ADHD & Pharmacotherapy: Past, Present and Future: A Review of the Changing Landscape of Drug Therapy for Attention Deficit Hyperactivity Disorder

Conceptualizing adult ADHD with the DSM alternative model of personality disorder

Personality traits and personality disorders are related to ADHD and indicate dysfunction in clinical populations. The goals of this study were to examine how the DSM-5 Alternative Model of Personality Disorder (AMPD) a) indicates the presence of ADHD and b) communicates information about dysfunction over and above ADHD diagnosis. A sample of 330 adult psychiatric patients with and without ADHD (60% female; mean age 33 years) were assessed for ADHD symptoms, personality impairment, maladaptive personality traits, and functional life impairment domains. The maladaptive personality domain Disinhibition and particularly the lower order facet of Distractibility distinguished between individuals with psychiatric difficulties with and without ADHD. Distractibility is strongly related to the ADHD symptom dimension Inattentiveness, and Antagonism to Hyperactivity/impulsivity. General personality impairment augmented ADHD diagnosis in predicting life impairments. The AMPD has utility in ADHD assessments for diagnosis and prognosis.

Novel pharmacological targets for GABAergic dysfunction in ADHD

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopment disorder that affects approximately 5% of the population. The disorder is characterized by impulsivity, hyperactivity, and deficits in attention and cognition, although symptoms vary across patients due to the heterogenous and polygenic nature of the disorder. Stimulant medications are the standard of care treatment for ADHD patients, and their effectiveness has led to the dopaminergic hypothesis of ADHD in which deficits in dopaminergic signaling, especially in cortical brain regions, mechanistically underly ADHD pathophysiology. Despite their effectiveness in many individuals, almost one-third of patients do not respond to stimulant treatments and the long-term negative side effects of these medications remain unclear. Emerging clinical evidence is beginning to highlight an important role of dysregulated excitatory/inhibitory (E/I) balance in ADHD. These deficits in E/I balance are related to functional abnormalities in glutamate and Gamma-Aminobutyric Acid (GABA) signaling in the brain, with increasing emphasis placed on GABAergic interneurons driving specific aspects of ADHD pathophysiology. Recent genome-wide association studies (GWAS) have also highlighted how genes associated with GABA function are mutated in human populations with ADHD, resulting in the generation of several new genetic mouse models of ADHD. This review will discuss how GABAergic dysfunction underlies ADHD pathophysiology, and how specific receptors/proteins related to GABAergic interneuron dysfunction may be pharmacologically targeted to treat ADHD in subpopulations with specific comorbidities and symptom domains. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".

A Protective Role of Low Polygenic Risk Score in Healthy Individuals Carrying Attention-Deficit/Hyperactivity Disorder-Associated Copy Number Variations

BACKGROUND

Previous studies have implicated both rare copy number variations (CNVs) and common variants in liability for attention-deficit/hyperactivity disorder (ADHD). However, how common and rare genetic variants jointly contribute to individual liability requires further investigation in larger cohorts.

METHODS

This study comprises 9385 participants of European descent and 7810 participants of African American ancestry who were recruited from the greater Philadelphia area by the Children's Hospital of Philadelphia. The polygenic risk score (PRS) of each participant was estimated by linkage disequilibrium pruning and p-value thresholding (P + T) methods using PRSice-2. We investigated whether the risk of ADHD follows a polygenic liability threshold model wherein 1) the risk of ADHD requires less contribution from common variants in the presence of a rare CNV, and 2) control carriers of ADHD-associated CNVs have lower common risk allele burden than noncarriers.

RESULTS

CNVs previously reported in ADHD cases were significantly associated with ADHD risk in both the European American cohort and the African American cohort. Healthy control participants carrying those same risk CNVs had lower PRSs than those without risk CNVs in the European American cohort. This result was replicated in the African American cohort. However, PRSs were not significantly different in case participants carrying risk CNVs versus those without risk CNVs.

CONCLUSIONS

These findings provide evidence in support of interactive effects of PRS and ADHD-associated CNVs on disease risk and add novel insights into the genetic basis of ADHD by highlighting a protective role of low PRS in ADHD.

