A post hoc subgroup analysis of an 18-day randomized controlled trial comparing the tolerability and efficacy of mixed amphetamine salts extended release and atomoxetine in school-age girls with attention-deficit/hyperactivity disorder

A review of amphetamine extended release once-daily options for the management of attention-deficit hyperactivity disorder

INTRODUCTION

Amphetamine preparations are one of the two categories of stimulant medications approved for the treatment of attention deficit hyperactivity disorder (ADHD). Optimal treatment of ADHD aims to reduce core symptoms for as much of the waking hours as possible, leading to longer-acting delivery formats. In addition, the pediatric population commonly has difficulty swallowing pills and manufacturers have developed a variety of options to facilitate this concern. These include chewable tablets, capsules that may be sprinkled on soft food, liquids and transdermal patches.

AREAS COVERED

This article reviews the once-daily extended-release preparations currently available for amphetamine compounds, their pharmacodynamics, and common adverse effects.

EXPERT OPINION

There is an extensive evidence base supporting use of amphetamine preparations in the treatment of ADHD. Rapid onset of action and a favorable side effect profile make these widely used. The availability of once-daily extended-release chewable tablets, capsules that can be opened and sprinkled, and liquid formulations provides clinicians with multiple options to meet the specific needs of patients with difficulty swallowing whole pills.

The female side of pharmacotherapy for ADHD-A systematic literature review

OBJECTIVE

This comprehensive review examined sex differences in prescription rates and efficacy or effectiveness of pharmacotherapy treatment in girls and women with attention deficit hyperactivity disorder (ADHD), while identifying gaps in the scientific knowledge on this topic.

METHOD

A rigorous electronic database search was carried out in order to identify all published studies on female-specific effects of stimulants and non-stimulants in the treatment of ADHD. In total, 2672 studies were screened of which 21 studies (seven on prescription rates, 14 on effects of pharmacotherapy) met the inclusion criteria and were included for analysis.

RESULTS

In all seven studies on ADHD prescription rates, girls received significantly less prescriptions than boys, a difference however no longer seen in adults with the exception of one study. Each of the 14 studies on effectiveness / efficacy found at least one sex-difference in the effects of ADHD pharmacotherapy.

CONCLUSION

Several sex-differences are demonstrated in the prescription, usage and efficacy /effectiveness of both stimulant and non-stimulant ADHD pharmacotherapy. A single daily use of MPH may possibly not be optimal for girls with ADHD and ATX may be a promising medication for girls and women with ADHD. The robustness of this result requires further investigation.

Practitioner Review: Emotional dysregulation in attention-deficit/hyperactivity disorder - implications for clinical recognition and intervention

BACKGROUND

Because emotional symptoms are common in attention-deficit/hyperactivity disorder (ADHD) patients and associate with much morbidity, some consider it to be a core feature rather than an associated trait. Others argue that emotional symptoms are too nonspecific for use as diagnostic criteria. This debate has been difficult to resolve due, in part, to the many terms used to describe emotional symptoms in ADHD and to concerns about overlap with mood disorders.

METHODS

We sought to clarify the nature of emotional symptoms in ADHD by reviewing conceptual and measurement issues and by examining the evidence base regarding specificity of such symptoms for ADHD. We reviewed the various terms used to define emotional symptoms in ADHD, clarify how these symptoms are demarcated from mood disorders, and assess the possibility that symptoms of emotional impulsivity and deficient emotional self-regulation should be considered as core symptoms. We addressed psychiatric comorbidities, the effects of ADHD treatments on associated emotional dysregulation, and the utility of current rating scales to assess emotional symptoms associated with ADHD.

RESULTS

Emotional symptoms are common and persistent in youth and adults with ADHD. Although emotional symptoms are common in other psychiatric disorders, emotional impulsivity (EI), and deficient emotional self-regulation (DESR) may be sufficiently specific for ADHD to function as diagnostic criteria.

