Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Subtype/Presentation: Research Progress and Translational Studies

Differences in the Interleukin Profiles in Inattentive ADHD Prepubertal Children Are Probably Related to Conduct Disorder Comorbidity

Inflammatory cytokines are involved in attention deficit hyperactivity disorder (ADHD), a highly prevalent neurodevelopmental disorder. To quantify the baseline levels of pro- and anti-inflammatory cytokines and their changes after methylphenidate (MPH), a total of 31 prepubertal children with ADHD were recruited and subclassified into only two ADHD presentations-ADHD attention deficit (n = 13) or ADHD combined (n = 18). The children were also screened for oppositional defiant conduct disorder (ODCD) and anxiety disorder. Blood samples were drawn at 09:00 and after 4.63 ± 1.87 months of treatment. Four pro-inflammatory cytokines (interleukin-1beta (IL-1β), IL-5, IL-6, tumor necrosis factor-alpha (TNF-α)) and three anti-inflammatory cytokines (IL-4, IL-10, IL-13) were measured using a Luminex® assay. For statistics, a factorial analysis was performed in Stata 15.1. Overall, there were no statistically significant differences in the interleukin (IL) values induced by treatment. When grouped by presentation, the differences were present almost exclusively in ADHD-AD, usually with a profile opposite to that observed in ADHD-C, and with interactions between comorbid factors, with IL-1β (p = 0.01) and IL-13 (p = 0.006) being the ones reaching the greatest statistical significance. These differences are probably related to the ODCD factor, and they disappear after treatment. In conclusion, the changes observed in cytokine levels in prepubertal children only in the ADHD-AD presentation are probably related to comorbidities (specifically ODCD) and are mitigated after treatment.

Neural correlates of inattention in adults with ADHD

In the last two decades, numerous magnetic resonance imaging (MRI) studies have examined differences in cortical structure between individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) and healthy controls. These studies primarily emphasized alterations in gray matter volume (GMV) and cortical thickness (CT). Still, the scientific literature is notably scarce in regard to investigating associations of cortical structure with ADHD psychopathology, specifically inattention within adults with ADHD. The present study aimed to elucidate neurobiological underpinnings of inattention beyond GMV and CT by including cortical gyrification, sulcal depth, and fractal dimension. Building upon the Comparison of Methylphenidate and Psychotherapy in Adult ADHD Study (COMPAS), cortical structure parameters were investigated using 141 T1-weighted anatomical scans of adult patients with ADHD. All brain structural analyses were performed using the threshold-free cluster enhancement (TFCE) approach and the Computational Anatomy Toolbox (CAT12) integrated into the Statistical Parametric Mapping Software (Matlab Version R2021a). Results revealed significant correlations of inattention in multiple brain regions. Cortical gyrification was negatively correlated, whereas cortical thickness and fractal dimension were positively associated with inattention. The clusters showed widespread distribution across the cerebral cortex, with both hemispheres affected. The cortical regions most prominently affected included the precuneus, para-, pre-, and postcentral gyri, superior parietal lobe, and posterior cingulate cortex. This study highlights the importance of cortical alterations in attentional processes in adults with ADHD. Further research in this area is warranted to elucidate intricacies of inattention in adults with ADHD to potentially enhance diagnostic accuracy and inform personalized treatment strategies.

Developmental exposure to 17-α-hydroxyprogesterone caproate disrupts decision-making in adult female rats: A potential role for a dopaminergic mechanism

The synthetic progestin, 17α-hydroxyprogesterone caproate (17-OHPC), is administered to pregnant individuals at risk for preterm birth and is likely transferred from mother to fetus. Yet, there is little information regarding the potential effects of 17-OHPC administration on behavioral and neural development in offspring. In rats, neonatal 17-OHPC exposure altered dopaminergic fiber distribution and density in the prelimbic medial prefrontal cortex (mPFC) in neonates and adolescents, respectively. Additionally, neonatal 17-OHPC exposure in male rats increased response omissions in a delay discounting task of impulsive decision-making. Because developmental 17-OHPC exposure has differential effects in males and females, investigating the effects of 17-OHPC on impulsive decision-making in female rats is necessary. The present study tested the effects of developmental 17-OHPC exposure (P1-P14) in a delay discounting task in which female rats chose between a small immediate reward and a larger delayed (0, 15 30, or 45 s) reward. 17-OHPC-exposed females made more omissions than controls. There was no effect of 17-OHPC on large reward preference nor on response time, and omissions were similar during both free- and forced-choice trials. The present study also aimed to investigate the neural mechanisms underlying omissions in 17-OHPC-exposed female rats. The dopamine transporter inhibitor, methylphenidate (MPH), was administered prior to delay discounting testing. MPH treatment did not reduce omissions in 17-OHPC-exposed females. If anything, MPH increased omissions in control females nearly fourfold during the longest delays. These results suggest that developmental 17-OHPC exposure increased omissions without affecting impulsivity or slowing decision-making. Furthermore, omissions may be regulated, at least in part, by dopaminergic mechanisms.

