The influence of comorbid oppositional defiant disorder on white matter microstructure in attention-deficit/hyperactivity disorder

Functional and structural connectivity of the subregions of the amygdala in ADHD children with or without ODD

OBJECTIVES

The current study aimed to investigate the structural and functional connectivity of the subregions of the amygdala in children with Attention Deficit/Hyperactivity Disorder (ADHD) only or comorbid with Oppositional Defiant Disorder (ODD).

METHODS

A total of 354 children with ADHD-only, 161 children with ADHD and ODD (ADHD + ODD), and 100 healthy controls were enrolled. The Child Behavior Checklist (CBCL) and the Behavior Rating Inventory of Executive Function (BRIEF) were filled out by caregivers. Analysis of covariance (ANCOVA) was performed to test group-wise differences in these behavioral measures. A subsample comprising 209 participants underwent a resting-state functional MRI scan and a diffusion-weighted imaging (DWI) scan. Functional connectivity and structural connectivity were calculated using bilateral subregions of the Amygdala as seeds. Between-group voxel-wise comparisons were conducted.

RESULTS

The ADHD + ODD group had more anxious/depressed moods, more delinquent and aggressive behaviors, more emotional control problems, and more inhibition deficits than the ADHD-only group (all PBonferroni-corrected < 0.05). Compared with the control and ADHD + ODD groups, the ADHD-only group displayed increased FC strength between the amygdala subregions and the left caudate, left putamen, and frontal cortex. Regarding structural connectivity (SC), the ADHD-only group demonstrated higher streamline density in the left internal capsule, corpus callosum, and the right superior corona radiata. The altered SC was associated with emotional problems in children with ADHD, while the altered FC was associated with other ADHD-related clinical features.

CONCLUSIONS

Altered structural and functional connectivity of the subregions of the amygdala in children with ADHD compared with their healthy counterparts were respectively associated with ADHD-related behavioral and emotional problems.

CLINICAL TRIAL NUMBER

not applicable.

Sex differences in psychiatric comorbidities of attention-deficit/hyperactivity disorder among children, adolescents, and adults: A nationwide population-based cohort study

This cross-sectional, nationwide, population-based study aimed to elucidate sex differences in psychiatric comorbidities of Attention-deficit/hyperactivity disorder (ADHD) across children, adolescents, and adults. We analyzed data from Taiwan's comprehensive healthcare database, including 112,225 individuals diagnosed with ADHD, categorized by age (0-12, 13-18, ≥18 years) and sex. Psychiatric comorbidities were assessed using ICD-9-CM codes, focusing on age and sex-specific prevalence. Among the cohort, 83.50% were children (0-12 years) presenting primarily with learning disabilities and tics, while adolescents (13-18 years; 11.88%) had higher instances of oppositional defiant and conduct disorders. In adults (≥18 years; 4.62%), the prevalence of anxiety, depression, bipolar disorder, and substance misuse was notably higher. Males under 18 predominantly had ADHD, whereas females exhibited increased vulnerability to emotional disorders. In adulthood, males showed greater susceptibility to most psychiatric comorbidities, except sleep disorders. The study highlights the evolving nature of ADHD-related psychiatric comorbidities across different life stages, with distinct sex-based patterns. The transition from childhood to adulthood sees an increased prevalence of various psychiatric conditions, particularly impacting adult males. These findings underscore the need for age- and sex-specific therapeutic approaches in ADHD management. The cultural context of the study necessitates further research in diverse populations for broader applicability of the findings.

The effect of a single dose of methylphenidate on attention in children and adolescents with ADHD and comorbid Oppositional Defiant Disorder

The co-occurrence Oppositional Defiant Disorder (ODD) in children and adolescents with Attention Deficit Hyperactivity Disorder (ADHD) has been associated to difficulties in regulating adverse states, elevated functional impairment, deficits in Executive Functions and high risk for psychopathology. Recent studies have shown that ODD is a negative predictor of a positive response to methylphenidate (MPH) treatment for ADHD symptoms in children and adolescents and that patients with a diagnosis of comorbid ADHD and ODD are less likely to respond favorably to pharmacological treatment with MPH. We conducted a naturalistic study to understand the clinical characteristics of drug-naïve children and adolescents with ADHD that influence the response to MPH by measuring the effect on attention. Specifically, we investigated whether a single dose of MPH differently affects the performance of 53 children and adolescents with ADHD with or without ODD comorbidity. In addition, participant characteristics such as symptom severity, functional impairment, and associated behavioral and emotional symptoms at baseline were examined to better understand what aspects affect the response to MPH. We found that a single dose of MPH improved the attention of children and adolescents with ADHD without ODD more than those with comorbid ADHD and ODD, resulting in reduced reaction times. Our findings indicated that children and adolescents with comorbid ADHD and ODD and those with ADHD alone did not exhibit differences in measures of attention prior to taking MPH, nor in demographic variables (age, intelligence quotient, gender), clinical characteristics related to symptom severity, and adaptive behaviors. However, we observed differences between the two groups in certain behavioral aspects, including the Dysregulation Profile and disruptive behaviors. Assessing symptoms in combination with the presence of ADHD can be beneficial in determining which individuals would derive the greatest benefits from treatment.