A Novel Intervention to Simultaneously Address the Dual Pathologies of Breathing Disorders During Sleep and Undiagnosed Attention Deficit Hyperactivity Disorder in School-Aged Children Ages 5-12

PURPOSE

To evaluate the improvement of ADHD related symptoms in school-aged children ages 5 to 12 in treatment with a monobloc appliance (MOA) for Sleep Disordered Breathing (SDB).

METHODS

A retrospective review of questionnaire scores of ADHD symptoms from school-aged children being treated with a MOA for SDB. Data was obtained from parent survey questionnaires of 40 school-aged children in three dental offices in treatment with an MOA for SDB showing symptoms of ADHD yet to be confirmed with a formal diagnosis between 2019 and 2021. ADHD symptom scores were ascertained by a parent survey questionnaire completed at the initial visit before MOA treatment, and 2 to 6 months, and 7+ months during MOA treatment.

RESULTS

At the 7+ month endpoint, 17 of the 28 (61%) children ages 5 to 12 saw at least a 1-point drop in the sum of their questionnaire scores indicating an improvement in ADHD symptoms after initiating treatment with an MOA. Although there was a reduction of the overall average symptom score from the initial visit to 2 to 6 months (M = 4.06, SD ± 1.55), a statistically significant improvement in ADHD symptoms occurred at the 7+ month endpoint (M = 15.29, SD ± 4.50) during MOA treatment.

CONCLUSIONS

Treatment with an MOA may be highly effective in addressing the dual pathologies of SDB and ADHD in school-age children ages 5 to 12.

Sleep disorders related to index and comorbid mental disorders and psychotropic drugs

PURPOSE

Mental disorders positively associate with sleep disorders. This study will explore the moderating influence of comorbid mental disorders and whether selected psychotropic drugs correlate with sleep disorders after adjusting for mental disorders.

METHODS

A retrospective cohort study design was employed using medical claim data from the Deseret Mutual Benefit Administrators (DMBA). Mental disorders, psychotropic drug use, and demographic data were extracted from claim files for ages 18-64, years 2016-2020.

RESULTS

Approximately 11.7% filed one or more claims for a sleep disorder [insomnia (2.2%) and sleep apnea (9.7%)]. Rates for selected mental disorders ranged from 0.09% for schizophrenia to 8.4% for anxiety. The rate of insomnia is greater in those with bipolar disorder or schizophrenia than in other mental disorders. The rate of sleep apnea is greater in those with bipolar disorder and depression. There is a significantly positive association between mental disorders and insomnia and sleep apnea, more so for insomnia, especially if they had other comorbid mental disorders. Psychotropic drugs other than CNS stimulants, primarily sedatives (non-barbiturate) and psychostimulants, explain much of the positive association between anxiety, depression, and bipolar disorder with insomnia. Psychotropic drugs with the largest effect on sleep disorders are sedatives (non-barbiturate) and psychostimulants for insomnia and psychostimulants and anticonvulsants for sleep apnea.

CONCLUSION

Mental disorders positively correlate with insomnia and sleep apnea. The positive association is greater when multiple mental illness exists. Bipolar disorder and schizophrenia are most strongly associated with insomnia, and bipolar disorder and depression are most strongly associated with sleep disorders. Psychotropic drugs other than CNS stimulants, primarily sedatives (non-barbiturate) and psychostimulants for treating anxiety, depression, or bipolar disorder are associated with higher levels of insomnia and sleep apnea.

An electronic health record (EHR) phenotype algorithm to identify patients with attention deficit hyperactivity disorders (ADHD) and psychiatric comorbidities

Background

In over half of pediatric cases, ADHD presents with comorbidities, and often, it is unclear whether the symptoms causing impairment are due to the comorbidity or the underlying ADHD. Comorbid conditions increase the likelihood for a more severe and persistent course and complicate treatment decisions. Therefore, it is highly important to establish an algorithm that identifies ADHD and comorbidities in order to improve research on ADHD using biorepository and other electronic record data.

