Clinical and neurobiological factors in the management of treatment refractory attention-deficit hyperactivity disorder

The effectiveness of a single session of mindfulness-based cognitive training on cardiac vagal control and core symptoms in children and adolescents with attention-deficit/hyperactivity disorder (ADHD): a preliminary randomized controlled trial

This study examined the effectiveness of a mindfulness-based intervention (MBI) on Conners' continuous performance test scores (CPTs), cardiac vagal control (CVC) assessed by vagally mediated heart rate variability (HRV), and mood in children and adolescents with ADHD. We conducted a randomized controlled trial (RCT) recruiting 70 children and adolescents (M age 11.03, SD 2.78) with a clinical diagnosis of ADHD, which were allocated to either 1 session of mindfulness cognitive training, or an active control condition and were examined at baseline, post-treatment and 4-week follow-up. See clinicaltrials.gov: NCT04316832. There was a significant main effect of time on the primary outcomes measured by CPT scores of attention-related problems (omission errors, reaction time) and hyperactivity-impulsivity (commission errors). However, time-by-group interaction did not achieve statistical significance for commission errors and hit RT, indicating that the changes over time in these outcomes were not significantly different between the MBI and Control conditions. In addition, there was a significant time-by-group interaction for omission errors. Relative to control, MBI resulted in a small (d = 0.011) non-statistically significant reduction in omission errors post-treatment. Furthermore, there were no significant differences in detectability. Secondary outcomes were CVC and mood. A small treatment effect on CVC (d = 0.37) was observed; there was a slight increase in vagally mediated HRV measure post-treatment. There were no significant differences in mood improvement over time between conditions. One brief session of MBI effectively enhances CVC but does not significantly improve CPT scores of attention-related problems and hyperactivity-impulsivity or mood in children with ADHD.Clinicaltrials.gov: NCT04316832.

Dissection of neuronal circuits underlying sustained attention with the five-choice serial reaction time task

Attention deficits are common in psychiatric and neurological disorders. The transdiagnostic nature of impaired attention suggests a common set of underlying neural circuits. Yet, there are no circuit-based treatments such as non-invasive brain stimulation currently available due to the lack of sufficiently delineated network targets. Therefore, to better treat attentional deficits, a comprehensive functional dissection of neural circuits underlying attention is imperative. This can be achieved by taking advantage of preclinical animal models and well-designed behavioral assays of attention. The resulting findings in turn can be translated to the development of novel interventions with the goal of advancing them to clinical practice. Here we show that the five-choice serial reaction time task has greatly facilitated the study of the neural circuits underlying attention in a well-controlled setting. We first introduce the task and then focus on its application in preclinical studies on sustained attention, especially in the context of state-of-the-art neuronal perturbations.

Effectiveness of cognitive behavioural-based interventions for adults with attention-deficit/hyperactivity disorder extends beyond core symptoms: A meta-analysis of randomized controlled trials

OBJECTIVES

To provide an updated systematic review of randomized controlled studies for the efficacy of cognitive behavioural therapy (CBT) in treating adults with attention-deficit/hyperactivity disorder (ADHD).

DESIGN

Meta-analysis.

METHODS

PROSPERO registration: CRD42021273633. The methods used aligned with the PRISMA guidelines. Database searches identified CBT treatment outcome studies eligible for conducted meta-analysis. Treatment response was summarized by calculating the standardized mean differences for changes in outcome measures for adults with ADHD. Measures included core and internalizing symptoms and were assessed on the basis of self-reporting and investigator evaluation.

RESULTS

Twenty-eight studies met the inclusion criteria. This meta-analysis indicates that CBT for adults with ADHD was effective in reducing both core and emotional symptoms. Decreases in depression and anxiety were predicted by the reduction of core ADHD symptoms. An increase in self-esteem and quality of life were also observed for adults with ADHD who were received CBT. Adults who received either individual or group therapy significantly exhibited a greater reduction of symptoms than those who received active control intervention, received treatment as usual, or were on the treatment waitlist. Traditional CBT was equally effective in reducing core ADHD symptoms but outperformed other CBT approaches in reducing emotional symptoms among adults with ADHD.

CONCLUSIONS

This meta-analysis offers cautiously optimistic support for the efficacy of CBT in treating adults with ADHD. The additional reduction of emotional symptoms demonstrates the potential of CBT in adults with ADHD who are at higher risk for depression and anxiety comorbidities.