CONCLUSIONS

Emotional symptoms in ADHD cause clinically significant impairments. Although there is a solid theoretical rationale for considering EI and DESR to be core symptoms of ADHD, there is no consensus about how to define these constructs sin a manner that would be specific to the disorder. An instrument to measure EI and DESR which demarcates them from irritability and other emotional symptoms could improve the accuracy of diagnostic criteria for ADHD.

A Review of the Clinical Utility of Systematic Behavioral Observations in Attention Deficit Hyperactivity Disorder (ADHD)

This review evaluates the clinical utility of tools for systematic behavioral observation in different settings for children and adolescents with ADHD. A comprehensive search yielded 135 relevant results since 1990. Observations from naturalistic settings were grouped into observations of classroom behavior (n = 58) and of social interactions (n = 25). Laboratory observations were subdivided into four contexts: independent play (n = 9), test session (n = 27), parent interaction (n = 11), and peer interaction (n = 5). Clinically relevant aspects of reliability and validity of employed instruments are reviewed. The results confirm the usefulness of systematic observations. However, no procedure can be recommended as a stand-alone diagnostic method. Psychometric properties are often unsatisfactory, which reduces the validity of observational methods, particularly for measuring treatment outcome. Further efforts are needed to improve the specificity of observational methods with regard to the discrimination of comorbidities and other disorders.

The Safety of Atomoxetine for the Treatment of Children and Adolescents with Attention-Deficit/Hyperactivity Disorder: A Comprehensive Review of Over a Decade of Research

Atomoxetine is a noradrenergic reuptake inhibitor prescribed for attention-deficit/hyperactivity disorder (ADHD) that first gained approval in the USA in 2002 and has been authorized in 97 countries worldwide. The aim of this paper is to comprehensively review publications that addressed one or more of seven major safety topics relevant to atomoxetine treatment of children and adolescents (aged ≥6 years) diagnosed with ADHD. While the review focuses on children and adolescents, publications in which data from patients aged >18 years and from 6 to 18 years were analyzed in the same dataset were included. Using a predefined search strategy, including agreement of two reviewers when selecting papers, reduced the potential for bias. Using this process, we identified 70 eligible papers (clinical trials, epidemiological studies, and case reports) across the seven topics. We also referred to the European Summary of Product Characteristics (SPC) and US label. We found 15 papers about suicidality, three about aggression/hostility, seven about psychosis/mania, six about seizures, seven about hepatic effects, 29 about cardiovascular effects, and 28 about growth and development. The main findings (i.e., those from the largest and most well-conducted studies/analyses) are as follows. A large register-based study of pediatric and adult patients (6818 received atomoxetine) calculated a hazard ratio of 0.96 for suicide-related events during treatment with atomoxetine, and a meta-analysis of 23 placebo-controlled studies (N = 3883), published in 2014, found no completed suicides and no statistically significant association between atomoxetine and suicidality. The frequency of aggression/hostility was not statistically significantly higher with atomoxetine, e.g., experienced by 1.6 % (N = 21/1308) of atomoxetine-treated patients versus 1.1 % (N = 9/806) of placebo-treated patients in one meta-analysis. Symptoms of psychosis and mania were mainly observed in patients with comorbid bipolar disorder/depression. Based on spontaneous reports, during a 2-year period when 2.233 million adult and pediatric patients were exposed to atomoxetine, the reporting rate for seizures was 8 per 100,000 patients. In the manufacturer's database, atomoxetine was a "probable cause" of three hepatic adverse events (AEs) (all reversible hepatitis), and 133 hepatic AEs had possible confounding factors and were "possibly related" to atomoxetine, during 4 years when atomoxetine exposure had reached about 4.3 million patients. Rare cases of severe liver injury are described in the US label and European SPC; a case requiring liver transplantation is described in the US label. In a comprehensive review of a clinical trials database (N = 8417 received atomoxetine), most pediatric patients experienced modest increases in heart rate and blood pressure, and 8-12 % experienced more pronounced changes (≥20 bpm, ≥15 to 20 mmHg). However, in three long-term analyses (≥2 years), blood pressure was within age norms, and few patients discontinued due to cardiovascular AEs. As described in the European SPC, QT interval prolongation is uncommon, e.g., in an open-label study, 1.4 % of 711 children and adolescents had prolonged QTc intervals (≥450 ms in males, ≥470 ms in females) that were not clinically significant at ≥3 years of treatment with atomoxetine. The European SPC warns about potential QT interval prolongation in patients with a personal or family history, or if atomoxetine is administered with other drugs that potentially affect the QT interval. Decreases in growth (weight and height gain) occurred and were greatest in patients of above average weight and height, but appeared to recover over 2-5 years of atomoxetine treatment. In conclusion, suicidality, aggression/hostility, psychosis, seizures, liver injuries, and prolonged QT interval are uncommon or rare in children and adolescents treated with atomoxetine, based on data from the predefined search and from the European SPC. Overall, the data that we assessed from our search do not suggest that associations exist between atomoxetine and suicidality or seizures. The data also suggest that an association may not exist between atomoxetine and aggression/hostility. While atomoxetine may affect the cardiovascular system, the data suggest these effects are not clinically significant in most patients. Reductions in growth appear to be reversible in the long term.