Methods

It is feasible to accurately distinguish between ADHD in isolation from ADHD with comorbidities using an electronic algorithm designed to include other psychiatric disorders. We sought to develop an EHR phenotype algorithm to discriminate cases with ADHD in isolation from cases with ADHD with comorbidities more effectively for efficient future searches in large biorepositories. We developed a multi-source algorithm allowing for a more complete view of the patient’s EHR, leveraging the biobank of the Center for Applied Genomics (CAG) at Children’s Hospital of Philadelphia (CHOP). We mined EHRs from 2009 to 2016 using International Statistical Classification of Diseases and Related Health Problems (ICD) codes, medication history and keywords specific to ADHD, and comorbid psychiatric disorders to facilitate genotype-phenotype correlation efforts. Chart abstractions and behavioral surveys added evidence in support of the psychiatric diagnoses. Most notably, the algorithm did not exclude other psychiatric disorders, as is the case in many previous algorithms. Controls lacked psychiatric and other neurological disorders. Participants enrolled in various CAG studies at CHOP and completed a broad informed consent, including consent for prospective analyses of EHRs. We created and validated an EHR-based algorithm to classify ADHD and comorbid psychiatric status in a pediatric healthcare network to be used in future genetic analyses and discovery-based studies.

Results

In this retrospective case-control study that included data from 51,293 subjects, 5840 ADHD cases were discovered of which 46.1% had ADHD alone and 53.9% had ADHD with psychiatric comorbidities. Our primary study outcome was to examine whether the algorithm could identify and distinguish ADHD exclusive cases from ADHD comorbid cases. The results indicate ICD codes coupled with medication searches revealed the most cases. We discovered ADHD-related keywords did not increase yield. However, we found including ADHD-specific medications increased our number of cases by 21%. Positive predictive values (PPVs) were 95% for ADHD cases and 93% for controls.

Conclusion

We established a new algorithm and demonstrated the feasibility of the electronic algorithm approach to accurately diagnose ADHD and comorbid conditions, verifying the efficiency of our large biorepository for further genetic discovery-based analyses.

Trial registration

ClinicalTrials.gov, NCT02286817. First posted on 10 November 2014. ClinicalTrials.gov, NCT02777931. First posted on 19 May 2016. ClinicalTrials.gov, NCT03006367. First posted on 30 December 2016. ClinicalTrials.gov, NCT02895906. First posted on 12 September 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09447-9.

Current Pharmacological Treatments for ADHD

Attention-Deficit Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental condition associated with impaired function and increased risk of poor outcomes in children, young people and adults with the condition. Currently approved pharmacological treatments for ADHD include a range of stimulant (methylphenidate, amphetamine) and nonstimulant (atomoxetine, guanfacine, clonidine) medications. All have been shown to be effective in treating the symptoms of ADHD and improving other functional outcomes including quality of life, academic performance, rates of accidents and injuries, and do not appear to be associated with significant adverse outcomes or side effects. In this chapter, we review medications for ADHD by summarising the mechanisms of action of each of the two main classes of compounds (stimulants and nonstimulants), the formulations of the most commonly prescribed medications within each class, their efficacy in treating ADHD symptoms and other outcomes, and other factors that influence treatment decisions including side effects and tolerability, comorbidities and medical history. We conclude with a summary of the treatment decisions made by clinicians and suggest some next steps for research. Further research is needed to understand the mechanisms of action of these medications and how exactly they improve symptoms, and to examine their effects on commonly occurring comorbidities.

Metabolic Activation of Atomoxetine Mediated by Cytochrome P450 2D6

Atomoxetine (ATX) is a neurological drug widely used for the treatment of attention deficit-hyperactivity disorder. Liver injury has been documented in patients administered ATX. The mechanism of ATX's toxic action is less clear. This study is aimed to characterize reactive metabolites of ATX in vitro and in vivo to assist our understanding of the mechanisms of ATX hepatotoxicity. A hydroxylated metabolite, along with an O-dealkylation metabolite, was found in ATX-supplemented rat liver microsome incubations. Additionally, two glutathione (GSH) conjugates and two N-acetylcysteine (NAC) conjugates were observed in rat liver microsome incubations containing ATX, NADPH, and GSH or NAC. The corresponding GSH conjugates and NAC conjugates were found in bile and urine of ATX-treated rats, respectively. Recombinant P450 enzyme incubation study demonstrated that CYP2D6 dominated the metabolic activation of ATX. The insights gained from this study may be of assistance to illuminate the mechanisms of ATX-induced hepatotoxicity.