Interventions for ADHD in childhood and adolescence: A systematic umbrella review and meta-meta-analysis

There are several meta-analyses of treatment effects for children and adolescents with attention deficit hyperactivity disorder (ADHD). The conclusions of these meta-analyses vary considerably. Our aim was to synthesize the latest evidence of the effectiveness of psychological, pharmacological treatment options and their combination in a systematic overview and meta-meta-analyses. A systematic literature search until July 2022 to identify meta-analyses investigating effects of treatments for children and adolescents with ADHD and ADHD symptom severity as primary outcome (parent and teacher rated) yielded 16 meta-analyses for quantitative analyses. Meta-meta-analyses of pre-post data showed significant effects for pharmacological treatment options for parent (SMD = 0.67, 95% CI 0.60 to 0.74) and teacher ADHD symptom ratings (SMD = 0.68, 95% CI 0.54 to 0.82) as well as for psychological interventions for parent (SMD = 0.42, 95% CI 0.33 to 0.51) and teacher rated symptoms (SMD = 0.25, 95% CI 0.12 to 0.38). We were unable to calculate effect sizes for combined treatments due to the lack of meta-analyses. Our analyses revealed that there is a lack of research on combined treatments and for therapy options for adolescents. Finally, future research efforts should adhere to scientific standards as this allows comparison of effects across meta-analyses.

Animal Models of Childhood Exposure to Lead or Manganese: Evidence for Impaired Attention, Impulse Control, and Affect Regulation and Assessment of Potential Therapies

Behavioral disorders involving attention and impulse control dysfunction, such as ADHD, are among the most prevalent disorders in children and adolescents, with significant impact on their lives. The etiology of these disorders is not well understood, but is recognized to be multifactorial, with studies reporting associations with polygenic and environmental risk factors, including toxicant exposure. Environmental epidemiological studies, while good at establishing associations with a variety of environmental and genetic risk factors, cannot establish causality. Animal models of behavioral disorders, when properly designed, can play an essential role in establishing causal relationships between environmental risk factors and a disorder, as well as provide model systems for elucidating underlying neural mechanisms and testing therapies. Here, we review how animal model studies of developmental lead or manganese exposure have been pivotal in (1) establishing a causal relationship between developmental exposure and lasting dysfunction in the domains of attention, impulse control, and affect regulation, and (2) testing the efficacy of specific therapeutic approaches for alleviating the lasting deficits. The lead and manganese case studies illustrate how animal models can advance knowledge in ways that are not possible in human studies. For example, in contrast to the Treatment of Lead Poisoned Children (TLC) human clinical trial evaluating succimer chelation efficacy to improve cognitive functioning in lead-exposed children, our developmental lead exposure animal model showed that succimer chelation can produce lasting cognitive benefits if chelation sufficiently reduces brain lead levels. In addition, this study revealed that succimer treatment in the absence of lead exposure produces lasting cognitive dysfunction, highlighting potential risks of chelation in off-label uses, such as the treatment of autistic children without a history of lead exposure. Our animal model of developmental manganese exposure has demonstrated that manganese can cause lasting attentional and sensorimotor deficits, akin to an ADHD-inattentive behavioral phenotype, thereby providing insights into the role of environmental exposures as contributors to ADHD. These studies have also shown that oral methylphenidate (Ritalin) can fully alleviate the deficits produced by early developmental Mn exposure. Future work should continue to focus on the development and use of animal models that appropriately recapitulate the complex behavioral phenotypes of behavioral disorders, in order to determine the mechanistic basis for the behavioral deficits caused by developmental exposure to environmental toxicants, and the efficacy of existing and emerging therapies.

The Use of Brexpiprazole Combined With a Stimulant in Adults With Treatment-Resistant Attention-Deficit/Hyperactivity Disorder

BACKGROUND

This is the first controlled pharmacologic study in either adults or children with uncomplicated, treatment-resistant attention-deficit/hyperactivity disorder (ADHD). This study augmented stimulant therapy with the atypical antipsychotic brexpiprazole. The Food and Drug Administration preapproved primary outcome measure (Conners' Adult ADHD Rating Scale [CAARS]) showed no drug-placebo differences. Often studies showing no efficacy on the prestudy, defined primary outcome variable go unpublished. While this is decried, publishing studies with equivocal results remains rare. This reanalysis highlights trends in secondary measures having implications for treatment and research regarding treatment resistant ADHD.