Development and validation of a nomogram prediction model for ADHD in children based on individual, family, and social factors

OBJECTIVES

A reliable, user-friendly, and multidimensional prediction tool can help to identify children at high risk for ADHD and facilitate early recognition and family management of ADHD. We aimed to develop and validate a risk nomogram for ADHD in children aged 3-17 years in the United States based on clinical manifestations and complex environments.

METHODS

A total of 141,356 cases were collected for the prediction model. Another 54,444 cases from a new data set were utilized for performing independent external validation. The LASSO regression was used to control possible variables. A final risk nomogram for ADHD was established based on logistic regression, and the discrimination and calibration of the established nomogram were evaluated by bootstrapping with 1000 resamples.

RESULTS

A final risk nomogram for ADHD was established based on 13 independent predictors, including behavioral problems, learning disabilities, age, intellectual disabilities, anxiety symptoms, gender, premature birth, maternal age at childbirth, parent-child interaction patterns, etc. The C-index of this model was 0.887 in the training set, and 0.862 in the validation set. Internal and external validation proved that the model was reliable.

CONCLUSIONS

A nomogram, a statistical prediction tool that assesses individualized ADHD risk for children is helpful for the early identification of children at high risk for ADHD and the construction of a conceptual model of society-family-school collaborative diagnosis, treatment, and management of ADHD.

The detect consensus report on Attention Deficit/Hyperactivity Disorder and its management among Turkish children and adolescents (Detect: consensus report on ADHD among Turkish youth)

Attention Deficit/Hyperactivity Disorder (ADHD) is one of the most common and heritable neurodevelopmental disorders which may last through the life-span. A consensus report on diagnosis and management of ADHD among Turkish youth was prepared previously. However, the participants as well as the management options were rather limited and developments in the past decade necessitated a revision and update of the consensus. Therefore, this review aims to summarize the consensus among Child and Adolescent Psychiatrists from Türkiye on the nature and management of pediatric ADHD. For those aims, the etiology of ADHD, diagnostic and evaluation process, epidemiology, developmental presentations, differential diagnoses and comorbidities, course/outcome and pharmacological as well as non-pharmacological management options were reviewed and suggestions for clinical practice are presented. Since ADHD is a chronic disorder with wide-ranging effects on functionality that is frequently accompanied by other mental disorders, a multidimensional therapeutic approach is recommended. However, since the disorder has neurobiological basis, pharmacotherapy represents the mainstay of treatment. Additional therapies may include psychosocial therapy, behavioral therapy, school-based therapeutic approaches, and family education. This review provides recommendations for ADHD at the national and global levels. It contains information about ADHD that will contribute to and facilitate clinicians' decision-making processes. It is advisable to consider this guideline in clinical practice.

Development of a human-analogue, 3-symptom domain Dog ADHD and Functionality Rating Scale (DAFRS)

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours that are similar to human attention-deficit/hyperactivity disorder (ADHD) symptoms. Based on standard questionnaire methods in humans, we aimed to develop and validate a detailed, psychometrically improved tool to assess owner views on relevant dog behaviours. We modified available questionnaires by adding items that allow for separate analysis of impulsivity, and items on functional impairment. We collected data from 1168 owners for different validation steps of the new questionnaire and, similarly to assessment of humans where teachers also evaluate as an expert control, we collected data from dog trainers. Exploratory and confirmatory factor analysis revealed 3 factors: inattention (IA), hyperactivity (H) and impulsivity (I), corresponding to all three human symptom dimensions in dogs. Test-retest analyses showed excellent agreement between measurements for all factors. Similarly to findings with humans, trainer-owner rating comparisons showed fair (IA) to moderate (H, I) agreement. As in humans, greater ADHD scores were associated with greater functional impairment scores. We suggest that in dogs, similarly to humans, parallel examination of (extreme) ADHD and functional impairment scores could help distinguish diagnosable individuals, after further validation of the questionnaire using a relevant behaviour test.