Neurotherapeutics for Attention Deficit/Hyperactivity Disorder (ADHD): A Review

This review focuses on the evidence for neurotherapeutics for attention deficit/hyperactivity disorder (ADHD). EEG-neurofeedback has been tested for about 45 years, with the latest meta-analyses of randomised controlled trials (RCT) showing small/medium effects compared to non-active controls only. Three small studies piloted neurofeedback of frontal activations in ADHD using functional magnetic resonance imaging or near-infrared spectroscopy, finding no superior effects over control conditions. Brain stimulation has been applied to ADHD using mostly repetitive transcranial magnetic and direct current stimulation (rTMS/tDCS). rTMS has shown mostly negative findings on improving cognition or symptoms. Meta-analyses of tDCS studies targeting mostly the dorsolateral prefrontal cortex show small effects on cognitive improvements with only two out of three studies showing clinical improvements. Trigeminal nerve stimulation has been shown to improve ADHD symptoms with medium effect in one RCT. Modern neurotherapeutics are attractive due to their relative safety and potential neuroplastic effects. However, they need to be thoroughly tested for clinical and cognitive efficacy across settings and beyond core symptoms and for their potential for individualised treatment.

Deep learning prediction of attention-deficit hyperactivity disorder in African Americans by copy number variation

Current understanding of the underlying molecular network and mechanism for attention-deficit hyperactivity disorder (ADHD) is lacking and incomplete. Previous studies suggest that genomic structural variations play an important role in the pathogenesis of ADHD. For effective modeling, deep learning approaches have become a method of choice, with ability to predict the impact of genetic variations involving complicated mechanisms. In this study, we examined copy number variation in whole genome sequencing from 116 African Americans ADHD children and 408 African American controls. We divided the human genome into 150 regions, and the variation intensity in each region was applied as feature vectors for deep learning modeling to classify ADHD patients. The accuracy of deep learning for predicting ADHD diagnosis is consistently around 78% in a two-fold shuffle test, compared with ∼50% by traditional k-mean clustering methods. Additional whole genome sequencing data from 351 European Americans children, including 89 ADHD cases and 262 controls, were applied as independent validation using feature vectors obtained from the African American ethnicity analysis. The accuracy of ADHD labeling was lower in this setting (∼70-75%) but still above the results from traditional methods. The regions with highest weight overlapped with the previously reported ADHD-associated copy number variation regions, including genes such as GRM1 and GRM8, key drivers of metabotropic glutamate receptor signaling. A notable discovery is that structural variations in non-coding genomic (intronic/intergenic) regions show prediction weights that can be as high as prediction weight from variations in coding regions, results that were unexpected.

Which came first: Cannabis use or deficits in impulse control?

Impulse control deficits are often found to co-occur with substance use disorders (SUDs). On the one hand, it is well known that chronic intake of drugs of abuse remodels the brain with significant consequences for a range of cognitive behaviors. On the other hand, individual variation in impulse control may contribute to differences in susceptibility to SUDs. Both of these relationships have been described, thus leading to a "chicken or the egg" debate which remains to be fully resolved. Does impulsivity precede drug use or does it manifest as a function of problematic drug usage? The link between impulsivity and SUDs has been most strongly established for cocaine and alcohol use disorders using both preclinical models and clinical data. Much less is known about the potential link between impulsivity and cannabis use disorder (CUD) or the directionality of this relationship. The initiation of cannabis use occurs most often during adolescence prior to the brain's maturation, which is recognized as a critical period of development. The long-term effects of chronic cannabis use on the brain and behavior have started to be explored. In this review we will summarize these observations, especially as they pertain to the relationship between impulsivity and CUD, from both a psychological and biological perspective. We will discuss impulsivity as a multi-dimensional construct and attempt to reconcile the results obtained across modalities. Finally, we will discuss possible avenues for future research with emerging longitudinal data.

Rare Recurrent Variants in Noncoding Regions Impact Attention-Deficit Hyperactivity Disorder (ADHD) Gene Networks in Children of both African American and European American Ancestry

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder with poorly understood molecular mechanisms that results in significant impairment in children. In this study, we sought to assess the role of rare recurrent variants in non-European populations and outside of coding regions. We generated whole genome sequence (WGS) data on 875 individuals, including 205 ADHD cases and 670 non-ADHD controls. The cases included 116 African Americans (AA) and 89 European Americans (EA), and the controls included 408 AA and 262 EA. Multiple novel rare recurrent variants were identified in exonic regions, functionally classified as stop-gains and frameshifts for known ADHD genes. Deletion in introns of the protocadherins families and the ncRNA HGB8P were identified in two independent EA ADHD patients. A meta-analysis of the two ethnicities for differential ADHD recurrent variants compared to controls shows a small number of overlaps. These results suggest that rare recurrent variants in noncoding regions may be involved in the pathogenesis of ADHD in children of both AA and EA ancestry; thus, WGS could be a powerful discovery tool for studying the molecular mechanisms of ADHD.