Amphetamines for attention deficit hyperactivity disorder (ADHD) in children and adolescents

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most common psychiatric conditions affecting children and adolescents. Amphetamines are among the most commonly prescribed medications to manage ADHD. There are three main classes of amphetamines: dexamphetamine, lisdexamphetamine and mixed amphetamine salts, which can be further broken down into short- and long-acting formulations. A systematic review assessing their efficacy and safety in this population has never been conducted.

OBJECTIVES

To assess the efficacy and safety of amphetamines for ADHD in children and adolescents.

SEARCH METHODS

In August 2015 we searched CENTRAL, Ovid MEDLINE, Embase, PsycINFO, ProQuest Dissertation and Theses, and the Networked Digital Library of Theses and Dissertations. We also searched ClinicalTrials.gov, and checked the reference lists of relevant studies and reviews identified by the searches. No language or date restrictions were applied.

SELECTION CRITERIA

Parallel-group and cross-over randomized controlled trials (RCTs) comparing amphetamine derivatives against placebo in a pediatric population (< 18 years) with ADHD.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data on participants, settings, interventions, methodology, and outcomes for each included study. For continuous outcomes, we calculated the standardized mean difference (SMD) and for dichotomous outcomes we calculated the risk ratio (RR). Where possible, we conducted meta-analyses using a random-effects model. We also performed a meta-analysis of the most commonly reported adverse events in the primary studies.

MAIN RESULTS

We included 23 trials (8 parallel-group and 15 cross-over trials), with 2675 children aged three years to 17 years. All studies compared amphetamines to placebo. Study durations ranged from 14 days to 365 days, with the majority lasting less than six months. Most studies were conducted in the United States; three studies were conducted across Europe. We judged 11 included studies to be at a high risk of bias due to insufficient blinding methods, failing to account for dropouts and exclusions from the analysis, and failing to report on all outcomes defined a priori. We judged the remaining 12 studies to be at unclear risk of bias due to inadequate reporting.Amphetamines improved total ADHD core symptom severity according to parent ratings (SMD -0.57; 95% confidence interval (CI) -0.86 to -0.27; 7 studies; 1247 children/adolescents; very low quality evidence), teacher ratings (SMD -0.55; 95% CI -0.83 to -0.27; 5 studies; 745 children/adolescents; low quality evidence), and clinician ratings (SMD -0.84; 95% CI -1.32 to -0.36; 3 studies; 813 children/adolescents; very low quality evidence). In addition, the proportion of responders as rated by the Clinical Global Impression - Improvement (CGI-I) scale was higher when children were taking amphetamines (RR 3.36; 95% CI 2.48 to 4.55; 9 studies; 2207 children/adolescents; very low quality evidence).The most commonly reported adverse events included decreased appetite, insomnia/trouble sleeping, abdominal pain, nausea/vomiting, headaches, and anxiety. Amphetamines were associated with a higher proportion of participants experiencing decreased appetite (RR 6.31; 95% CI 2.58 to 15.46; 11 studies; 2467 children/adolescents), insomnia (RR 3.80; 95% CI 2.12 to 6.83; 10 studies; 2429 children/adolescents), and abdominal pain (RR 1.44; 95% CI 1.03 to 2.00; 10 studies; 2155 children/adolescents). In addition, the proportion of children who experienced at least one adverse event was higher in the amphetamine group (RR 1.30; 95% CI 1.18 to 1.44; 6 studies; 1742 children/adolescents; low quality evidence).We performed subgroup analyses for amphetamine preparation (dexamphetamine, lisdexamphetamine, mixed amphetamine salts), amphetamine release formulation (long acting versus short acting), and funding source (industry versus non industry). Between-group differences were observed for proportion of participants experiencing decreased appetite in both the amphetamine preparation (P < 0.00001) and amphetamine release formulation (P value = 0.008) subgroups, as well as for retention in the amphetamine release formulation subgroup (P value = 0.03).