Different executive function impairments in medication-naïve children with attention-deficit/hyperactivity disorder comorbid with oppositional defiant disorder and conduct disorder

The impairment of executive functions (EFs) in attention-deficit/hyperactivity disorder (ADHD) might vary from one individual to another, indicating high heterogeneity. Comorbidity may contribute to this heterogeneity. Disruptive behavior disorders (DBD), including oppositional defiant disorder (ODD) and conduct disorder (CD), is the most common comorbidity in ADHD. Although many studies suggest that ADHD with CD (ADHD_CD+) and ADHD with ODD (ADHD_ODD+) should be treated differently, little research has attempted to separate these two disorders when studying the EFs and brain imaging of ADHD with DBD (ADHD_DBD+). Thus, based on our ongoing research in ADHD, we have now recruited a large sample size of medication-naïve children to obtain estimates of neurocognitive function and functional brain networks. We found no EF impairment in ADHD_CD+ patients compared with healthy controls (HCs). Correlation analysis showed that more severe CD symptoms were associated with better EFs. The mediation analysis revealed that the relationship between CD symptoms and inhibition function was mediated by the functional connectivity (FC) of SMN(L) - DMN(R) in the younger group. The study suggested that ADHD_CD+ and ADHD_ODD+ are different in their EF impairment. The comorbidity of CD may not worsen the impairments and might even improve EF performance within ADHD individuals.

Multidimensional brain-age prediction reveals altered brain developmental trajectory in psychiatric disorders

Brain-age prediction has emerged as a novel approach for studying brain development. However, brain regions change in different ways and at different rates. Unitary brain-age indices represent developmental status averaged across the whole brain and therefore do not capture the divergent developmental trajectories of various brain structures. This staggered developmental unfolding, determined by genetics and postnatal experience, is implicated in the progression of psychiatric and neurological disorders. We propose a multidimensional brain-age index (MBAI) that provides regional age predictions. Using a database of 556 individuals, we identified clusters of imaging features with distinct developmental trajectories and built machine learning models to obtain brain-age predictions from each of the clusters. Our results show that the MBAI provides a flexible analysis of region-specific brain-age changes that are invisible to unidimensional brain-age. Importantly, brain-ages computed from region-specific feature clusters contain complementary information and demonstrate differential ability to distinguish disorder groups (e.g., depression and oppositional defiant disorder) from healthy controls. In summary, we show that MBAI is sensitive to alterations in brain structures and captures distinct regional change patterns that may serve as biomarkers that contribute to our understanding of healthy and pathological brain development and the characterization and diagnosis of psychiatric disorders.

The potential shared brain functional alterations between adults with ADHD and children with ADHD co-occurred with disruptive behaviors

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Many previous studies have shown that the comorbid status of disruptive behaviour disorders (DBD) was a predictor for ADHD persistence into adulthood. However, the brain mechanisms underlying such a relationship remain unclear. Thus, we aim to investigate whether the brain functional alteration in adults with ADHD could also be detected in children with ADHD co-occurring with disruptive behaviours from both quantitative and categorical dimensions.

METHODS

A total of 172 children with ADHD (cADHD), 98 adults with ADHD (aADHD), 77 healthy control children (cHC) and 40 healthy control adults (aHC) were recruited. The whole-brain spontaneous fluctuations in brain activity of each participant were recorded using functional near-infrared spectroscopy (fNIRS), and the functional connectivities (FCs) were calculated. We first compared the FC differences between aADHD and aHC. Then, for the regions with significantly abnormal FCs in aADHD, we further compared these features between cADHD and cHC. In addition, the correlation between these FCs and the conduct disorder (CD)/oppositional defiant disorder (ODD) symptoms were analysed in cADHD. Moreover, to render the results readily interpretable, we compared the FC differences among ADHD_CD-, subthreshold ADHD_CD+ and cHC groups, and among ADHD_ODD-, ADHD_ODD+ and cHC groups. Finally, we repeated the above analysis after controlling for other comorbidities and core symptoms to diminish the potential confounding effects.

