Guanfacine Extended Release: A New Pharmacological Treatment Option in Europe

Alzheimer's disease approaches - Focusing on pathology, biomarkers and clinical trial candidates

The strategy for the development of new drugs for Alzheimer's disease (AD) recognizes that an effective therapy requires early therapeutic intervention and a multifactorial approach that considers the individual initiators of AD development. Current knowledge of AD includes the understanding of pathophysiology, risk factors, biomarkers, and the evolving patterns of biomarker abnormalities. This knowledge is essential in identifying potential molecular targets for new drug development. This review summarizes promising AD drug candidates, many of which are currently in phase 2 or 3 clinical trials. New agents are classified according to the Common Alzheimer's Disease Research Ontology (CADRO). The main targets of new drugs for AD are processes related to amyloid beta and tau neurotoxicity, neurotransmission, inflammation, metabolism and bioenergetics, synaptic plasticity, and oxidative stress. These interventions are aimed at preventing disease onset and slowing or eliminating disease progression. The efficacy of pharmacotherapy may be enhanced by combining these drugs with other treatments, antioxidants, and dietary supplements. Ongoing research into AD pathophysiology, risk factors, biomarkers, and the dynamics of biomarker abnormalities may contribute to the understanding of AD and offer hope for effective therapeutic strategies in the near future.

Withdrawal Dyskinesia Associated With Aripiprazole in a Child: A Case Report

Atypical antipsychotics are considered to be better tolerated than typical antipsychotics; however, the risk of drug-induced movement disorders needs to be considered. Aripiprazole, a dopamine partial agonist, is one of the most frequently used atypical antipsychotics in children. In this report, we describe withdrawal dyskinesia after aripiprazole discontinuation in a child with autism spectrum disorder. The patient presented with oral dyskinesia after discontinuation of aripiprazole when he was 13 years old. Dyskinetic movements disappeared after reinitiation of aripiprazole. He developed oral dyskinesia again after a reduction of the aripiprazole dose when he was 14 years old. Dyskinesia gradually disappeared within a few months. Withdrawal dyskinesia associated with aripiprazole has been rarely reported in children. Moreover, there is no large study on the prevalence of dyskinesia associated with aripiprazole discontinuation either in adults or in children. However, relevant cases might be unreported, pretermitted, or regarded as akathisia or symptoms of attention-deficit hyperactivity disorder. The prevalence of withdrawal dyskinesia associated with aripiprazole, especially in children, may be more frequent than thought. Withdrawal dyskinesia is self-limited; however, such dyskinetic movements in children potentially result in irreversible effects that damage the quality of life. As such, physicians should be mindful when changing, reducing, or discontinuing antipsychotics in children.

Methylphenidate alleviates cognitive dysfunction caused by early manganese exposure: Role of catecholaminergic receptors

Environmental manganese (Mn) exposure is associated with impaired attention and psychomotor functioning, as well as impulsivity/hyperactivity in children and adolescents. We have shown previously that developmental Mn exposure can cause these same dysfunctions in a rat model. Methylphenidate (MPH) lessens impairments in attention, impulse control, and psychomotor function in children, but it is unknown whether MPH ameliorates these dysfunctions when induced by developmental Mn exposure. Here, we sought to (1) determine whether oral MPH treatment ameliorates the lasting attention and sensorimotor impairments caused by developmental Mn exposure, and (2) elucidate the mechanism(s) of Mn neurotoxicity and MPH effectiveness. Rats were given 50 mg Mn/kg/d orally over PND 1-21 and assessed as adults in a series of attention, impulse control and sensorimotor tasks during oral MPH treatment (0, 0.5, 1.5, or 3.0 mg/kg/d). Subsequently, selective catecholaminergic receptor antagonists were administered to gain insight into the mechanism(s) of action of Mn and MPH. Developmental Mn exposure caused persistent attention and sensorimotor impairments. MPH treatment at 0.5 mg/kg/d completely ameliorated the Mn attentional dysfunction, whereas the sensorimotor deficits were ameliorated by the 3.0 mg/kg/d MPH dose. Notably, the MPH benefit on attention was only apparent after prolonged treatment, while MPH efficacy for the sensorimotor deficits emerged early in treatment. Selectively antagonizing D1, D2, or α2A receptors had no effect on the Mn-induced attentional dysfunction or MPH efficacy in this domain. However, antagonism of D2R attenuated the Mn sensorimotor deficits, whereas the efficacy of MPH to ameliorate those deficits was diminished by D1R antagonism. These findings demonstrate that MPH is effective in alleviating the lasting attentional and sensorimotor dysfunction caused by developmental Mn exposure, and they clarify the mechanisms underlying developmental Mn neurotoxicity and MPH efficacy. Given that the cause of attention and psychomotor deficits in children is often unknown, these findings have implications for the treatment of environmentally induced attentional and psychomotor dysfunction in children more broadly.

Combined Use of Guanfacine and N-Acetylcysteine for the Treatment of Cognitive Deficits After Traumatic Brain Injury

Traumatic Brain Injury (TBI) is a significant contributor to disability across the world. TBIs vary in severity, and most cases are designated mild TBI (mTBI), involving only brief loss of consciousness and no intracranial findings on imaging. Despite this categorization, many persons continue to report persistent cognitive changes in the months to years after injury, with particular impairment in the cognitive and executive functions of the pre-frontal cortex. For these persons, there are no currently approved medications, and treatment is limited to symptom management and cognitive or behavioral therapy. The current case studies explored the use of the alpha-2A adrenoreceptor agonist, guanfacine, combined with the antioxidant, N-acetylcysteine (NAC), in the treatment of post-TBI cognitive symptoms, based on guanfacine's ability to strengthen pre-frontal cortical function, and the open-label use of NAC in treating TBI. Two persons from our TBI clinic were treated with this combined regimen, with neuropsychological testing performed pre- and post-treatment. Guanfacine + NAC improved attention, processing speed, memory, and executive functioning with minimal side effects in both persons. These results encourage future placebo-controlled trials to more firmly establish the efficacy of guanfacine and NAC for the treatment of cognitive deficits caused by TBI.