AUTHORS' CONCLUSIONS

Most of the included studies were at high risk of bias and the overall quality of the evidence ranged from low to very low on most outcomes. Although amphetamines seem efficacious at reducing the core symptoms of ADHD in the short term, they were associated with a number of adverse events. This review found no evidence that supports any one amphetamine derivative over another, and does not reveal any differences between long-acting and short-acting amphetamine preparations. Future trials should be longer in duration (i.e. more than 12 months), include more psychosocial outcomes (e.g. quality of life and parent stress), and be transparently reported.

Impact of Attention-Deficit Hyperactivity Disorder on School Performance: What are the Effects of Medication?

Attention-deficit hyperactivity disorder (ADHD) affects an estimated 5-7 % of schoolchildren worldwide. School functioning and academic achievement are frequently impaired by ADHD and represent one of the main reasons children start ADHD medication. Multiple potential causal pathways exist between ADHD and impaired school performance. In this review, we decompose school performance into three components and assess the impact of ADHD and its treatments on academic performance (assessed by grade point average [GPA], time on-task, percentage of work completed as well as percent completed correctly), academic skills (as measured by achievement tests and cognitive measures), and academic enablers (such as study skills, motivation, engagement, classroom behavior and interpersonal skills). Most studies examined only the short-term effects of medication on school performance. In these, ADHD medications have been observed to improve some aspects of school performance, with the largest impact on measures of academic performance such as seatwork productivity and on-task performance. In a subset of children, these benefits may translate into detectable improvements in GPA and achievement testing. However, limited data exists to support whether these changes are sustained over years. Optimizing medication effects requires periodic reassessment of school performance, necessitating a collaborative effort involving patients, parents, school staff and prescribers. Even with systematic reassessment, behavioral-based treatments and additional school-based services may be needed to maximize academic performance for the many youth with ADHD and prominent impairments in school performance.

The efficacy of atomoxetine for the treatment of children and adolescents with attention-deficit/hyperactivity disorder: a comprehensive review of over a decade of clinical research

Atomoxetine was first licensed to treat attention-deficit/hyperactivity disorder (ADHD) in children and adolescents in the US in 2002. The aim of this paper is to comprehensively review subsequent publications addressing the efficacy of atomoxetine in 6- to 18-year-olds with ADHD. We identified 125 eligible papers using a predefined search strategy. Overall, these papers demonstrate that atomoxetine is an effective treatment for the core ADHD symptoms (effect sizes 0.6-1.3, vs. placebo, at 6-18 weeks), and improves functional outcomes and quality of life, in various pediatric populations with ADHD (i.e., males/females, patients with co-morbidities, children/adolescents, and with/without prior exposure to other ADHD medications). Initial responses to atomoxetine may be apparent within 1 week of treatment, but can take longer (median 23 days in a 6-week study; n=72). Responses often build gradually over time, and may not be robust until after 3 months. A pooled analysis of six randomized placebo-controlled trials (n=618) indicated that responses at 4 weeks may predict response at 6-9 weeks, although another pooled analysis of open-label data (n=338) suggests that the probability of a robust response to atomoxetine [≥40% decrease in ADHD-Rating Scale (ADHD-RS) scores] may continue to increase beyond 6-9 weeks. Atomoxetine may demonstrate similar efficacy to methylphenidate, particularly immediate-release methylphenidate, although randomized controlled trials are generally limited by short durations (3-12 weeks). In conclusion, notwithstanding these positive findings, before initiating treatment with atomoxetine, it is important that the clinician sets appropriate expectations for the patient and their family with regard to the likelihood of a gradual response, which often builds over time.

