Attention deficit hyperactivity disorder (ADHD) is emblematic of unresolved heterogeneity in psychiatric disorders- the variation in biological, clinical, and psychological correlates that impedes ...progress on etiology. One approach to this problem is to characterize subgroups using measures rooted in biological or psychological theory, consistent with the National Institute of Mental Health's research domain criteria initiative. Within ADHD, a promising application involves using emotion trait profiles that can address the role of irritability as a complicating feature for ADHD. Here, a new sample of 186 children with ADHD was evaluated using community detection analysis to determine if meaningful subprofiles existed and if they replicated those previously identified. The new sample and a prior sample were pooled for evaluation of (a) method dependence, (b) longitudinal assessment of the stability of classifications, and (c) clinical prediction 2 years later. Three temperament profiles were confirmed within the ADHD group: one with normative emotional functioning ("mild"), one with high surgency ("surgent"), and one with high negative affect ("irritable"). Profiles were similar across statistical clustering approaches. The irritable group had the highest external validity: It was moderately stable over time and it enhanced prospective prediction of clinical outcomes beyond standard baseline indicators. The irritable group was not reducible to ADHD + oppositional defiant disorder, ADHD + disruptive mood dysregulation disorder, or other patterns of comorbidity. Among the negative affect domains studied, trait proneness to anger uniquely contributed to clinical prediction. Results extend our understanding of chronic irritability in psychiatric disorders and provide prospects for a fresh approach to assessing ADHD heterogeneity focused on the distinction between ADHD with and without anger/irritability.
Public Significance Statement
This work identifies a group of children with ADHD and irritable mood who are at increased risk for negative outcomes. Addition of a specifier in the ADHD diagnostic criteria based on the presence or absence of irritability could be considered.
Highlights • Gene set analyses (GSAs) will extend the knowledge gained from GWAS. • There is no consensus about the best way to perform GSA. • The wide variety of analysis methods makes it difficult ...to compare GSA results. • Steps must be taken to improve the interpretability and comparability of GSA.
Reviews salient emerging themes in the scientific literature related to identifying etiology and pathophysiology of ADHD. While bypassing the need for new treatment research, the review highlights ...three themes. First, recognition of the epigenetic effects is expected to revitalize the search for and mapping of early environmental influences on the development of ADHD. Second, neurobiological findings will have limited impact if not examined in the context of significant race and cultural variation in ADHD-related developmental processes, and in the context of rapidly changing social and technological contexts of children's development worldwide. Third, further examination of the phenotype and characterization of its dimensional and categorical structure remains a major need. Overall, the coming decades of etiology research on ADHD will be expected to capitalize on new scientific tools. The hope in the field is that new insights into fundamental prevention can emerge.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Before assigning full etiologic validity to a psycopathologic disorder, disease theory suggests that a causal dysfunction in a mechanism within the affect individuals must be identified. Existing ...theories on attention-deficit/hyperactivity disorder (ADHD) suggest such dysfunctions in cognitive, neuropsychological, or motivational processes in the child. To date, researchers have tested these theories by comparing groups with DSM-defined ADHD to children without ADHD. Using executive functioning as an illustration of an issue that exists across all such theories, this article describes substantial overlaps in the group performance data. Thus only a subgroup may have executive deficits. Noted are other supportive data suggesting multiple pathways to ADHD. The article explores implications and recommends that future theory and research give more consideration to the probability that only a subset of behaviorally defined children will have a deficit in a given neurocognitive mechanism believed to contribute to the disorder. Creation of a provisional set of criteria in DSM-V for defining an “executive deficit type” could stimulate research to validate the first etiologic subtype of ADHD and spur the development of more sophisticated causal models, which in the longer term may give clinicians ways to target and tailor treatments.