Serotonergic and Adrenergic Neuroreceptor Manipulation Ameliorates Core Symptoms of ADHD through Modulating Dopaminergic Receptors in Spontaneously Hypertensive Rats

The core symptoms of attention deficit hyperactivity disorder (ADHD) are due to the hypofunction of the brain's adrenergic (NE) and dopamine (DA) systems. Drugs that enhance DA and NE neurotransmission in the brain by blocking their transporters or receptors are the current therapeutic strategies. Of late, the emerging results point out the serotonergic (5-HT) system, which indirectly modulates the DA activity in reducing the core symptoms of ADHD. On this basis, second-generation antipsychotics, which utilize 5-HT receptors, were prescribed to children with ADHD. However, it is not clear how serotonergic receptors modulate the DA activity to minimize the symptoms of ADHD. The present study investigates the efficacy of serotonergic and alpha-2 adrenergic receptor manipulation in tackling the core symptoms of ADHD and how it affects the DA neuroreceptors in the brain regions involved in ADHD. Fifteen-day-old male spontaneously hypertensive rats (SHRs) received 5-HT1A agonist (ipsapirone) or 5-HT2A antagonist (MDL 100907) (i.p.) or alpha-2 agonist (GFC) from postnatal days 15 to 42 along with age-matched Wistar Kyoto rats (WKY) (n = 8 in each group). ADHD-like behaviors were assessed using a battery of behavioral tests during postnatal days 44 to 65. After the behavioral tests, rat brains were processed to estimate the density of 5-HT1A, 5-HT2A, DA-D1, and DA-D2 neuroreceptors in the prefrontal cortex, the striatum, and the substantia nigra. All three neuroreceptor manipulations were able to minimize the core symptoms of ADHD in SHRs. The positive effect was mainly associated with the upregulation of 5-HT2A receptors in all three areas investigated, while 5-HT1A was in the prefrontal cortex and the substantia nigra. Further, the DA-D1 receptor expression was downregulated by all three neuroreceptor manipulations except for alpha-2 adrenergic receptor agonists in the striatum and 5-HT2A antagonists in the substantia nigra. The DA-D2 expression was upregulated in the striatum while downregulated in the prefrontal cortex and the substantia nigra. In this animal model study, the 5-HT1A agonist or 5-HT2A antagonist monotherapies were able to curtail the ADHD symptoms by differential expression of DA receptors in different regions of the brain.

Pharmacological intervention for irritability, aggression, and self-injury in autism spectrum disorder (ASD)

BACKGROUND

Pharmacological interventions are frequently used for people with autism spectrum disorder (ASD) to manage behaviours of concern, including irritability, aggression, and self-injury. Some pharmacological interventions might help treat some behaviours of concern, but can also have adverse effects (AEs).

OBJECTIVES

To assess the effectiveness and AEs of pharmacological interventions for managing the behaviours of irritability, aggression, and self-injury in ASD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, 11 other databases and two trials registers up to June 2022. We also searched reference lists of relevant studies, and contacted study authors, experts and pharmaceutical companies.

SELECTION CRITERIA

We included randomised controlled trials of participants of any age with a clinical diagnosis of ASD, that compared any pharmacological intervention to an alternative drug, standard care, placebo, or wait-list control.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were behaviours of concern in ASD, (irritability, aggression and self-injury); and AEs. Secondary outcomes were quality of life, and tolerability and acceptability. Two review authors independently assessed each study for risk of bias, and used GRADE to judge the certainty of the evidence for each outcome.

MAIN RESULTS

We included 131 studies involving 7014 participants in this review. We identified 26 studies as awaiting classification and 25 as ongoing. Most studies involved children (53 studies involved only children under 13 years), children and adolescents (37 studies), adolescents only (2 studies) children and adults (16 studies), or adults only (23 studies). All included studies compared a pharmacological intervention to a placebo or to another pharmacological intervention. Atypical antipsychotics versus placebo At short-term follow-up (up to 6 months), atypical antipsychotics probably reduce irritability compared to placebo (standardised mean difference (SMD) -0.90, 95% confidence interval (CI) -1.25 to -0.55, 12 studies, 973 participants; moderate-certainty evidence), which may indicate a large effect. However, there was no clear evidence of a difference in aggression between groups (SMD -0.44, 95% CI -0.89 to 0.01; 1 study, 77 participants; very low-certainty evidence). Atypical antipsychotics may also reduce self-injury (SMD -1.43, 95% CI -2.24 to -0.61; 1 study, 30 participants; low-certainty evidence), possibly indicating a large effect. There may be higher rates of neurological AEs (dizziness, fatigue, sedation, somnolence, and tremor) in the intervention group (low-certainty evidence), but there was no clear evidence of an effect on other neurological AEs. Increased appetite may be higher in the intervention group (low-certainty evidence), but we found no clear evidence of an effect on other metabolic AEs. There was no clear evidence of differences between groups in musculoskeletal or psychological AEs. Neurohormones versus placebo At short-term follow-up, neurohormones may have minimal to no clear effect on irritability when compared to placebo (SMD -0.18, 95% CI -0.37 to -0.00; 8 studies; 466 participants; very low-certainty evidence), although the evidence is very uncertain. No data were reported for aggression or self -injury. Neurohormones may reduce the risk of headaches slightly in the intervention group, although the evidence is very uncertain. There was no clear evidence of an effect of neurohormones on any other neurological AEs, nor on any psychological, metabolic, or musculoskeletal AEs (low- and very low-certainty evidence). Attention-deficit hyperactivity disorder (ADHD)-related medications versus placebo At short-term follow-up, ADHD-related medications may reduce irritability slightly (SMD -0.20, 95% CI -0.40 to -0.01; 10 studies, 400 participants; low-certainty evidence), which may indicate a small effect. However, there was no clear evidence that ADHD-related medications have an effect on self-injury (SMD -0.62, 95% CI -1.63 to 0.39; 1 study, 16 participants; very low-certainty evidence). No data were reported for aggression. Rates of neurological AEs (drowsiness, emotional AEs, fatigue, headache, insomnia, and irritability), metabolic AEs (decreased appetite) and psychological AEs (depression) may be higher in the intervention group, although the evidence is very uncertain (very low-certainty evidence). There was no evidence of a difference between groups for any other metabolic, neurological, or psychological AEs (very low-certainty evidence). No data were reported for musculoskeletal AEs. Antidepressants versus placebo At short-term follow-up, there was no clear evidence that antidepressants have an effect on irritability (SMD -0.06, 95% CI -0.30 to 0.18; 3 studies, 267 participants; low-certainty evidence). No data for aggression or self-injury were reported or could be included in the analysis. Rates of metabolic AEs (decreased energy) may be higher in participants receiving antidepressants (very low-certainty evidence), although no other metabolic AEs showed clear evidence of a difference. Rates of neurological AEs (decreased attention) and psychological AEs (impulsive behaviour and stereotypy) may also be higher in the intervention group (very low-certainty evidence) although the evidence is very uncertain. There was no clear evidence of any difference in the other metabolic, neurological, or psychological AEs (very low-certainty evidence), nor between groups in musculoskeletal AEs (very low-certainty evidence). Risk of bias We rated most of the studies across the four comparisons at unclear overall risk of bias due to having multiple domains rated as unclear, very few rated as low across all domains, and most having at least one domain rated as high risk of bias.