Methylphenidate for Mild Cognitive Impairment: An Exploratory 3-Day, Randomized, Double-Blind, Placebo-Controlled Trial

Background: To evaluate the efficacy, safety and tolerability of methylphenidate (MPH) for cognitive function in older patients with mild cognitive impairment (MCI).

Methods: Male and female subjects aged 65 years and older with a clinical diagnosis MCI were included in an exploratory randomized, double-blind, placebo-controlled trial. Eligible subjects were assigned to either treatment with immediate-release MPH or placebo. The active compound was administered in an increasing-dose stepwise fashion, namely 10 mg MPH on day 1, 20 mg on day 2, and 30 mg on day 3. Subjects remained under observation for 4 h following drug administration and were monitored for changes in blood pressure and for adverse events. Cognitive outcome measures included the Montreal Cognitive Assessment (MoCA) and the Neurotrax Mindstreams computerized cognitive assessment battery.

Results: Of 17 subjects enrolled, 15 subjects completed the study, 7 in the active MPH group and 8 in the placebo group. The average age of the participants was 76.1 ± 6.6 years and 10 (66.7%) were men. Following the final dose a significant benefit on memory (predominantly non-verbal memory) was found in the MPH group. While 12 adverse events were reported, they were all rated as mild to moderate.

Conclusions: Our finding of modest beneficial effects of MPH on memory tests in older subjects with MCI in this exploratory study is of interest and should be investigated in further studies.

Amphetamine Use in the Elderly: A Systematic Review of the Literature

Objective:

To systematically review the literature on the therapeutic use of amphetamine, lisdexamfetamine and methylphenidate in elderly population with and without dementia.

Methods:

We conducted two researches on the PubMed, Scopus and Embase using the keywords (“elderly”) AND (“amphetamine” OR “methylphenidate” OR “lisdexamfetamine”) and then (“Alzheimer” OR “dementia”) AND (“amphetamine” OR “methylphenidate” OR “lisdexamfetamine”).

Results:

Twenty-nine papers met all the eligibility criteria. The results are encouraging as 81.5% of the studies showed clinical improvement of the investigated condition.

Conclusion:

Amphetamines and methylphenidate are probably effective strategies for different conditions in the elderly population. However, further studies are needed to provide more robust evidence on efficacy, dosage and safety for this population.

Mitochondrial DNA haplogroups and risk of attention deficit and hyperactivity disorder in European Americans

Although mitochondrial dysfunction has been implicated in the pathophysiology of attention deficit and hyperactivity disorder ADHD, the role of mitochondrial DNA (mtDNA) has not been extensively investigated. To determine whether mtDNA haplogroups influence risk of ADHD, we performed a case-control study comprising 2076 ADHD cases and 5078 healthy controls, all of whom were European decedents recruited from The Children's Hospital of Philadelphia (CHOP). Associations between eight major European mtDNA Haplogroups and ADHD risk were assessed in three independent European cohorts. Meta-analysis of the three studies indicated that mtDNA haplogroups K (odds ratio = 0.69, P = 2.24 × 10^-4, P_corrected = 1.79 × 10^-3) and U (odds ratio = 0.77, P = 8.88 × 10^-4, P_corrected = 7.11 × 10^-3) were significantly associated with reduced risk of ADHD. In contrast, haplogroup HHV* (odds ratio = 1.18, P = 2.32 × 10^-3, P_corrected = 0.019) was significantly associated with increased risk of ADHD. Our results provide novel insight into the genetic basis of ADHD, implicating mitochondrial mechanisms in the pathophysiology of this relatively common psychiatric disorder.