METHODS

Initially, 559 stimulant-naive and 174 prior stimulant nonresponders received methylphenidate osmotic-release oral system, dexmethylphenidate hydrochloride, lisdexamfetamine, or mixed amphetamine salts. After 5 weeks, 168 stimulant-naive patients and 68 prior stimulant nonresponders who failed treatment were randomized to brexpiprazole or placebo in a 2:1 ratio while the remaining were on the stimulant. Outcome was measured with the CAARS, Montgomery-Asberg Depression Rating Scale, Beck Depression Inventory, Clinical Global Impression, and the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS). The WRAADDS contains 2 factors: attention and emotional dysregulation.

RESULTS

Stimulant-naive patients showed no improvement with adjunctive brexpiprazole. Prior stimulant nonresponders displayed no brexpiprazole effect on the CAARS, Montgomery-Asberg Depression Rating Scale, or Beck Depression Inventory. In contrast, the WRAADDS detected a trend in treatment benefit, primarily through emotional dysregulation symptoms. Adverse effects on brexpiprazole and placebo were equivalent.

CONCLUSIONS

Brexpiprazole might be effective in ADHD adults who are nonresponders to 2 or more stimulants. Future trials in treatment-resistant ADHD should use a 1:1 randomization and use a measure of ADHD symptoms that includes emotional dysregulation.

Personalization of pharmacological treatments for ADHD: Why it is advisable and possible options to achieve it

Abstract:

Attention-deficit hyperactivity disorder is a neurodevelopmental disorder diagnosed primarily in children, although it is also present in adults. Patients present inattention, impulsivity, and hyperactivity symptoms that create difficulties in their daily lives. Pharmacological treatment with stimulants or non-stimulants is used most commonly to reduce ADHD symptoms. Although generally effective and safe, pharmacological treatments have different effects among patients, including lack of response and adverse reactions. The reasons for these differences are not fully understood, but they may derive from the highly diverse etiology of ADHD. Strategies to guide optimal pharmacological treatment selection on the basis of individual patients’ physiological markers are being developed. In this review, we describe the main pharmacological ADHD treatments used and their main drawbacks. We present alternatives under study that would allow the customization of pharmacological treatments to overcome these drawbacks and achieve more reliable improvement of ADHD symptoms.

Trigeminal nerve stimulation: a recently approved treatment approach in attention deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) with its high prevalence is a growing area of concern and research, whereas exact underlying pathophysiology remains unknown. Behavioral therapy and multiple medications include methylphenidate, atomoxetine, and amphetamines while trigeminal nerve stimulator (TNS) is the first medical device in ADHD with FDA approval. The aim of this article is to evaluate the latest studies in this field.

Noradrenergic genes polymorphisms and response to methylphenidate in children with ADHD: A systematic review and meta-analysis

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is the most common childhood-onset neurodevelopmental disorder, and methylphenidate (MPH) is considered one of the first-line medicine for ADHD. Unfortunately, this medication is only effective for some children with ADHD. This meta-analysis was conducted to evaluate whether noradrenergic gene polymorphisms impact the efficacy of MPH in children with ADHD.

METHODS

Candidate gene studies published in English until March 1, 2020, were identified through literature searches on PubMed, Web of Science, and Embase. Data were pooled from individual clinical trials considering MPH pharmacogenomics. According to the heterogeneity, the odds ratio and mean differences were calculated by applying fixed-effects or random-effects models.

RESULTS

This meta-analysis includes 15 studies and 1382 patients. Four polymorphisms of the NET gene (rs5569, rs28386840, rs2242446, rs3785143) and 2 polymorphisms of the α2A-adrenergic receptor gene (ADRA2A) gene (MspI and DraI) were selected for the analysis. In the pooled data from all studies, T allele carriers of the rs28386840 polymorphism were significantly more likely to respond to MPH (P < .001, ORTcarriers = 2.051, 95% confidence interval [CI]:1.316, 3.197) and showed a relationship with significantly greater hyperactive-impulsive symptoms improvement (P < .001, mean difference:1.70, 95% CI:0.24, 3.16). None of the ADRA2A polymorphisms correlated significantly with MPH response as a whole. However, G allele carriers of the MspI polymorphism showed a relationship with significantly inattention symptoms improvement (P < .001, mean difference:0.31, 95% CI: 0.15, 0.47).

CONCLUSION

Our meta-analysis results indicate that the noradrenergic gene polymorphisms may impact MPH response. The NET rs28386840 is linked to improved MPH response in ADHD children. And the ADRA2A MspI is associated with inattention symptom improvements. Further investigations with larger samples will be needed to confirm these results.Registration: PROSPERO (no. CRD42021265830).

The "VIP-ADHD trial": Does brain arousal have prognostic value for predicting response to psychostimulants in adult ADHD patients?