AUTHORS' CONCLUSIONS

Evidence suggests that atypical antipsychotics probably reduce irritability, ADHD-related medications may reduce irritability slightly, and neurohormones may have little to no effect on irritability in the short term in people with ASD. There was some evidence that atypical antipsychotics may reduce self-injury in the short term, although the evidence is uncertain. There was no clear evidence that antidepressants had an effect on irritability. There was also little to no difference in aggression between atypical antipsychotics and placebo, or self-injury between ADHD-related medications and placebo. However, there was some evidence that atypical antipsychotics may result in a large reduction in self-injury, although the evidence is uncertain. No data were reported (or could be used) for self-injury or aggression for neurohormones versus placebo. Studies reported a wide range of potential AEs. Atypical antipsychotics and ADHD-related medications in particular were associated with an increased risk of metabolic and neurological AEs, although the evidence is uncertain for atypical antipsychotics and very uncertain for ADHD-related medications. The other drug classes had minimal or no associated AEs.

Methylphenidate alleviates cognitive dysfunction from early Mn exposure: Role of catecholaminergic receptors

Environmental manganese (Mn) exposure is associated with impaired attention and psychomotor functioning, as well as impulsivity/hyperactivity in children and adolescents. We have shown previously that developmental Mn exposure can cause these same dysfunctions in a rat model. Methylphenidate (MPH) lessens impairments in attention, impulse control, and sensorimotor function in children, but it is unknown whether MPH ameliorates these dysfunctions when induced by developmental Mn exposure. Here, we sought to (1) determine whether oral MPH treatment ameliorates the lasting attention and sensorimotor impairments caused by developmental Mn exposure, and (2) elucidate the mechanism(s) of Mn neurotoxicity and MPH effectiveness. Rats were given 50 mg Mn/kg/d orally over PND 1-21 and assessed as adults in a series of attention, impulse control and sensorimotor tasks during oral MPH treatment (0, 0.5, 1.5, or 3.0 mg/kg/d). Subsequently, selective catecholaminergic receptor antagonists were administered to gain insight into the mechanism(s) of action of Mn and MPH. Developmental Mn exposure caused persistent attention and sensorimotor impairments. MPH treatment at 0.5 mg/kg/d completely ameliorated the Mn attentional dysfunction, whereas the sensorimotor deficits were ameliorated by the 3.0 mg/kg/d MPH dose. Notably, the MPH benefit on attention was only apparent after prolonged treatment, while MPH efficacy for the sensorimotor deficits emerged early in treatment. Selectively antagonizing D1, D2, or α2A receptors had no effect on the Mn-induced attentional dysfunction or MPH efficacy in this domain. However, antagonism of D2R attenuated the Mn sensorimotor deficits, whereas the efficacy of MPH to ameliorate those deficits was diminished by D1R antagonism. These findings demonstrate that MPH is effective in alleviating the lasting attention and sensorimotor dysfunction caused by developmental Mn exposure, and they clarify the mechanisms underlying developmental Mn neurotoxicity and MPH efficacy. Given that the cause of attention and psychomotor deficits in children is often unknown, these findings have implications for the treatment of environmentally-induced attentional and psychomotor dysfunction in children more broadly.

The association between type 2 diabetes and attention- deficit/hyperactivity disorder: A systematic review, meta-analysis, and population-based sibling study

We conducted a systematic review and a meta-analysis to quantitatively summarize evidence on the association between attention-deficit/hyperactivity disorder (ADHD) and type 2 diabetes (T2D). Moreover, a register-based sibling study was conducted to simultaneously control for confounding factors. A systematic search identified four eligible observational studies (N = 5738,287). The meta-analysis showed that individuals with ADHD have a more than doubled risk of T2D when considering adjusted estimates (OR=2.29 [1.48-3.55], d=0.46). Results from the register-based Swedish data showed a significant association between ADHD and T2D (HR=2.35 [2.14-2.58]), with substance use disorder, depression, and anxiety being the main drivers of the association, and cardiovascular and familiar risk playing a smaller role. While results from the meta-analysis provide evidence for an increased risk of T2D in individuals with ADHD, the register-based analyses show that the association between ADHD and T2D is largely explained by psychiatric comorbidities. Pending further evidence of causal association, our findings suggest that early identification and treatment of ADHD comorbidities might greatly reduce the risk of developing T2D in individuals with ADHD.

Noradrenergic Modulation of Learned and Innate Behaviors in Dopamine Transporter Knockout Rats by Guanfacine

Investigation of the precise mechanisms of attention deficit and hyperactivity disorder (ADHD) and other dopamine-associated conditions is crucial for the development of new treatment approaches. In this study, we assessed the effects of repeated and acute administration of α2A-adrenoceptor agonist guanfacine on innate and learned forms of behavior of dopamine transporter knockout (DAT-KO) rats to evaluate the possible noradrenergic modulation of behavioral deficits. DAT-KO and wild type rats were trained in the Hebb-Williams maze to perform spatial working memory tasks. Innate behavior was evaluated via pre pulse inhibition (PPI). Brain activity of the prefrontal cortex and the striatum was assessed. Repeated administration of GF improved the spatial working memory task fulfillment and PPI in DAT-KO rats, and led to specific changes in the power spectra and coherence of brain activity. Our data indicate that both repeated and acute treatment with a non-stimulant noradrenergic drug lead to improvements in the behavior of DAT-KO rats. This study further supports the role of the intricate balance of norepinephrine and dopamine in the regulation of attention. The observed compensatory effect of guanfacine on the behavior of hyperdopaminergic rats may be used in the development of combined treatments to support the dopamine-norepinephrine balance.

An overview on neurobiology and therapeutics of attention-deficit/hyperactivity disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent psychiatric condition characterized by developmentally inappropriate symptoms of inattention and/or hyperactivity/impulsivity, which leads to impairments in the social, academic, and professional contexts. ADHD diagnosis relies solely on clinical assessment based on symptom evaluation and is sometimes challenging due to the substantial heterogeneity of the disorder in terms of clinical and pathophysiological aspects. Despite the difficulties imposed by the high complexity of ADHD etiology, the growing body of research and technological advances provide good perspectives for understanding the neurobiology of the disorder. Such knowledge is essential to refining diagnosis and identifying new therapeutic options to optimize treatment outcomes and associated impairments, leading to improvements in all domains of patient care. This review is intended to be an updated outline that addresses the etiological and neurobiological aspects of ADHD and its treatment, considering the impact of the "omics" era on disentangling the multifactorial architecture of ADHD.