RESULTS

We found that compared with aHC, aADHD showed significantly increased FCs in the VN, DMN, SMN, and DAN. The aforementioned abnormal FCs were also detected in cADHD, however, in an opposite orientation. Notably, these abnormal FCs were positively correlated with CD symptoms. Finally, the subthreshold ADHD_CD+ group even exhibited a tendency of adult-like increased FCs compared with the cHC. The results held after controlling for other comorbidities and core symptoms.

CONCLUSION

This study provides functional neuroimaging evidence that CD might be a risk factor for ADHD persistence into adulthood. Our work highlights the importance of differentiating ADHD_CD+ from ADHD and inspiring further understanding of brain development in ADHD.

White matter microstructural integrity correlates of emotion dysregulation in children with ADHD: A diffusion imaging tractography study

BACKGROUND

Emotion dysregulation (ED) is prevalent in youths with attention-deficit hyperactivity disorder (ADHD) and causes more social impairment and poor adaptive function. Alterations in the integrity of white matter (WM) tracts might have important implications for affective processing related to ED. However, little is known about the WM correlates underpinning ED in ADHD.

METHODS

Using diffusion spectrum image tractography, we obtained generalized fractional anisotropy (GFA) values of 76 WM tracts in 77 children with ADHD and 105 typically developing controls (TDC). ED severity was defined by the dysregulation profile from the child behavior checklist. Canonical correlation analysis (CCA) was performed to identify modes that relate WM microstructural property to ED severity and cognitive measures.

RESULTS

The application of CCA identified one significant mode (r = 0.638, FWE-corrected p = 0.046) of interdependencies between WM property patterns and diagnosis, ADHD total symptom levels, dysregulation by diagnosis interaction, and full-scale intellectual quotient (FIQ). GFA values of 19 WM tracts that were linked to affective-processing, sensory-processing and integration, and cognitive control circuitry were positively correlated with ED severity in TDC but negatively correlated with ED severity in ADHD. ADHD symptom severity and diagnosis were negatively associated with the GFA patterns of this set of tract bundles. In contrast, FIQ was positively correlated with this set of tract bundles.

CONCLUSIONS

This study used the CCA to show that children with ADHD and TDC had distinct multivariate associations between ED severity (diagnosis by ED interaction) and microstructural property in a set of WM tracts. These tracts interconnect the cortical regions that are principally involved in emotion processing, integration, and cognitive control in multiple brain systems. The WM microstructure integrity impairment might be an essential correlate of emotion dysregulation in ADHD.

Heterogeneity in brain functional changes of cognitive processing in ADHD across age: A systematic review of task-based fMRI studies

This review aims to establish the cognitive processing of patients with attention-deficit hyperactive disorder (ADHD) across age. Functional magnetic resonance imaging (fMRI) studies on children and adult populations were conducted, thus delineating deficits that could have been maintained and ameliorated across age. This allowed for the examination of the correlation between patterns of brain activation and the corresponding development of functional heterogeneity in ADHD. A systematic literature search of fMRI studies on ADHD was conducted using the PubMed and Scopus electronic databases based on PRISMA guidelines. References and citations were verified in Scopus database. The present study has identified 14 studies on children, 16 studies on adults, and one study on both populations of ADHD consisting of 1371 participants. Functional heterogeneity is present in ADHD across age, which can manifest either as different brain activation patterns, intra-subject variability, or both. This is shown in the increased role of the frontal regions and the specialized network in adults with ADHD from inefficient non-specific activation in childhood. Functional heterogeneity may manifest when delayed maturation is insufficient to normalize frontal lobe functions.

Association of self-regulation with white matter correlates in boys with and without autism spectrum disorder

Previous studies demonstrated distinct neural correlates underpinning impaired self-regulation (dysregulation) between individuals with autism spectrum disorder (ASD) and typically developing controls (TDC). However, the impacts of dysregulation on white matter (WM) microstructural property in ASD and TDC remain unclear. Diffusion spectrum imaging was acquired in 59 ASD and 62 TDC boys. We investigated the relationship between participants’ dysregulation levels and microstructural property of 76 WM tracts in a multivariate analysis (canonical correlation analysis), across diagnostic groups. A single mode of brain-behavior co-variation was identified: participants were spread along a single axis linking diagnosis, dysregulation, diagnosis-by-dysregulation interaction, and intelligence to a specific WM property pattern. This mode corresponds to diagnosis-distinct correlates underpinning dysregulation, which showed higher generalized fractional anisotropy (GFA) associated with less dysregulation in ASD but greater dysregulation in TDC, in the tracts connecting limbic and emotion regulation systems. Moreover, higher GFA of the tracts implicated in memory, attention, sensorimotor processing, and perception associated with less dysregulation in TDC but worse dysregulation in ASD. No shared WM correlates of dysregulation between ASD and TDC were identified. Corresponding to previous studies, we demonstrated that ASD and TDC have broad distinct white matter microstructural property underpinning self-regulation.