EEG studies have shown that adult ADHD patients have less stable brain arousal regulation than age and gender matched controls. Psychostimulants have brain arousal stabilising properties evident in EEG patterns. The aim of this study was to investigate whether the stability of brain arousal regulation has prognostic value in predicting response to methylphenidate therapy in adult ADHD patients. In an open-label, single-arm, multi-centre, confirmatory trial, 121 adult ADHD patients were recruited and 112 qualified for the full analysis set. All participants received an initial dose of 20 mg extended release methylphenidate at baseline. After a titration phase of up to 4 weeks, patients remained on a weight-based target dose of extended release methylphenidate for 4 weeks. Using the Vigilance Algorithm Leipzig (VIGALL 2.1), we assessed brain arousal regulation before the treatment with methylphenidate, based on a 15-min EEG at quiet rest recorded at baseline. Using automatic stage-classification of 1 s segments, we computed the mean EEG-vigilance (indexing arousal level) and an arousal stability score (indexing arousal regulation). The primary endpoint was the association between successful therapy, defined by a 30% reduction in CAARS, and stable/unstable brain arousal. 52 patients (46%) showed an unstable brain arousal regulation of which 23% had therapy success. In the stable group, 35% had therapy success, implying an absolute difference of 12 percentage points (95% CI -5 to 29, p = 0.17) in the direction opposite to the hypothesized one. There were no new findings regarding the tolerability and safety of extended release methylphenidate therapy.

What Do Meta-Analyses Have to Say About the Efficacy of Neurofeedback Applied to Children With ADHD? Review of Previous Meta-Analyses and a New Meta-Analysis

Objective: We reviewed previously published meta-analyses of neurofeedback applied to children with ADHD and conducted a new meta-analysis of randomized controlled trials (RCTs) that updates previous results and incorporates methodological modifications. Method: Searches were carried out through PubMed, Sage, PsycINFO, SpringerLink, and Psicodoc. We used Hedges' (adjusted) g and a random-effects model. To assess heterogeneity, Q and I² were calculated. We performed different analyses depending on the control groups, ADHD symptoms, pre- and/or posttreament data used and symptom evaluator. Results: We reviewed seven meta-analyses, and 17 studies were incorporated into the meta-analysis. RCTs support the efficacy of neurofeedback applied to ADHD when most proximal evaluators assess symptoms. Neurofeedback significantly improves inattention symptoms when possibly blinded evaluators assess symptoms. The preliminary results suggest that stimulant medication is more effective than neurofeedback. Conclusion: New RCTs that establish links between ADHD symptom measurements, subjects' learning after neurofeedback, and neurophysiological measures could improve the quality of the conclusions.

Regional brain volume predicts response to methylphenidate treatment in individuals with ADHD

BACKGROUND

Despite the effectiveness of methylphenidate for treating ADHD, up to 30% of individuals with ADHD show poor responses to methylphenidate. Neuroimaging biomarkers to predict medication responses remain elusive. This study characterized neuroanatomical features that differentiated between clinically good and poor methylphenidate responders with ADHD.

METHODS

Using a naturalistic observation design selected from a larger cohort, we included 79 drug-naive individuals (aged 6-42 years) with ADHD without major psychiatric comorbidity, who had acceptable baseline structural MRI data quality. Based on a retrospective chart review, we defined responders by individuals' responses to at least one-month treatment with methylphenidate. A nonparametric mass-univariate voxel-based morphometric analysis was used to compare regional gray matter volume differences between good and poor responders. A multivariate pattern recognition based on the support vector machine was further implemented to identify neuroanatomical indicators to predict an individual's response.

RESULTS

63 and 16 individuals were classified in the good and poor responder group, respectively. Using the small-volume correction procedure based on the hypothesis-driven striatal and default-mode network masks, poor responders had smaller regional volumes of the left putamen as well as larger precuneus volumes compared to good responders at baseline. The machine learning approach identified that volumetric information among these two regions alongside the left frontoparietal regions, occipital lobes, and posterior/inferior cerebellum could predict clinical responses to methylphenidate in individuals with ADHD.

CONCLUSION

Our results suggest regional striatal and precuneus gray matter volumes play a critical role in mediating treatment responses in individuals with ADHD.