Addressing Emotional Dysregulation and Potential Pharmacogenetic Implication of 5-HTTLPR Genotype in Attention Deficit Hyperactivity Disorder

Background

This review unpacks the emotional presentation of externalizing behaviors in attention deficit hyperactivity disorder (ADHD), by diving into the psychophysiology, neurophysiology, and neurogenetics in relation to executive function. The correlations among these three variables are identified, showing that standard assessments for ADHD leave out the emotional dysregulation element. This may lead to suboptimal management outcomes during the developmental progression into adolescence and adulthood.

Summary

The emotional impulsivity manifestation in adolescence and adulthood related to the under-managed emotional dysregulation in childhood is found to be associated with subtle confounding impact of 5-HTTLPR (serotonin-transporter-linked promoter region) genotype. The genotype of interest affects the neurochemistry, neurophysiology, and psychophysiology of the cognition for executive function. The established practice of using methylphenidate in treating ADHD surprisingly has a neurogenetic effect in targeting the genotype of interest. Methylphenidate provides neuroprotective effects throughout the neurodevelopment timeline from childhood to adulthood.

Key Messages

The emotional dysregulation element in ADHD which is often overlooked should be addressed to improve the prognostic outcomes in adolescence and adulthood.

Current and future nonstimulants in the treatment of pediatric ADHD: monoamine reuptake inhibitors, receptor modulators, and multimodal agents

Attention-deficit/hyperactivity disorder (ADHD), the single most common neuropsychiatric disorder with cognitive and behavioral manifestations, often starts in childhood and usually persists into adolescence and adulthood. Rarely seen alone, ADHD is most commonly complicated by other neuropsychiatric disorders that must be factored into any intervention plan to optimally address ADHD symptoms. With more than 30 classical Schedule II (CII) stimulant preparations available for ADHD treatment, only three nonstimulants (atomoxetine and extended-release formulations of clonidine and guanfacine) have been approved by the United States Food and Drug Administration (FDA), all of which focus on modulating the noradrenergic system. Given the heterogeneity and complex nature of ADHD in most patients, research efforts are identifying nonstimulants which modulate pathways beyond the noradrenergic system. New ADHD medications in clinical development include monoamine reuptake inhibitors, monoamine receptor modulators, and multimodal agents that combine receptor agonist/antagonist activity (receptor modulation) and monoamine transporter inhibition. Each of these "pipeline" ADHD medications has a unique chemical structure and differs in its pharmacologic profile in terms of molecular targets and mechanisms. The clinical role for each of these agents will need to be explored with regard to their potential to address the heterogeneity of individuals struggling with ADHD and ADHD-associated comorbidities. This review profiles alternatives to Schedule II (CII) stimulants that are in clinical stages of development (Phase 2 or 3). Particular attention is given to viloxazine extended-release, which has completed Phase 3 studies in children and adolescents with ADHD.

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.

Modulation of Spatial Memory Deficit and Hyperactivity in Dopamine Transporter Knockout Rats via α2A-Adrenoceptors

Attention deficit hyperactivity disorder (ADHD) is manifested by a specific set of behavioral deficits such as hyperactivity, impulsivity, and inattention. The dopamine neurotransmitter system is postulated to be involved in the pathogenesis of ADHD. Guanfacine, a selective α2A-adrenoceptor agonist, is prescribed for ADHD treatment. ADHD also is known to be associated with impairment of multiple aspects of cognition, including spatial memory, however, it remains unclear how modulation of the norepinephrine system can affect these deficits. Hyperdopaminergic dopamine transporter knockout (DAT-KO) rats are a valuable model for investigating ADHD. The DAT-KO rats are hyperactive and deficient in spatial working memory. This work aimed to evaluate the effects of noradrenergic drugs on the fulfillment of spatial cognitive tasks by DAT-KO rats. The rats were tested in the Hebb - Williams maze during training and following noradrenergic drugs administration. The efficiency of spatial orientation was assessed as to how fast the animal finds an optimal way to the goal box. Testing in a new maze configuration allowed us to evaluate the effects of drug administration after the acquisition of the task rules. The behavioral variables such as the distance traveled, the time to reach the goal box, and the time spent in the error zones were analyzed. It has been observed that α2A-adrenoceptor agonist Guanfacine (0.25 mg/kg) had only a minimal inhibitory effect on hyperactivity of DAT-KO rats in the maze but significantly ameliorated their perseverative pattern of activity and reduced the time spent in the error zones. In contrast, α2A-adrenoceptor antagonist Yohimbine, at the dose of 1 mg/kg, increased the distance traveled by DAT-KO rats and elevated the number of perseverative reactions and the time spent in the error zones. Guanfacine caused minimal effects in wild-type rats, while Yohimbine altered several parameters reflecting a detrimental effect on the performance in the maze. These data indicate that modulation of α2A-adrenoceptor activity potently affects both dopamine-dependent hyperactivity and cognitive dysfunctions. Similar mechanisms may be involved in the beneficial effects of Guanfacine on cognitive deficits in ADHD patients. This study further supports the translational potential of DAT-KO rats for testing new pharmacological drugs.

Practitioner's review: medication for children and adolescents with autism spectrum disorder (ASD) and comorbid conditions

Alleviating the multiple problems of children with autism spectrum disorder (ASD) and its comorbid conditions presents major challenges for the affected children, parents, and therapists. Because of a complex psychopathology, structured therapy and parent training are not always sufficient, especially for those patients with intellectual disability (ID) and multiple comorbidities. Moreover, structured therapy is not available for a large number of patients, and pharmacological support is often needed, especially in those children with additional attention deficit/hyperactivity and oppositional defiant, conduct, and sleep disorders.

Evidence-based pharmacological treatment options for ADHD in children and adolescents

Attention-deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity, causing functional impairment. Its prevalence lies at approximately 5% in children and adolescents and at approximately 2.5% in adults. The disorder follows a multifactorial etiology and shows a high heritability. Patients show a high interindividual and intraindividual variability of symptoms, with executive deficits in several cognitive domains. Overall, ADHD is associated with high rates of psychiatric comorbidities, and insufficient treatment is linked to adverse long-term outcomes. Current clinical guidelines recommend an individualized multimodal treatment approach including psychoeducation, pharmacological interventions, and non-pharmacological interventions. Available medications include stimulants (methylphenidate, amphetamines) and non-stimulants (atomoxetine, guanfacine, clonidine). While available pharmacological treatment options for ADHD show relatively large effect sizes (in short-term trials) and overall good tolerability, there is still a need for improvement of current pharmacotherapeutic strategies and for the development of novel medications. This review summarizes available pharmacological treatment options for ADHD in children and adolescents, identifies current issues in research and evidence gaps, and provides an overview of ongoing efforts to develop new medications for the treatment of ADHD in children and adolescents by means of a systematic cross-sectional analysis of the clinical trials registry www.clinicaltrials.gov.

