulation, its association with other psychiatric disorders that co-occur with ADHD, and its function in learning and memory. We tested SNP variants at the CNR1 gene in two independent samples-an unselected adolescent sample from Northern Finland, and a family-based sample of trios (an ADHD child and their parents).