Hippocampal dentate gyri proteomics reveals Wnt signaling involvement in the behavioral impairment in the THRSP-overexpressing ADHD mouse model

Children with attention-deficit/hyperactivity disorder (ADHD) often struggle with impaired executive function, temporal processing, and visuospatial memory, hallmarks of the predominantly inattentive presentation (ADHD-PI), subserved by the hippocampus. However, the specific genes/proteins involved and how they shape hippocampal structures to influence ADHD behavior remain poorly understood. As an exploratory tool, hippocampal dentate gyri tissues from thyroid hormone-responsive protein overexpressing (THRSP OE) mice with defining characteristics of ADHD-PI were utilized in proteomics. Integrated proteomics and network analysis revealed an altered protein network involved in Wnt signaling. Compared with THRSP knockout (KO) mice, THRSP OE mice showed impaired attention and memory, accompanied by dysregulated Wnt signaling affecting hippocampal dentate gyrus cell proliferation and expression of markers for neural stem cell (NSC) activity. Also, combined exposure to an enriched environment and treadmill exercise could improve behavioral deficits in THRSP OE mice and Wnt signaling and NSC activity. These findings show new markers specific to the ADHD-PI presentation, converging with the ancient and evolutionary Wnt signaling pathways crucial for cell fate determination, migration, polarity, and neural patterning during neurodevelopment. These findings from THRSP OE mice support the role of Wnt signaling in neurological disorders, particularly ADHD-PI presentation.

Long-term treatment of adult ADHD in a naturalistic setting: clinical predictors of attrition, medication choice, improvement, and response

Objectives: The aim of this study was to identify clinical predictors of treatment attrition, medication choice, improvement and response to pharmacotherapy in adult attention-deficit/hyperactivity disorder (ADHD). Methods: 150 ADHD patients were enrolled and naturalistically followed-up for at least 4 months. Conners' Adult ADHD Rating Scales-Observer: Screening Version (CAARS-O:SV) were used to measure ADHD severity. Results: 58 subjects (38.7%) were lost at follow-up, while 75 (50%) completed follow-up assessment, on average after 26.05 ± 11.99 weeks; 35 were treated with atomoxetine (ATX) and 40 with methylphenidate (MPH). Treatments were moderately effective (d = 0.72) and 37 patients (49.3%) were responders (≥30% CAARS-O:SV decrease). Patients lost at follow-up had lower inattentive symptoms, less generalized anxiety and family history of bipolar disorder, more amphetamine use disorder than follow-up completers. Compared to ATX-treated subjects, MPH-treated patients had greater severity of hyperactivity/impulsivity and were more frequently diagnosed with alcohol use disorder. While MPH and ATX showed similar efficacy, more pronounced improvements were observed in patients with combined ADHD, anxiety and substance use disorders. ADHD severity and comorbid substance use positively predicted response. Conclusions: Consensus-based hierarchical treatment of ADHD comorbidity is not consistently supported. Comorbid anxiety, mood and substance use disorders should not discourage the treatment of adult ADHD.

Response inhibition in children with different subtypes/presentations of attention deficit hyperactivity disorder: A near-infrared spectroscopy study

Background

Executive dysfunction in children with attention deficit hyperactivity disorder (ADHD) is thought to be closely related to the prefrontal cortex (PFC). However, there is controversy over the activation of the PFC in children with ADHD. Differences could be related to the subtype. Meanwhile, no study to date has used functional near-infrared spectroscopy (fNIRS) to explore the differences between subtypes. Thus, this study aimed to explore the activation of the PFC in children with different subtypes of ADHD during executive function task.

Methods

Participants in this study include typically developing (TD) children (n = 28), ADHD-predominantly inattentive (ADHD-PI) (n = 39) and ADHD-combined (ADHD-C) (n = 24). To examine the executive function of ADHD, the Go/No-go task is chosen to assess the response inhibition function. The activation of PFC in all participants during the Go/No-go task was recorded by fNIRS. Meanwhile, behavioral data were also recorded.