Vitamin B6 deficiency hyperactivates the noradrenergic system, leading to social deficits and cognitive impairment

We have reported that a subpopulation of patients with schizophrenia have lower levels of vitamin B₆ (VB6) in peripheral blood than do healthy controls. In a previous study, we found that VB6 level was inversely proportional to the patient's positive and negative symptom scale (PANSS) score for measuring symptom severity, suggesting that the loss of VB6 might contribute to the development of schizophrenia symptoms. In the present study, to clarify the relationship between VB6 deficiency and schizophrenia, we generated VB6-deficient (VB6(-)) mice through feeding with a VB6-lacking diet as a mouse model for the subpopulation of schizophrenia patients with VB6 deficiency. After feeding for 4 weeks, plasma VB6 level in VB6(-) mice decreased to 3% of that in control mice. The VB6(-) mice showed social deficits and cognitive impairment. Furthermore, the VB6(-) mice showed a marked increase in 3-methoxy-4-hydroxyphenylglycol (MHPG) in the brain, suggesting enhanced noradrenaline (NA) metabolism in VB6(-) mice. We confirmed the increased NA release in the prefrontal cortex (PFC) and the striatum (STR) of VB6(-) mice through in vivo microdialysis. Moreover, inhibiting the excessive NA release by treatment with VB6 supplementation into the brain and α2A adrenoreceptor agonist guanfacine (GFC) suppressed the increased NA metabolism and ameliorated the behavioral deficits. These findings suggest that the behavioral deficits shown in VB6(-) mice are caused by enhancement of the noradrenergic (NAergic) system.

Understanding ADHD: Toward an Innovative Therapeutic Intervention

Attention deficit hyperactivity disorder (ADHD) is a pervasive condition affecting persons across all age groups, although it is primarily diagnosed in children. This neurological condition affects behavior, learning, and social adjustment and requires specific symptomatic criteria to be fulfilled for diagnosis. ADHD may be treated with a combination of psychological or psychiatric therapeutic interventions, but it often goes unattended. People with ADHD face societal bias challenges that impact how they manage the disorder and how they view themselves. This paper summarizes the present state of understanding of this disorder, with particular attention to early diagnosis and innovative therapeutic intervention. Contemporary understanding of the mind-brain duality allows for innovative therapeutic interventions based on neurological stimulation. This paper introduces the concept of neurostimulation as a therapeutic intervention for ADHD and poses the question of the relationship between patient adherence to self-administered therapy and the aesthetic design features of the neurostimulation device. By fabricating devices that go beyond safety and efficacy to embrace the aesthetic preferences of the patient, it is proposed that there will be improvements in patient adherence to a device intended to address ADHD.

Chronic Administrations of Guanfacine on Mesocortical Catecholaminergic and Thalamocortical Glutamatergic Transmissions

It has been established that the selective α2A adrenoceptor agonist guanfacine reduces hyperactivity and improves cognitive impairment in patients with attention-deficit/hyperactivity disorder (ADHD). The major mechanisms of guanfacine are considered to involve the activation of the postsynaptic α2A adrenoceptor of glutamatergic pyramidal neurons in the frontal cortex, but the effects of chronic guanfacine administration on catecholaminergic and glutamatergic transmissions associated with the orbitofrontal cortex (OFC) are yet to be clarified. The actions of guanfacine on catecholaminergic transmission, the effects of acutely local and systemically chronic (for 7 days) administrations of guanfacine on catecholamine release in pathways from the locus coeruleus (LC) to OFC, the ventral tegmental area (VTA) and reticular thalamic-nucleus (RTN), from VTA to OFC, from RTN to the mediodorsal thalamic-nucleus (MDTN), and from MDTN to OFC were determined using multi-probe microdialysis with ultra-high performance liquid chromatography. Additionally, the effects of chronic guanfacine administration on the expression of the α2A adrenoceptor in the plasma membrane fraction of OFC, VTA and LC were examined using a capillary immunoblotting system. The acute local administration of therapeutically relevant concentrations of guanfacine into the LC decreased norepinephrine release in the OFC, VTA and RTN without affecting dopamine release in the OFC. Systemically, chronic administration of therapeutically relevant doses of guanfacine for 14 days increased the basal release of norepinephrine in the OFC, VTA, RTN, and dopamine release in the OFC via the downregulation of the α2A adrenoceptor in the LC, OFC and VTA. Furthermore, systemically, chronic guanfacine administration did not affect intrathalamic GABAergic transmission, but it phasically enhanced thalamocortical glutamatergic transmission. The present study demonstrated the dual actions of guanfacine on catecholaminergic transmission-acute attenuation of noradrenergic transmission and chronic enhancement of noradrenergic transmission and thalamocortical glutamatergic transmission. These dual actions of guanfacine probably contribute to the clinical effects of guanfacine against ADHD.

Identification of Novel High-Affinity Substrates of OCT1 Using Machine Learning-Guided Virtual Screening and Experimental Validation

OCT1 is the most highly expressed cation transporter in the liver and affects pharmacokinetics and pharmacodynamics. Newly marketed drugs have previously been screened as potential OCT1 substrates and verified by virtual docking. Here, we used machine learning with transport experiment data to predict OCT1 substrates based on classic molecular descriptors, pharmacophore features, and extended-connectivity fingerprints and confirmed them by in vitro uptake experiments. We virtually screened a database of more than 1000 substances. Nineteen predicted substances were chosen for in vitro testing. Sixteen of the 19 newly tested substances (85%) were confirmed as, mostly strong, substrates, including edrophonium, fenpiverinium, ritodrine, and ractopamine. Even without a crystal structure of OCT1, machine learning algorithms predict substrates accurately and may contribute not only to a more focused screening in drug development but also to a better molecular understanding of OCT1 in general.

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.

Potential Role of ADRA2A Genetic Variants in the Etiology of ADHD Comorbid With Tic Disorders

Objective: To evaluate the role of the adrenergic receptor alpha-2A gene (ADRA2A) in the genetic etiology of ADHD comorbid with tic disorders (ADHD+TD). Method: Two single nucleotide polymorphisms (SNPs) of ADRA2A were genotyped and analyzed in 936 normal controls and 1,815 ADHD probands, including 1,249 trios. Approximately 16% of the ADHD probands also had a diagnosis of TD. Results: No significant association was found between ADRA2A and ADHD in general. Case-control analyses indicated different allelic and genotypic distributions of rs553668 between ADHD+TD and controls in males. Family-based association tests showed that the G allele of rs1800544, the A allele of rs553668, and the GA haplotype consisting of these two SNPs were overtransmitted in the ADHD+TD trios, especially in males. Moreover, the allelic/genotypic distribution and allelic transmission were different between ADHD+TD and ADHD without TD. Conclusion:ADRA2A may be associated with ADHD+TD, especially in males.