Objective: Identification of biomarkers is a priority for attention-deficit/hyperactivity disorder (ADHD). Studies have documented macrostructural brain alterations in ADHD, but few have examined ...white matter microstructure, particularly in preadolescent children. Given dramatic white matter maturation across childhood, microstructural differences seen in adolescents and adults with ADHD may reflect compensatory restructuring, rather than early neurophenotypic markers of the disorder. Method: Using tract-based spatial statistics, mean fractional anisotropy (FA) maps were created using diffusion tensor imaging. FA, mean diffusivity (MD), and associated axial and radial diffusivities were compared between 16 children with ADHD and 20 healthy children (age 7-9 years). Results: Youth with ADHD showed decreased FA in frontoparietal, frontolimbic, cerebellar, corona radiata, and temporo-occipital white matter compared with controls. In addition, ADHD was associated with lower MD in the posterior limb of the internal capsule and frontoparietal white matter and greater MD in frontolimbic white matter. Lower axial diffusion and/or higher radial diffusion were differentially observed for youth with ADHD in earlier versus later maturing areas of group FA/MD difference. Conclusions: This study suggests that, even prior to adolescence, ADHD represents a disorder of altered structural connectivity of the brain, characterized by distributed atypical white matter microstructure. In addition, later maturing frontolimbic pathways were abnormal in children with ADHD, likely due to delayed or decreased myelination, a finding not previously demonstrated in the adolescent or adult stages of the disorder. These results suggest that disruptions in white matter microstructure may play a key role in the early pathophysiology of ADHD. (Contains 2 tables and 1 figure.)
Objective: The objective of the study is to examine whether children aged 7 to 11 years with very well-characterized ADHD, recruited from the community, have a similar number of healthy lifestyle ...behaviors as compared with typically developing children from the same community. Method: Parents of children with (n = 184) and without (n = 104) ADHD completed a lifestyle questionnaire asking about water intake, sweetened beverage consumption, multivitamin/supplement use, reading, screen time, physical activity, and sleep. A lifestyle index was formed from these seven domains (0-7), and multivariable ordered logistic regression was used to examine the association of ADHD status and total healthy lifestyle behaviors. Results: Children with ADHD were almost twice as likely to have fewer healthy behaviors, even after adjustment for age, sex, intelligence quotient (IQ), ADHD medication use, household income, and four comorbid psychiatric disorders (odds ratio OR 95% confidence interval = 1.95 1.16, 3.30, p = .01). Conclusion: Future research is needed to assess the effects of a combined lifestyle intervention in this group.
Attention deficit hyperactivity disorder (ADHD) is widely theorized to stem from dysfunctional inhibitory processes. However, the definition of inhibition is imprecisely distinguished across ...theories. To clarify the evidence for this conception, the author relies on a heuristic distinction between inhibition that is under executive control and inhibition that is under motivational control (anxiety or fear). It is argued that ADHD is unlikely to be due to a motivational inhibitory control deficit, although suggestions are made for additional studies that could overturn that conclusion. Evidence for a deficit in an executive motor inhibition process for the ADHD combined type is more compelling but is not equally strong for all forms of executive inhibitory control. Remaining issues include specificity to ADHD, whether inhibitory problems are primary or secondary in causing ADHD, role of comorbid anxiety and conduct disorder, and functional deficits in the inattentive ADHD subtype.
Food elimination diets are defined and the history of their investigation in relation to attention-deficit/hyperactivity disorder (ADHD) is reviewed. After noting that a consensus has emerged that an ...elimination diet produces a small but reliable aggregate effect, the present review provides updated quantitative estimates of effect size and clinical response rates to elimination diets. It then highlights key issues that require research attention, in particular characterization of dietary responders. Finally, because some children may benefit, clinical guidelines at the present state of knowledge are summarized. It is concluded that updated trials of elimination diets are sorely needed for ADHD.
Executive Function in Adolescents with ADHD Martel, Michelle; Nikolas, Molly; Nigg, Joel T
Journal of the American Academy of Child and Adolescent Psychiatry,
11/2007, Letnik:
46, Številka:
11
Journal Article
Recenzirano
A study is conducted to determine the specificity of executive function weakness in attention-deficit/hyperactivity disorder (ADHD) during adolescence. Results suggest that executive function ...weakness in ADHD is specifically associated with symptoms of inattention-disorganization.
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