Non-coding structural variation differentially impacts attention-deficit hyperactivity disorder (ADHD) gene networks in African American vs Caucasian children

Previous studies of attention-deficit hyperactivity disorder (ADHD) have suggested that structural variants (SVs) play an important role but these were mainly studied in subjects of European ancestry and focused on coding regions. In this study, we sought to address the role of SVs in non-European populations and outside of coding regions. To that end, we generated whole genome sequence (WGS) data on 875 individuals, including 205 ADHD cases and 670 non-ADHD controls. The ADHD cases included 116 African Americans (AA) and 89 of European Ancestry (EA) with SVs in comparison with 408 AA and 262 controls, respectively. Multiple SVs and target genes that associated with ADHD from previous studies were identified or replicated, and novel recurrent ADHD-associated SV loci were discovered. We identified clustering of non-coding SVs around neuroactive ligand-receptor interaction pathways, which are involved in neuronal brain function, and highly relevant to ADHD pathogenesis and regulation of gene expression related to specific ADHD phenotypes. There was little overlap (around 6%) in the genes impacted by SVs between AA and EA. These results suggest that SVs within non-coding regions may play an important role in ADHD development and that WGS could be a powerful discovery tool for studying the molecular mechanisms of ADHD

The Effects of Methylphenidate Treatment on Child Growth in Thai Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

Objectives: To determine the effects of methylphenidate treatment on child growth in Thai pediatric patients with attention-deficit/hyperactivity disorder (ADHD). Methods: The medical records of children and adolescents with ADHD, between 5 and 18 years of age, who received pharmacological treatment with methylphenidate as a sole psychiatric medication for ≥1 year between 2001 and 2018 at the Rajanagarindra Institute of Child Development, Thailand, were retrospectively reviewed. Data on anthropometric parameters and methylphenidate use were extracted. Height and weight were converted to age- and gender-corrected standard scores (z-scores) using norms from the Thai pediatric population. Changes in height and weight z-scores were assessed using a paired t-test or one-way repeated measures ANOVA with the Bonferroni correction. Results: In this retrospective observational study, 911 children and adolescents were eligible, with the mean age of 95.0 ± 19.5 months at baseline, the cumulative duration of methylphenidate treatment of 39.4 ± 23.5 months, and the average daily dosage of 14.1 ± 6.2 mg/day. Comparative analysis found no statistically significant change in height z-scores between baseline and last recorded measurement (mean difference = 0.0017, confidence interval [95% CI] = -0.0004 to 0.0038, p = 0.107), while a slight, but significant increase in weight z-scores was observed (mean difference = 0.0271, 95% CI = 0.0179-0.0362, p < 0.001). Longitudinal analysis observed that weight z-scores were significantly decreased during the first year of therapy, but regained in the second year and continued to increase in subsequent years of therapy. Conclusion: Treatment with methylphenidate in our cohort of Thai pediatric patients with ADHD was not associated with growth deficits, except for a slightly significant decrease in weight during the first year of therapy.

Effects of neurofeedback versus methylphenidate for the treatment of attention-deficit/hyperactivity disorder protocol for a systematic review and meta-analysis of head-to-head trials

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is developmental disorder characterized by inattention and/or hyperactivity/impulsivity. Psychostimulants, including methylphenidate (MPH), are recommended as a first-line pharmacological intervention, whereas neurofeedback (NF) has been proposed as a nonpharmacological option. The comparative effects of MPH and NF need further exploration. We will conduct a systematic review and meta-analysis of head-to-head randomized controlled trials (RCTs) comparing the efficacy and/or tolerability of MPH and NF in children/adolescents and adults with ADHD.

METHOD AND ANALYSIS

We will include published as well as unpublished data. Two investigators will independently search PubMed, OVID, ERIC, Web of Science, ClinialTrials.gov, and a set of Chinese databases, including CNKI, CQVIP, and WanFang for head-to-head RCTs comparing MPH and NF. Experts will be contacted for unpublished data. The primary outcome will be the efficacy on ADHD core symptoms, measured by the change in the severity of ADHD symptoms, from baseline to endpoint and, if available, at follow-up (at any available time point). Secondary outcomes will be: dropouts for any reasons; efficacy on neuropsychological measures (working memory, inattention, and inhibition). We will conduct subgroup analyses to assess the impact of the following variables: age; type of NF; language of publication; comorbidities. Additionally, we will carry out meta-regression analyses to investigate the effect of sponsorship, year of publication, duration of intervention, and age of participants. Sensitivity analyses will be conducted to test the robustness of the findings. Risk of bias of individual studies will be assessed using the Cochrane risk of bias tool. Analyses will be performed using Comprehensive Meta-Analysis Software.