Efficacy of Guanfacine Extended Release in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder and Comorbid Oppositional Defiant Disorder

OBJECTIVE

To assess the efficacy of the non-stimulant guanfacine extended release (GXR) on attention-deficit/hyperactivity disorder (ADHD) symptoms in children and adolescents, with and without comorbid oppositional defiant disorder (ODD).

METHODS

Data were derived from 4 phase 3, randomized, placebo-controlled trials of dose-optimized GXR monotherapy, in which at least 10% of participants had a diagnosis of comorbid ODD. SPD503-312 and SPD503-316 were 10- to 13-week studies of GXR (1-7 mg/d). SPD503-314 and SPD503-307 were 8-week studies of GXR (1-4 mg/d). Efficacy was assessed using the ADHD Rating Scale IV (ADHD-RS-IV) total scores.

RESULTS

In total, 1,084 participants were included (SPD503-312 and SPD503-316, n = 537; SPD503-314, n = 333; and SPD503-307, n = 214). GXR was associated with significant improvements in ADHD core symptoms at endpoint in participants with and without ODD (p < 0.01 in all studies). Placebo-adjusted least-squares mean (95% confidence interval) changes from baseline to endpoint in the ADHD-RS-IV total scores in participants with and without ODD were -8.6 (-14.4, -2.8) and -7.3 (-9.5, -5.0) in the pooled data from SPD503-312 and SPD503-316, -12.6 (-19.6, -5.7) and -8.7 (-11.8, -5.5) in SPD503-314, and -12.7 (-17.3, -8.1) and -11.8 (-19.3, -4.4) in SPD503-307, respectively. The corresponding effect sizes were 0.688 and 0.598 in SPD503-312 and SPD503-316, 0.876 and 0.729 in SPD503-314, and 0.962 and 0.842 in SPD503-307.

CONCLUSION

The findings demonstrate the efficacy of GXR for treating ADHD in children and adolescents with comorbid ODD.

Current pharmacotherapy for tic disorders

Introduction: Though many unanswered questions about the pathophysiology of Tourette Syndrome remain, several pharmacotherapies for tics have been studied, with varying results in terms of efficacy and the strength of evidence.Areas covered: This literature review encompasses pharmacotherapies for tics. The pharmacotherapies discussed in this review include: alpha agonists, antipsychotics, topiramate, botulinum toxin, and dopamine depleters.Expert opinion: Once the presence of tics is confirmed and psychoeducation and support are provided to patients and caregivers, one must examine the degree of tic-related impairment and the presence of psychiatric comorbidities. These factors influence treatment decisions as the presence of comorbidity and related impairment may shift the treatment target. When selecting a medication for tics, the presence of ADHD (the most frequent comorbidity) strengthens the case for choosing an alpha agonist. The case for antipsychotic medications is strongest when tic-related impairment is severe and/or the tics are refractory to more conservative measures. All medications require drug safety monitoring procedures and reevaluation over time.

Development of the Korean Practice Parameter for Adult Attention-Deficit/Hyperactivity Disorder

OBJECTIVES

Adult attention-deficit/hyperactivity disorder (ADHD) is an important mental health problem that needs resolution, especially considering the high rates of ADHD continuation from childhood to adolescence/adulthood and the high prevalence of ADHD in adults. Adults with ADHD have lifelong negative impacts and require close monitoring with long-term follow-up. Hence, the establishment of a Korean practice parameter for adult ADHD is necessary to minimize discontinuation of treatment and enable information sharing among Korean mental health professionals.

METHODS

The Korean practice parameter was developed using an evidence-based approach consisting of expert consensus survey coupled with literature review.

RESULTS

According to the expert consensus survey, the most commonly used diagnostic methods were clinical psychiatric interview (20.66%) and self-report scales (19.25%) followed by attention (14.71%) and psychological tests (14.24%). Key evaluation instruments currently available in Korea are the World Health Organization Adult ADHD Self-Report Rating Scale, Korean Adult ADHD Rating Scale, Diagnostic Interview for ADHD in Adults, Barkley Deficits in Executive Functioning Scale for adults, Comprehensive Attention Test, Conners' Continuous Performance Test, and the subtests of Wechsler Adult Intelligence Scale, Digit Span and Letter-Number Sequencing. Although pharmacotherapy is recommended as the first-line of treatment for adult ADHD, we recommend that it be followed by a multimodal and multidisciplinary approach including psychoeducation, pharmacotherapy, cognitive behavior therapy and coaching.

CONCLUSION

The Korean practice parameter introduces not only general information for the diagnosis and treatment of adult ADHD on a global scale, but also the process of diagnosis and treatment options tailored to the Korean population.

A Phase II Double-Blind, Placebo-Controlled, Efficacy and Safety Study of SPN-812 (Extended-Release Viloxazine) in Children With ADHD

Objective: The objective of this study is to evaluate efficacy and safety of SPN-812 (extended-release viloxazine) for ADHD in children aged 6 to 12 years. Method: In an 8-week study, 222 participants were randomized to placebo or SPN-812 100, 200, 300, or 400 mg/day. Measurements included ADHD Rating Scale (RS)-IV total score and Clinical Global Impression-Severity (CGI-S) and Clinical Global Impression-Improvement (CGI-I) scores. Safety assessments included laboratory and electrocardiogram (ECG) measurements, suicidality monitoring (Columbia-Suicide Severity Rating Scale), and adverse event (AE) reporting. Results: Significant improvements in ADHD-RS-IV total score were observed for 200, 300, and 400 mg dose groups versus placebo (p < .05; effect size [ES] = 0.547, 0.596, and 0.623). CGI-I score for the 300 mg group and CGI-S score for all SPN-812 groups except for 100 mg improved significantly (p < .05) versus placebo. The most frequent AEs (≥15%) were somnolence, headache, and decreased appetite. Conclusion: SPN-812 significantly reduced the severity of ADHD symptoms and was well tolerated. The efficacy and safety of SPN-812 are being investigated in Phase III trials.

Metabolite profiling of guanfacine in plasma and urine of healthy Japanese subjects after oral administration of guanfacine extended-release tablets

Guanfacine is used for the treatment of attention‐deficit/hyperactivity disorder (ADHD). Using liquid chromatography–tandem mass spectrometry (LC–MS/MS), metabolite profiling of guanfacine was performed in plasma and urine collected from healthy Japanese adults following repeated oral administration of guanfacine extended‐release formulation. Unchanged guanfacine was the most abundant component in both plasma and urine (from the MS signal intensity). In plasma, the M3 metabolite (a sulfate of hydroxy‐guanfacine) was the prominent metabolite; the M2 metabolite (a glucuronide of a metabolite formed by monooxidation of guanfacine), 3‐hydroxyguanfacine and several types of glucuronide at different positions on guanfacine were also detected. In urine, the M2 metabolite and 3‐hydroxyguanfacine were the principal metabolites. From metabolite analysis, the proposed main metabolic pathway of guanfacine is monooxidation on the dichlorobenzyl moiety, followed by glucuronidation or sulfation. A minor pathway is glucuronidation at different positions on guanfacine. As the prominent metabolites in plasma were glucuronide and sulfate of hydroxyguanfacine, which have no associated toxicity concerns, further toxicity studies of the metabolites, for example in animals, were not deemed necessary.