Fixel-Based Diffusion Magnetic Resonance Imaging Reveals Novel Associations Between White Matter Microstructure and Childhood Aggressive Behavior

BACKGROUND

Childhood aggression has been linked to white matter abnormalities, but research has been inconsistent with regard to both regions of alterations and directionality of the associations. We examined white matter microstructure correlates of aggression using a novel diffusion imaging analysis technique, fixel-based analysis, which leverages connectivity and crossing-fiber information to assess fiber bundle density.

METHODS

The sample included 70 children with aggressive behavior and 25 healthy control children without aggressive behavior. Aggression was measured by the parent-rated Aggressive Behavior scale of the Child Behavior Checklist. Fixel-based analysis was conducted at the whole-brain and region-of-interest levels, including the uncinate fasciculus, inferior longitudinal fasciculus, fornix, cingulum bundle, and genu, body, isthmus, and splenium of the corpus callosum.

RESULTS

Whole-brain analysis of covariance revealed that children with aggressive behavior, relative to control children, had lower fiber density in a cluster of limbic and cortical pathways, including the inferior fronto-occipital fasciculus, fornix, middle cerebellar peduncle, and superior thalamic radiations (familywise error-corrected p < .01), and had higher fiber density in the corpus callosum (body and splenium) (familywise error-corrected p < .05). Region-of-interest analyses showed decreased fiber density in cingulum bundles associated with aggression. These effects were independent of age, sex, IQ, symptoms of attention-deficit/hyperactivity disorder, medications, and head motion. In children with aggressive behavior, co-occurring callous-unemotional traits and anxiety did not moderate the association between aggression and white matter density.

CONCLUSIONS

Diminished white matter density in pathways connecting limbic and cortical regions is associated with childhood aggression. Abnormal interhemispheric connectivity via corpus callosum may also reflect a potential neural mechanism involved in aggression.

Development of the frontal lobe

Development of the frontal lobe is critical to acquisition, execution, and control of a wide range of functions, from basic motor response to complex decision-making. These functions are influenced by contingency-based (e.g., reward and response-cost/punishment) feedback that is mediated through the adaptive integration of fronto-subcortical neural circuitry. The frontal lobe manages incoming information and chooses the appropriate action based on one's goals in a particular context. This aspect of frontal function, while only one component, is crucial to development and maintenance of approach and avoidance behavior central to all human (and animal) behavior. Furthermore, disruptions in fronto-subcortical circuitry governing motivated behavior appear to contribute to a range of developmental disorders, including attention-deficit/hyperactivity disorder (ADHD), and confer vulnerability for psychopathology more broadly. The particular deficits that manifest in altered behavior depend upon the specific circuitry that is compromised due to the functional specificity of distinct regions of the frontal lobe and its interconnections with subcortical structures. Neurobiologic models of motivated behavior provide a valuable framework for characterizing developmental disorders from a transdiagnostic dimensional systems perspective. Improved characterization of approach and avoidance motivation across neurodevelopmental disorders has the potential to inform the development of novel interventions and personalized medicine.

Comorbidity prevalence and treatment outcome in children and adolescents with ADHD

Although ADHD comorbidity has been widely studied, some issues remain unsolved. This multicenter observational study aims to examine comorbid psychiatric disorders in a clinical sample of newly diagnosed, treatment naïve children and adolescents with and without ADHD and, to compare treatment efficacy based on the type of comorbidity. We performed an analysis of the medical records of patients identified from the Regional ADHD Registry database, enrolled in 18 ADHD centers in the 2011-2016 period. 1919 of 2861 subjects evaluated (67%) met the diagnostic criteria for ADHD: 650 (34%) had only ADHD, while 1269 (66%) had at least one comorbid psychiatric disorder (learning disorders, 56%; sleep disorders, 23%; oppositional defiant disorder, 20%; anxiety disorders, 12%). Patients with ADHD of combined type and with severe impairment (CGI-S ≥5) were more likely to present comorbidity. 382 of 724 (53%) followed up patients improved after 1 year of treatment. ADHD with comorbidity showed greater improvement when treated with combined interventions or methylphenidate alone. Specifically, combined treatment showed significant superiority for ADHD with learning disorders (ES 0.66) and ODD (ES 0.98), lower for ADHD with sleep or anxiety disorders. Training intervention alone showed only medium efficacy (ES 0.50) for ADHD and learning disorders. This study was the first describing comorbidity patterns of ADHD in Italy, confirming, in a multicenter clinical setting, that ADHD is more often a complex disorder. Findings highlight important diagnostic, therapeutic, and service organization aspects that should be broadly extended to ensure an appropriate and homogenous ADHD management.