ETHICS AND DISSEMINATION

No ethical issues are foreseen. Results from this study will be published in a peer-reviewed journal and presented at relevant national and international conferences.

TRIALS REGISTRATION NUMBER

PROSPERO CRD42018090256.

Next-generation sequencing in drug development: target identification and genetically stratified clinical trials

Next-generation sequencing (NGS) enabled high-throughput analysis of genotype-phenotype relationships on human populations, ushering in a new era of genetics-informed drug development. The year 2017 was remarkable, with the first FDA-approved gene therapy for cancer (Kymriah™) and for inherited diseases (LUXTURNA™), the first multiplex NGS panel for companion diagnostics (MSK-IMPACT™) and the first drug targeting a genetic signature rather than a disease (Keytruda^®). We envision that population-scale NGS with paired electronic health records (EHRs) will become a routine measure in the drug development process for the identification of novel drug targets, and that genetically stratified clinical trials could be widely adopted to improve power in precision-medicine-guided drug development.

Pharmacokinetics of a New Amphetamine Extended-Release Oral Suspension in Children with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

An extended-release amphetamine (AMP) oral suspension has been developed to facilitate medication ingestion and dose titration. This study sought to determine the pharmacokinetic (PK) profile of this new formulation in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

This was an open-label, single-period, PK study in 29 pediatric participants with ADHD. Participants were stratified into age groups 1 (6-7 years), 2 (8-9 years), and 3 (10-12 years), and dosed with 15 mL extended-release AMP liquid suspension (equivalent to 30 mg mixed AMP salts) after an overnight fast. Blood samples were collected at prespecified time points and analyzed for d- and l-AMP concentrations. Key PK parameters included maximum plasma concentration (C_max), time to maximum plasma concentration, half-life (T_1/2), area under the curve from time 0 to last quantifiable concentration (AUC_last) and to infinity (AUC_inf), oral clearance (CL/F), and volume of distribution (Vz/F). The 95% confidence intervals (CIs) about the geometric means of the weight-normalized CL/F, Vz/F, and AUC_last were determined. Safety was also assessed.

RESULTS

All participants completed the study. As age increased, mean maximum and total exposure to AMP decreased; weight-normalized CL/F slightly increased, resulting in decreasing T_1/2 values with age. For d- and l-AMP, the 95% CIs for the geometric means of weight-normalized CL/F/kg and Vz/F/kg were within the 60%-140% range for groups 2 and 3, while those of weight-normalized AUC_last were within range for all age groups. Adverse events were mild and consistent with the safety profile of AMP.

CONCLUSIONS

Exposure (C_max, AUC_inf, and AUC_last) to AMP decreased with age, possibly as a result of the 30-mg/15-mL fixed dose across a range of weights (20-57 kg) and the consequent lower dose per kilogram in older participants, as well as the slight increase in clearance with age.

Fasoracetam in adolescents with ADHD and glutamatergic gene network variants disrupting mGluR neurotransmitter signaling

The glutamatergic neurotransmitter system may play an important role in attention-deficit hyperactivity disorder (ADHD). This 5-week, open-label, single-blind, placebo-controlled study reports the safety, pharmacokinetics and responsiveness of the metabotropic glutamate receptor (mGluR) activator fasoracetam (NFC-1), in 30 adolescents, age 12-17 years with ADHD, harboring mutations in mGluR network genes. Mutation status was double-blinded. A single-dose pharmacokinetic profiling from 50-800 mg was followed by a single-blind placebo at week 1 and subsequent symptom-driven dose advancement up to 400 mg BID for 4 weeks. NFC-1 treatment resulted in significant improvement. Mean Clinical Global Impressions-Improvement (CGI-I) and Severity (CGI-S) scores were, respectively, 3.79 at baseline vs. 2.33 at week 5 (P < 0.001) and 4.83 at baseline vs. 3.86 at week 5 (P < 0.001). Parental Vanderbilt scores showed significant improvement for subjects with mGluR Tier 1 variants (P < 0.035). There were no differences in the incidence of adverse events between placebo week and weeks on active drug. The trial is registered at https://clinicaltrials.gov/ct2/show/study/NCT02286817 .