Diving and attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is a psychiatric condition that affects attention, concentration, impulse control and awareness. Not only these symptoms, but also the medications used to treat ADHD (psychostimulants) pose a risk to both the diver and his or her buddy. This article presents guidelines for recreational diving in combination with ADHD and psychostimulants. These guidelines are based solely on 'expert' opinion and were adopted at a meeting of the Dutch Association for Diving Medicine in 2017.

Distinguishing the efficacy and sedative effects of guanfacine extended release in children and adolescents with attention-deficit/hyperactivity disorder

The present study investigated whether symptom reduction in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) treated with guanfacine extended release (GXR) can be explained by sedative effects of the medication. Data from four double-blind, randomized, placebo-controlled, phase 3 trials of GXR monotherapy (1-7 mg/day; morning administration) in children (aged 6-12 years) and adolescents (aged 13-17 years) with ADHD were analyzed post hoc. Two studies used forced-dose titration and two used flexible-dose titration. Efficacy was determined using ADHD Rating Scale IV (ADHD-RS-IV) scores. Sedative treatment-emergent adverse events (TEAEs) included somnolence, sedation and hypersomnia. The proportion of responders (≥ 30% reduction in ADHD-RS-IV total score) increased from weeks 1 to 4 and remained stable to study endpoint. Sedative TEAEs generally peaked at the first week in which the target dose was achieved and then declined. In subgroup analyses, significant placebo-adjusted improvements in ADHD-RS-IV total scores were observed in participants without any sedative TEAEs in the forced-dose and flexible-dose studies (nominal p < 0.001). In addition, GXR was associated with significant improvements in both inattentive and hyperactive-impulsive symptoms, as assessed by the ADHD-RS-IV subscale scores (nominal p < 0.001) and by the ADHD-RS-IV total score in participants with different ADHD subtypes (nominal p < 0.05). Thus, the efficacy of GXR in children and adolescents with ADHD is not primarily due to sedation, although some contribution to symptom reduction cannot be excluded, especially early in treatment when rates of sedative TEAEs are at their highest.

Effects of acute and sub-chronic administrations of guanfacine on catecholaminergic transmissions in the orbitofrontal cortex

The selective α2A adrenoceptor agonist guanfacine reduces hyperactivity and improves cognitive impairment in patients with attention-deficit/hyperactivity disorder (ADHD). The major mechanisms of guanfacine have been considered to involve activation of postsynaptic α2A adrenoceptor in frontal pyramidal neurons. However, the effects of chronic guanfacine administration on catecholaminergic transmissions associated with the orbitofrontal cortex (OFC) remain unclear. To explore the mechanisms of action of guanfacine on catecholaminergic transmission, the effects of its acute local or sub-chronic systemic administration on catecholamine release within pathways from locus coeruleus (LC) to OFC and reticular thalamic nucleus (RTN), from RTN to mediodorsal thalamic nucleus (MDTN), and from MDTN to OFC were determined using multi-probe microdialysis with ultra-high performance liquid chromatography. Acute OFC local administration of guanfacine did not affect catecholamine release in OFC. Acute LC local and sub-chronic systemic administrations of guanfacine reduced norepinephrine release in LC, OFC and RTN, and also reduced GABA release in MDTN, whereas AMPA-induced (perfusion with AMPA into NDTN) releases of l-glutamate, norepinephrine and dopamine in OFC were enhanced by sub-chronic systemic guanfacine administration. This study identified that catecholaminergic transmission is composed of three pathways: direct noradrenergic and co-releasing catecholaminergic LC-OFC pathways and intermediate LC-OFC (LC-RTN-MDTN-OFC) pathway. We demonstrated the dual actions of guanfacine on catecholaminergic transmission: attenuation of direct noradrenergic LC-OFC transmission at the resting stage and enhancement of direct co-releasing catecholaminergic LC-OFC transmission via GABAergic disinhibition in the intermediate LC-OFC pathway. These dual actions of guanfacine probably contribute to clinical actions of guanfacine against ADHD and its comorbid symptoms. This article is part of the Special Issue entitled 'Current status of the neurobiology of aggression and impulsivity'.

Lisdexamfetamine Dimesylate: A Review in Paediatric ADHD

Lisdexamfetamine dimesylate (lisdexamfetamine; Elvanse^®; Tyvense^®), an orally-active dexamfetamine prodrug, is indicated in the EU for the treatment of attention-deficit hyperactivity disorder (ADHD) in children aged ≥ 6 years (including adolescents) when the response to previous methylphenidate (MPH) treatment is clinically inadequate. The original approval of the drug was based on the results of phase III trials in children and adolescents with ADHD who had an inadequate response to previous pharmacotherapy (e.g. MPH) or were treatment naïve. In these studies, short-term treatment with flexibly-dosed lisdexamfetamine demonstrated greater efficacy than atomoxetine, based on a prospective comparison, and osmotic-release oral system (OROS)-MPH, based on a post hoc comparison. Improvements in ADHD symptoms were accompanied by improvements in health-related quality of life and functioning that were maintained as long as treatment with lisdexamfetamine was continued in a long-term extension of one of these trials. In subsequent phase IV head-to-head studies in adolescents with ADHD and an inadequate response to previous pharmacotherapy, lisdexamfetamine demonstrated greater efficacy than OROS-MPH when both medications were force-titrated, but not when they were flexibly-titrated. Lisdexamfetamine was generally well tolerated, with an adverse event profile (e.g. decreased appetite, headache, weight reduction, insomnia and irritability) typical of that reported for other stimulants. Thus, lisdexamfetamine provides an alternative option for the treatment of children and/or adolescents with ADHD who have not responded adequately to previous ADHD pharmacotherapies.

Pharmacoepidemiology of Tourette and Chronic Tic Disorders in Sweden 2005-2013

BACKGROUND

Monitoring "real world" dispensation patterns over time is important to build the evidence base for safe and efficient use of psychotropic drugs. In this study, we aimed to comprehensively examine the patterns of psychotropic drug dispensations in patients with Tourette and chronic tic disorders (TD/CTD) in Sweden between 2005 and 2013.