Z-Score Neurofeedback and Heart Rate Variability Training for Adults and Children with Symptoms of Attention-Deficit/Hyperactivity Disorder: A Retrospective Study

ADHD is a common condition that causes suffering for those affected and economic loss for society at large. The current standard treatment for ADHD includes stimulant medications, which are not effective for all patients, may include side effects, and can be non-medically misused. Z-score neurofeedback (NFB) and heart rate variability (HRV) biofeedback are alternative treatment strategies that have been associated with Attention-Deficit/Hyperactivity Disorder (ADHD) symptom improvement. We utilized a retrospective pre-post study design to quantify the change in clients' ADHD symptoms after combined NFB + HRV treatment (which included simultaneous z-score training at four sites). We also assessed whether relevant physiological measures changed in accordance with the protocol, which would be consistent with effective NFB + HRV training. Adults (n = 39) and children (n = 100) with Borderline or Clinical ADHD classifications by the Achenbach System of Empirically Based Assessment (ASEBA) received 30 sessions of NFB + HRV training. Measures were compared before and after treatment for the ASEBA, the Integrated Visual and Auditory Continuous Performance Test (IVA), ADHD medication use, HRV and breathing parameters, and quantitative electroencephalogram (QEEG) parameters. Average ASEBA Attention-Deficit/Hyperactive Problems score improved after treatment for adults and children (p < 0.0001), with Cohen effect sizes (dz) of -1.21 and -1.17, respectively. 87.2% of adults and 80.0% of children experienced improvements of a magnitude greater than or equal to the Minimal Clinically Important Difference. After treatment, 70.8% of adults and 52.8% of children who began in the ASEBA Clinical range, and 80.0% of adults and 63.8% of children who began in the ASEBA Borderline range, were classified in the Normal range. IVA scores also improved after treatment. Changes in HRV and breathing pattern after treatment were consistent with the protocol. QEEG parameters after treatment were closer to the age-based normative mean, which is consistent with effective z-score NFB training.

Predictive Value of Slow and Fast EEG Oscillations for Methylphenidate Response in ADHD

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder and is characterized by symptoms of inattention and/or hyperactivity and impulsivity. In the current study, we obtained quantitative EEG (QEEG) recordings of 51 children aged between 6 and 12 years before the initiation of methylphenidate treatment. The relationship between changes in the scores of ADHD symptoms and initial QEEG features (power/power ratios values) were assessed. In addition, the children were classified as responder and nonresponder according to the ratio of their response to the medication (>25% improvement after medication). Logistic regression analyses were performed to analyze the accuracy of QEEG features for predicting responders. The findings indicate that patients with increased delta power at F8, theta power at Fz, F4, C3, Cz, T5, and gamma power at T6 and decreased beta powers at F8 and P3 showed more improvement in ADHD hyperactivity symptoms. In addition, increased delta/beta power ratio at F8 and theta/beta power ratio at F8, F3, Fz, F4, C3, Cz, P3, and T5 showed negative correlations with Conners' score difference of hyperactivity as well. This means, those with greater theta/beta and delta/beta powers showed more improvement in hyperactivity following medication. Theta power at Cz and T5 and theta/beta power ratios at C3, Cz, and T5 have significantly classified responders and nonresponders according to the logistic binary regression analysis. The results show that slow and fast oscillations may have predictive value for treatment response in ADHD. Future studies should seek for more sensitive biomarkers.

Genetic associations between ADHD and dopaminergic genes (DAT1 and DRD4) VNTRs in Korean children

It is well known that dopaminergic genes affect the development of attention deficit hyperactivity disorder (ADHD) in various populations. Many studies have shown that variable number tandem repeats (VNTRs) located within the 3'-untranslated region of DAT1 and in exon 3 of DRD4 are associated with ADHD development; however, these results were inconsistent. Therefore, we investigated the genetic association between two VNTRs and ADHD in Korean children. We determined the VNTRs using PCR. We examined genotype and allele frequency differences between the experimental and control groups, along with the odds ratios, using Chi square and exact tests. We observed a significant association between the children with ADHD and the control group in the 10R/10R genotype of DAT1 VNTRs (p = 0.025). In addition, the 11R allele of DAT1 VNTRs showed a higher frequency in the control group than in the ADHD group (p = 0.023). Also, the short repeat (without 11R) and long repeat alleles (including 11R) were associated with ADHD (p < 0.05). The analysis of DRD4 VNTRs revealed that the 2R allele is associated with ADHD (p = 0.025). A significant result was also observed in long and short repeats (p < 0.05). Additionally, ADHD subtypes showed that the DRD4 VNTRs are associated with combined and hyperactive-impulsive subtype groups (p < 0.05). Therefore, our results suggest that DAT1 VNTRs and DRD4 VNTRs play a role in the genetic etiology of ADHD in Korean children.