Amphetamine, past and present--a pharmacological and clinical perspective

Amphetamine was discovered over 100 years ago. Since then, it has transformed from a drug that was freely available without prescription as a panacea for a broad range of disorders into a highly restricted Controlled Drug with therapeutic applications restricted to attention deficit hyperactivity disorder (ADHD) and narcolepsy. This review describes the relationship between chemical structure and pharmacology of amphetamine and its congeners. Amphetamine's diverse pharmacological actions translate not only into therapeutic efficacy, but also into the production of adverse events and liability for recreational abuse. Accordingly, the balance of benefit/risk is the key challenge for its clinical use. The review charts advances in pharmaceutical development from the introduction of once-daily formulations of amphetamine through to lisdexamfetamine, which is the first d-amphetamine prodrug approved for the management of ADHD in children, adolescents and adults. The unusual metabolic route for lisdexamfetamine to deliver d-amphetamine makes an important contribution to its pharmacology. How lisdexamfetamine's distinctive pharmacokinetic/pharmacodynamic profile translates into sustained efficacy as a treatment for ADHD and its reduced potential for recreational abuse is also discussed.

The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): what every clinician should know

This review, addressed mainly to clinicians, considers commonly asked questions related to the neuroimaging, neurophysiology, neurochemistry and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD). It provides answers based on the most recent meta-analyses and systematic reviews, as well as additional relevant original studies. Empirical findings from neurobiological research into ADHD reflect a shift in the conceptualisation of this disorder from simple theoretical views of a few isolated dysfunctions to more complex models integrating the heterogeneity of the clinical manifestations of ADHD. Thus, findings from structural and functional neuroimaging suggest the involvement of developmentally abnormal brain networks related to cognition, attention, emotion and sensorimotor functions. Brain functioning alterations are confirmed by neurophysiological findings, showing that individuals with ADHD have elevated theta/beta power ratios, and less pronounced responses and longer latencies of event-related potentials, compared with controls. At a molecular level, alterations in any single neurotransmitter system are unlikely to explain the complexity of ADHD; rather, the disorder has been linked to dysfunctions in several systems, including the dopaminergic, adrenergic, serotoninergic and cholinergic pathways. Genetic studies showing a heritability of ∼60-75% suggest that a plethora of genes, each one with a small but significant effect, interact with environmental factors to increase the susceptibility to ADHD. Currently, findings from neurobiological research do not have a direct application in daily clinical practice, but it is hoped that in the near future they will complement the diagnostic process and contribute to the long-term effective treatment of this impairing condition.

Resilience in Families Living with a Child Diagnosed with Hyperactivity/Attention Deficit Disorder

There has been limited South African research to date on family resilience as well as on the resiliency of families living with children diagnosed with AD/HD. We aimed to explore and describe the factors that facilitate adjustment and adaptation in families after a child has been clinically diagnosed with AD/HD. The Resiliency Model of Family Stress, Adjustment and Adaptation served as a framework to conceptualize the families' adjustment and adaptation processes. The study was triangular in nature, with an exploratory, descriptive approach. Non-probability purposive sampling was used to gain participants for the study. A biographical questionnaire and seven structured questionnaires were used to gather data. The biographical data were analysed using descriptive statistics. Quantitative data were analysed by means of correlation analysis, and content analysis was used to analyse the qualitative data obtained from the open-ended question on the biographical questionnaire. While the results of the quantitative analysis and qualitative analysis yielded various results, some commonalities can be highlighted; social support, family time and routines, and incendiary (affirmative) communication. The study sample also demonstrated their ability to bounce back from the adversities that previous research consistently highlighted as difficulties in their context. The findings of the research can be incorporated into individual and family level interventions for families living with a child diagnosed with AD/HD.