METHODS

A cohort of 6979 TD/CTD patients was identified through the Swedish National Patient Register. Their drug dispensation patterns, collected in the Swedish Prescribed Drug Register, were examined between July 1, 2005 and December 31, 2013. Frequencies of drug dispensations were further stratified by gender and comorbidities. Additionally, differences in the patterns of dispensation in children and adolescents versus adults in the last year of the follow-up were examined, as well as the time trends of the dispensations over the 8-year study period.

RESULTS

A total of 5299 (75.9%) TD/CTD patients were dispensed at least one drug during the study period. The most frequently dispensed medications were attention-deficit/hyperactivity disorder (ADHD) drugs (53.8%), antidepressants (50.7%), hypnotics/sedatives (41.7%), and antipsychotics (41.5%). Most of the medicated patients (72.1%) were dispensed more than one drug during the study period. Patterns of dispensation varied according to patient's gender, associated comorbidities, and age group. Dispensation of quetiapine and aripiprazole, antiadrenergics, ADHD drugs, antiepileptics, and hypnotics/sedatives and anxiolytics (particularly the nonbenzodiazepine types) significantly increased over time, whereas dispensation of antidepressants, typical antipsychotics, and benzodiazepine-based anxiolytics significantly decreased over the study period.

CONCLUSIONS

Long-term monitoring of these drug dispensation patterns and the study of both their beneficial and adverse effects is warranted.

Systemic administration of guanfacine improves food-motivated impulsive choice behavior primarily via direct stimulation of postsynaptic α2A-adrenergic receptors in rats

Impulsive choice behavior, which can be assessed using the delay discounting task, is a characteristic of various psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). Guanfacine is a selective α_2A-adrenergic receptor agonist that is clinically effective in treating ADHD. However, there is no clear evidence that systemic guanfacine administration reduces impulsive choice behavior in the delay discounting task in rats. In the present study, we examined the effect of systemic guanfacine administration on food-motivated impulsive choice behavior in rats and the neuronal mechanism underlying this effect. Repeated administration of either guanfacine, methylphenidate, or atomoxetine significantly enhanced impulse control, increasing the number of times the rats chose a large but delayed reward in a dose-dependent manner. The effect of guanfacine was significantly blocked by pretreatment with an α_2A-adrenergic receptor antagonist. Furthermore, the effect of guanfacine remained unaffected in rats pretreated with a selective noradrenergic neurotoxin, consistent with a post-synaptic action. In contrast, the effect of atomoxetine on impulsive choice behavior was attenuated by pretreatment with the noradrenergic neurotoxin. These results provide the first evidence that systemically administered guanfacine reduces impulsive choice behavior in rats and that direct stimulation of postsynaptic, rather than presynaptic, α_2A-adrenergic receptors is involved in this effect.

Pharmacokinetics, Safety, and Tolerability of Single and Multiple Doses of Guanfacine Extended-Release Formulation in Healthy Japanese and Caucasian Male Adults

BACKGROUND AND OBJECTIVE

Guanfacine extended-release (guanfacine XR) could be a useful treatment option for children and adolescent patients with attention-deficit/hyperactivity disorder (ADHD). As an initial step in the development in Japan, the pharmacokinetics, safety and tolerability were assessed in healthy Japanese and non-Hispanic Caucasian adults.

METHODS

A Phase 1, double-blind, randomized, placebo-controlled, single- and multiple-oral dose escalation study of guanfacine XR was conducted. Healthy Japanese and Caucasian subjects received guanfacine XR 1 mg orally in the morning on Day 1. Following safety assessments, subjects subsequently received guanfacine XR 1 mg (Days 4-8), 2 mg (Days 9-13), 3 mg (Days 14-18), and 4 mg (Days 19-23) once daily, followed by a taper-down period. Single- and multiple-dose pharmacokinetic parameters were estimated based on plasma concentration-time data and urine concentration data of guanfacine by non-compartmental analysis.

RESULTS

A total of 30 male subjects (15 Japanese and 15 Caucasian, active:placebo = 12:3) were enrolled. Of those receiving guanfacine XR, 11/12 (91.7%) subjects in each active drug group completed the study. Following multiple doses, the mean area under the plasma concentration-time curves of guanfacine were 9-22% greater for Caucasian subjects than Japanese subjects in the 1-3 mg dose range and 54% greater for the 4 mg. Guanfacine XR was generally well tolerated by both ethnic groups, with most adverse events being mild in both groups. There were no serious or severe adverse events during the study and no adverse events led to withdrawal from the study.

CONCLUSIONS

Exposure to guanfacine in Japanese subjects tended to be lower than in Caucasian subjects. Guanfacine XR was generally well tolerated and safety profiles were similar for Japanese and Caucasian subjects.

Safety, Tolerability and Efficacy of Drugs for Treating Behavioural Insomnia in Children with Attention-Deficit/Hyperactivity Disorder: A Systematic Review with Methodological Quality Assessment

OBJECTIVE

A large proportion of paediatric patients with attention-deficit/hyperactivity disorder (ADHD) have associated sleep problems which not only affect the child's wellbeing but also impact family functioning. Management of sleep problems is consequently an important aspect of overall ADHD management in paediatric patients. Although some drugs are being used off-label for the management of paediatric insomnia, there is scant clinical evidence supporting their use. Our aim was to identify and assess the quality of published studies reporting the safety, tolerability and efficacy of drugs used for treating behavioural insomnia in children with ADHD.

METHODS

After an initial screen to determine which drugs were most commonly used, we conducted a systematic review of English-language publications from searches of PubMed, EMBASE, PsycINFO and two trial register databases to February 2017, using keywords 'clonidine', 'melatonin', 'zolpidem', 'eszopiclone', 'L-theanine', 'guanfacine', 'ADHD', 'sleep disorder' and 'children'. For quality assessment of included studies, we used the CONSORT checklist for randomised control trials (RCTs) and the Downs and Black checklist for non-RCTs.

RESULTS

Twelve studies were included. Two case series for clonidine, two RCTs and four observational studies for melatonin and one RCT each for zolpidem, eszopiclone, L-theanine and guanfacine. Of the 12 included studies, only one on eszopiclone scored excellent for quality. The quality of the rest of the studies varied from moderate to low. For clonidine, melatonin and L-theanine, improvements in sleep-onset latency and total sleep duration were reported; however, zolpidem, eszopiclone and guanfacine failed to show any improvement when compared with placebo. Clonidine, melatonin, L-theanine, eszopiclone and guanfacine were well tolerated with mild to moderate adverse events; zolpidem was associated with neuropsychiatric adverse effects.

CONCLUSION

There is generally poor evidence for prescribing drugs for behavioural insomnia in children with ADHD. Further controlled studies are warranted.