Results

Both TD and ADHD children activated the right PFC [middle frontal gyrus (MFG) and inferior frontal gyrus (IFG)] during response inhibition. However, the range and degree of activation differed among these groups. Compared with TD children, those with ADHD-PI had a smaller extent of activation in the right PFC, and those with ADHD-C only had a tendency to enhance activation. In addition, children with ADHD-PI and ADHD-C had impaired activation of the temporal gyrus. Besides, compared with ADHD-C and TD, those with ADHD-PI also had impaired activation of the right precentral gyrus (PG), and the supplementary motor area (SMA). Compared with ADHD-PI, ADHD-C showed decreased activation of the right MFG. The activation of Ch34 (BA44, rPFC) in children with ADHD-PI and ADHD-C was negatively correlated with their clinical symptoms.

Conclusion

The activation of the PFC in children with different subtypes of ADHD has both commonalities and differences. The degree of activation of the right PFC Ch34 in children with ADHD is negatively correlated with clinical symptoms. fNIRS could be served as a candidate hemodynamic biomarker for the diagnosis of ADHD.

Associations between Family Functioning and Symptoms of Attention-Deficit Hyperactivity Disorder (ADHD): A Cross-Sectional Study

Poor family functioning is linked with poor child ADHD symptoms. However, there are many dimensions of family functioning. Thus, this study aims to find the association between each dimension of family functioning and controlled ADHD symptoms in an Asian culture. This cross-sectional study involved caregivers of 113 Thai children with ADHD ages 4–16 years old who visited the Outpatient Department at Maharaj Nakorn Chiang Mai Hospital between October 2017 and March 2018. The caregivers completed the Chulalongkorn Family Inventory and the SNAP-IV Thai version. Logistic regression was used to examine each dimension of family functioning adjusting for potential confounders. In univariate analyses, six of the seven dimensions of family functioning were associated with controlled ADHD symptoms. In multivariate analyses, findings revealed that good family roles (aOR 7.48, 95% CI = 1.56 to 35.85, p = 0.01) and behavior control (aOR 2.56, 95% CI = 1.08 to 6.03, p = 0.03) were associated with controlled ADHD symptoms. In children with ADHD with poor symptom control, the assessment of family functioning could be helpful. Developing a more specific intervention for caregivers that promotes good family roles and behavioral control may be beneficial.

Caring for adolescents and young adults with attention-deficit/hyperactivity disorder in primary care: seizing opportunities to address youth mental health needs

PURPOSE OF REVIEW

To provide primary care providers (PCPs) with updated practical guidance around the assessment and management of attention-deficit/hyperactivity disorder (ADHD) in adolescents and young adults (AYA).

RECENT FINDINGS

Of the three different presentations of ADHD delineated in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), the Predominantly Inattentive presentation is the most common among AYA. Multiple rating scales exist to assist clinicians in identifying ADHD symptoms and monitoring treatment effects. Importantly, ADHD frequently persists into adulthood with negative impacts in many life domains if left untreated. It is important for PCPs to provide support for AYA as they transition to adulthood, as treatment adherence often drops sharply at that time, and, once treatment is discontinued, it is rarely restarted. Further, clinicians should be aware of the negative psychological, behavioral, and social impacts that COVID-19 has had on AYA with ADHD.

SUMMARY

AYA with ADHD often seek care first from PCPs. However, diagnosis and management of ADHD among AYA are challenging, and many clinicians feel ill-equipped, creating concern that many youth may go undiagnosed and untreated. Despite these long-standing challenges, recent advances have opened up critical opportunities for PCPs to proactively address ADHD in primary care settings and make a profound impact on youth as they seek to realize their full potential.

Novel Oppositional Defiant Disorder 6 Months After Traumatic Brain Injury in Children and Adolescents

OBJECTIVE

The investigators aimed to assess predictive factors of novel oppositional defiant disorder (ODD) among children and adolescents in the first 6 months following traumatic brain injury (TBI).