The neuropharmacology of ADHD drugs in vivo: insights on efficacy and safety

Results from in vivo techniques, especially intracerebral microdialysis in freely-moving rats, have provided insights into potential mechanisms responsible for the efficacy and safety of catecholaminergic drugs for ADHD treatment. The drugs reviewed come from distinct pharmacological classes: psychostimulant releasing agents, eg d-amphetamine; psychostimulant reuptake inhibitors, eg dl-threo-methylphenidate (dl-MPH), and non-stimulant reuptake inhibitors, eg atomoxetine. Psychostimulants, which currently deliver the best efficacy in treating ADHD, exhibit the following characteristics on extraneuronal catecholamine concentrations in rodent brain in vivo: 1) They enhance the efflux and function of both noradrenaline and dopamine in the central nervous system. 2) The increase of dopamine efflux that they produce is not limited to cortical regions. 3) They have a rapid onset of action with no ceiling on drug effect. d-Amphetamine has a mechanism independent of neuronal firing rate, displacing intraneuronal stores of catecholamines, delaying their reuptake and inhibiting catabolism by monoamine oxidase. dl-MPH has an enigmatic, extraneuronal action that is neuronal firing rate-dependent and reuptake transporter-mediated, yet paradoxically, almost as powerful as that of d-amphetamine. In safety terms, these powerful catecholaminergic effects also make the psychostimulants liable for abuse. Since efficacy and safety derive from the same pharmacological mechanisms, it has not yet been possible to separate these two components. However, the development of once-daily psychostimulant formulations and a prodrug, lisdexamfetamine, has improved patient compliance and markedly reduced scope for their diversion/abuse. This review will discuss the in vivo pharmacological profiles of approved catecholaminergic drugs for treatment of ADHD and implications for their clinical efficacy and abuse liability.

Efficacy and safety of atomoxetine for attention-deficit/hyperactivity disorder in children and adolescents-meta-analysis and meta-regression analysis

OBJECTIVES

The objective of this study was to evaluate the efficacy and safety of atomoxetine in children and adolescents.

MATERIALS AND METHODS

We searched for studies published between 1985 and 2006 through Medline, PubMed, PsychInfo and Cochrane Central Register of Controlled Trials (CENTRAL 2006 Issue 3) using keywords related to atomoxetine and attention-deficit/hyperactivity disorder (ADHD) and scanned though reference lists. We included nine randomized placebo-controlled trials (atomoxetine:placebo = 1,150:678).

RESULTS

Atomoxetine was superior (p < 0.01) to placebo in reducing ADHD symptoms across different scales (Attention-Deficit/Hyperactivity Disorder Rating Scale-IV, Conners' Parent and Teacher Rating Scales-Revised:Short Form, Clinical Global Impression-Severity) rated by different raters (parent, teacher, clinician). The number-needed-to-treat (NNTs) for treatment response and relapse prevention were 3.43 (95% CI, 2.79-4.45) and 10.30 (95% CI, 5.89-40.62), respectively. High baseline ADHD symptoms (p = 0.02) was associated with greater reduction in ADHD symptoms, whereas male gender (p = 0.02), comorbid oppositional defiant disorder (ODD) status (p = 0.01) and ADHD hyperactive/impulsive subtype (p = 0.01) were associated with smaller reductions. The commonest adverse events were gastrointestinal [appetite decrease, number-needed-to-harm (NNH) = 8.81; abdominal pain, NNH = 22.48; vomiting, NNH = 29.96; dyspepsia, NNH = 49.38] and sleep related (somnolence, NNH = 19.41). Young age (p = 0.03) and high baseline hyperactive/impulsive symptoms (p < 0.01) were associated with more adverse events, whereas ADHD inattentive subtype (p = 0.04) was associated with less adverse events. Quality of life using Child Health Questionnaire (CHQ) improved (p < 0.01) with atomoxetine treatment. Both ADHD and ODD symptoms (p < 0.01) were reduced in comorbid ADHD+ODD, and ODD status was not associated with more adverse events. Efficacy and side effects were not altered by comorbid general anxiety disorder or major depression.