The safety of extended-release drug formulations for the treatment of ADHD

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is a complex neurobehavioral disorder affecting millions of patients worldwide. Effective treatments have been available for more than 60 years in the form of immediate-release (IR) stimulants However, stimulants have a high risk for abuse and are associated with adverse effects Including elevated blood pressure and heart rate, insomnia and decreased appetite. IR formulations also require multiple daily dosing. The search for improved safety, tolerability and convenience has led to the development of multiple extended-release (ER) stimulant and non-stimulant formulations. Areas covered: Adverse effects of (ER) products including amphetamine, methylphenidate, clonidine and guanfacine will be reviewed and their significance discussed. Expert opinion: Limitations of currently marketed medications have led to the search for drugs with efficacy comparable to ER stimulants and a more favorable adverse event profile. Several are in development, but their potential utility is not yet known. Current research is also focused on finding specific genetic defects in patients with ADHD. Exciting progress has been made with the identification of mGluR receptor defects in some patients. However because of the heterogeneity of the disorder, effective targeted treatments for the majority of patients with ADHD does not appear likely in the near future.

The use of modified-release methylphenidate in the treatment of attention-deficit/hyperactivity disorder

INTRODUCTION

Since Ritalin® (Methylphenidate-Immediate release or MPH-IR) was introduced for the treatment of attention-deficit/hyperactivity disorder, multiple formulations of MPH have been developed. The specific formulation determines the pharmacokinetic (PK) profile and the onset and duration of action for the compound. Areas covered: Aptensio XR® is a multilayer-release MPH (MPH-MLR) consisting of an MPH-IR layer (40%) and an extended-release (ER) portion of 60% of MPH. It has an initial maximum MPH concentration at about two hours (h) and a second concentration peak at approximately 8 h. This formulation allows for a rapid onset of effect by 1 h and a duration of action through 12 h after dosing. The chemistry, PK, efficacy and adverse event profile of MPH-MLR will be reviewed. Expert commentary: Although the PK profile may prove beneficial to patients in the late afternoon and early evening, it is not clear if this is a significant advantage compared with other MPH-ER formulations.

Effectiveness of Parent-Child Interaction Therapy (PCIT) in the Treatment of Young Children's Behavior Problems. A Randomized Controlled Study

OBJECTIVE

The aim of the present investigation was to compare the effectiveness of Parent-Child Interaction Therapy (PCIT) with treatment as usual (TAU) in young children who were referred to regular child and adolescent mental health clinics for behavior problems.

METHOD

Eighty-one Norwegian families with two- to seven-year-old children (52 boys) who had scored ≥ 120 on the Eyberg Child Behavior Inventory (ECBI) were randomly assigned to receive either PCIT or TAU. The families were assessed 6 and 18 months after beginning treatment. Parenting skills were measured using the Dyadic Parent-Child Interaction Coding System (DPICS), and child behavior problems were measured using the ECBI and the Child Behavior Checklist (CBCL).

RESULTS

Linear growth curve analyses revealed that the behavior problems of children receiving PCIT improved more compared with children receiving TAU according to mother reports (ECBI d = .64, CBCL d = .61, both p < .05) but not according to father report. Parents also improved with regard to Do and Don't skills (d = 2.58, d = 1.46, respectively, both p ≤ .001). At the 6-month assessment, which often occurred before treatment was finished, children who had received PCIT had lower father-rated ECBI and mother-rated CBCL-scores (p = .06) compared with those who had received TAU. At the 18-month follow-up, the children who had received PCIT showed fewer behavior problems compared with TAU according to mother (d = .37) and father (d = .56) reports on the ECBI and mother reports on the CBCL regarding externalizing problems (d = .39). Parents receiving PCIT developed more favorable Do Skills (6-month d = 1.81; 18-month d = 1.91) and Don't Skills (6-month d = 1.46; 18-month d = 1.42) according to observer ratings on the DPICS compared with those receiving TAU.

CONCLUSION

Children receiving PCIT in regular clinical practice exhibited a greater reduction in behavior problems compared with children receiving TAU, and their parents' parenting skills improved to a greater degree compared with those receiving TAU.

TRIAL REGISTRATION

ClinicalTrials.gov NTC01085305.