METHODS

Children ages 5-14 years who experienced a TBI were recruited from consecutive admissions to five hospitals. Testing of a biopsychosocial model that may elucidate the development of novel ODD included assessment soon after injury (baseline) of preinjury characteristics, including psychiatric disorders, adaptive function, family function, psychosocial adversity, family psychiatric history, socioeconomic status, injury severity, and postinjury processing speed (which may be a proxy for brain injury). MRI analyses were also conducted to examine potential brain lesions. Psychiatric outcome, including that of novel ODD, was assessed 6 months after the injury.

RESULTS

A total of 177 children and adolescents were recruited for the study, and 134 who were without preinjury ODD, conduct disorder, or disruptive behavior disorder not otherwise specified (DBD NOS) returned for the 6-month assessment. Of those who returned 6 months postinjury, 11 (8.2%) developed novel ODD, and none developed novel conduct disorder or DBD NOS. Novel ODD was significantly associated with socioeconomic status, preinjury family functioning, psychosocial adversity, and processing speed.

CONCLUSIONS

These findings show that an important minority of children with TBI developed ODD. Psychosocial and injury-related variables, including socioeconomic status, lower family function, psychosocial adversity, and processing speed, significantly increase risk for this outcome.

Performance on a modified signal detection task of attention is impaired in male and female rats following developmental exposure to the synthetic progestin, 17α-hydroxyprogesterone caproate

Based on evidence that the developing mesocortical dopamine pathway is sensitive to progestins, in the present study we tested the hypothesis that attention, a fundamental component of successful cognitive behavior, is disrupted by developmental exposure to the synthetic progestin, 17-α-hydroxyprogesterone caproate (17-OHPC). To assess attentional impairments, a modified signal detection task was utilized with three stimulus modalities: compound (light and tone), light alone, and tone alone, for four stimulus durations (2, 0.5, 0.25, 0.125 s). Adult rats were trained to push one lever if they detected the stimulus, and another lever if the stimulus was not presented. 17-OHPC animals were able to attend to the task, as evidenced by similar correct responses as controls. However, as the task became increasingly difficult at shorter durations, 17-OHPC animals made significantly more omissions compared to controls, suggesting that 17-OHPC treatment may disrupt attentional processes and/or delay response time. These findings add to the current body of literature demonstrating that exposure to 17-OHPC during development produces deficits in cognitive behavior in adulthood. These results may inform potential risks associated with 17-OHPC treatment in pregnant women with a history of preterm delivery who are commonly recipients of such treatment.

Droxidopa alters dopamine neuron and prefrontal cortex activity and improves attention-deficit/hyperactivity disorder-like behaviors in rats

Finding alternative treatments for attention-deficit/hyperactivity disorder (ADHD) is crucial given the safety and efficacy problems of current ADHD medications. Droxidopa, also known as L-threo-dihydroxyphenylserine (L-DOPS), is a norepinephrine prodrug that enhances brain norepinephrine and dopamine levels. In this study, we used electrophysiological tests to examine effects of L-DOPS on the prefrontal cortex (PFC) and dopamine neurons in the ventral tegmental area. We also conducted behavioral tests to assess L-DOPS' effects on ADHD-like behaviors in rats. In chloral hydrate-anesthetized rats, PFC local field potentials oscillated between the active, depolarized UP state and the hyperpolarized DOWN state. Mimicking the effect of d-amphetamine, L-DOPS, given after the peripheral amino acid decarboxylase inhibitor, benserazide (BZ), increased the amount of time the PFC spent in the UP state, indicating an excitatory effect of L-DOPS on PFC neurons. Like d-amphetamine, L-DOPS also inhibited dopamine neurons, an effect significantly reversed by the D2-like receptor antagonist raclopride. In the behavioral tests, BZ + L-DOPS improved hyperactivity, inattention and impulsive action of the adolescent spontaneously hypertensive rat (SHR/NCrl), well-validated animal model of the combined type of ADHD. BZ + L-DOPS also reduced impulsive choice and impulsive action of Wistar rats, but did not ameliorate the inattentiveness of Wistar Kyoto rats (WKY/NCrl), proposed model of the ADHD-predominantly inattentive type. In conclusion, L-DOPS produced effects on the PFC and dopamine neurons characteristic of drugs used to treat ADHD. BZ + L-DOPS ameliorated ADHD-like behaviors in rats suggesting its potential as an alternative ADHD treatment.