CONCLUSIONS

Atomoxetine is efficacious in reducing ADHD symptoms. It may have a role in treating comorbid ODD or depression, and probably in comorbid anxiety.

Review of long-acting stimulants in the treatment of attention deficit hyperactivity disorder

A number of long-acting medications for the treatment of attention deficit hyperactivity disorder (ADHD) have recently been developed and approved for use in the US. These compounds are intended to optimize and maintain ADHD symptom control throughout the day, while eliminating problems associated with short-acting medications, such as the need for in-school, midday or multiple daily doses. Recent reports confirm that the safety and tolerability of long-acting medications are similar to those of short-acting medications, although long-acting medications appear to have a lower risk of abuse and diversion and may be associated with significant improvements in medication adherence. Distinctions can be made among the long-acting medications with regard to the onset, magnitude and duration of their clinical effects. Recognition of these differences is important for individualizing treatment for patients with ADHD.

Pharmacologic Treatment of Attention-Deficit/Hyperactivity Disorder: Efficacy, Safety and Mechanisms of Action

Studies examining the efficacy, safety and mechanisms of action of agents for the treatment of attention-deficit/hyperactivity disorder (ADHD) are reviewed, with an emphasis on newer agents such as the long acting stimulants and atomoxetine. Recent studies of medications are characterized by large, rigorously diagnosed samples of children, adolescents and adults with ADHD, use of standardized rating scales and extensive safety data. These studies confirm a robust treatment effect for the Food and Drug Administration approved agents ranging from 0.7 to 1.5. The most common short term side effects to the most commonly used agents include insomnia, loss of appetite, and headaches. Despite public controversy and labeling changes to warn of extremely rare cardiovascular and psychiatric side effects, the evidence does not support the hypothesis that medication for ADHD increases risk for sudden death, mania or psychosis. A wide variety of neuroimaging techniques including electrocephalogram (EEG) power, event related potentials (ERP), functional magnetic resonance imaging (fMRI), and positron emission tomography (PET) are beginning to examine the mechanisms of action of medications for ADHD, and implicating the catecholamines and prefrontal and anterior cingulate cortices as prime sites of actions for these agents.

Atomoxetine for hyperactivity in autism spectrum disorders: placebo-controlled crossover pilot trial

OBJECTIVE

To explore placebo-controlled efficacy and safety of atomoxetine (ATX) for attention-deficit/hyperactivity disorder (ADHD) symptoms in children with autism spectrum disorders (ASD).

METHOD

Children ages 5 to 15 with ASD and prominent ADHD symptoms were randomly assigned to order in a crossover of clinically titrated ATX and placebo, 6 weeks each, separated by 1-week washout. Slopes for each condition were compared by paired t test.

RESULTS

In 2004-2005, 12 boys and 4 girls (7 with autistic disorder, 1 Asperger's, 8 pervasive developmental disorder not otherwise specified) all completed at least 3 weeks of each condition. On the primary outcome, the Hyperactivity subscale of the Aberrant Behavior Checklist, ATX was superior to placebo (p =.043, effect size d = 0.90). It was also superior on a 0 to 3 rating of nine DSM-IV ADHD hyperactive/impulsive symptoms (p =.005, d = 1.27), but missed significance on nine inattentive symptoms (p =.053, d= 0.89). Nine subjects responded to ATX, four to placebo (25% improvement on the Hyperactivity subscale plus Clinical Global Impressions-Improvement of 1-2. One was rehospitalized for recurrent violence on ATX. Adverse events were otherwise tolerable, with no tendency to stereotypy.

CONCLUSIONS

ATX appears safe and effective for treating hyperactivity in some children with autism spectrum disorders. The effect appears as large as in a multisite methylphenidate trial in the same population, with fewer intolerable side effects. Further study in autism spectrum disorders is indicated.