Understanding the Effects of Stimulant Medications on Cognition in Individuals with Attention-Deficit Hyperactivity Disorder: A Decade of Progress

The use of stimulant drugs for the treatment of children with attention-deficit hyperactivity disorder (ADHD) is one of the most widespread pharmacological interventions in child psychiatry and behavioral pediatrics. This treatment is well grounded on controlled studies showing efficacy of low oral doses of methylphenidate and amphetamine in reducing the behavioral symptoms of the disorder as reported by parents and teachers, both for the cognitive (inattention and impulsivity) and non-cognitive (hyperactivity) domains. Our main aim is to review the objectively measured cognitive effects that accompany the subjectively assessed clinical responses to stimulant medications. Recently, methods from the cognitive neurosciences have been used to provide information about brain processes that underlie the cognitive deficits of ADHD and the cognitive effects of stimulant medications. We will review some key findings from the recent literature, and then offer interpretations of the progress that has been made over the past decade in understanding the cognitive effects of stimulant medication on individuals with ADHD.     

Long-term efficacy and safety of treatment with stimulants and atomoxetine in adult ADHD: A review of controlled and naturalistic studies

Attention-deficit/hyperactivity disorder (ADHD) is a common disorder of childhood that often persists into adulthood. Although stimulant medications are recommended as the first-line treatment for ADHD because of their documented short-term effects in children and adults, less is known about their effects on long-term outcome in adults. Here we review the long-term efficacy and safety of the stimulant drugs methylphenidate and amphetamine, as well as the related compound atomoxetine. We performed a systematic review to identify direct and indirect effects of stimulant therapy on long-term outcome in adults. Five randomized controlled trials (RCTs), and 10 open-label extension studies of initial short-term RCTs, with total follow-up of at least 24 weeks, were identified. All these RCTs found that medication was significantly more efficacious than placebo in treating ADHD in adults, and the extension studies showed that this favorable effect of medication was maintained during the open-label follow-up period. However, since the maximum duration of these pharmacological trials was 4 years, we also reviewed 18 defined naturalistic longitudinal and cross-sectional studies, to provide more information about longer term functional outcomes, side effects and complications. These observational studies also showed positive correlations between early recognition of the disorder, stimulant treatment during childhood and favorable long-term outcome in adult ADHD patients. In conclusion, stimulant therapy of ADHD has long-term beneficial effects and is well tolerated. However, more longitudinal studies of long duration should be performed. In addition, the ethical issues involved in performing double blind RCTs of many years duration should be further explored.     

Background,clinical features and treatment of attention deficit hyperactivity disorder in children

Introduction: Attention deficit hyperactivity disorder (ADHD) is an early onset, clinically heterogeneous, complex neurobiological disorder, defined by symptoms of inattention and hyperactivity/impulsivity and has been associated with a broad range of impairments for those affected. Additionally, ADHD in children and adolescents is frequently associated with psychiatric comorbidities. This review provides an overview of the epidemiology, neurobiology, genetics, diagnosis and most recent pharmacological approaches for treatment with a focus on safety and efficacy and describes the use of medications used to treat ADHD in special populations.

Areas covered: PubMed, Cochrane database, Essential Evidence and Uptodate were searched for relevant articles about stimulant and non-stimulant pharmacological approaches in ADHD.

Expert opinion: Data supporting the safety and efficacy of both stimulant and non-stimulant formulations have significantly grown over the past decade and more efforts are being made to tailor medications to the needs of the patients and their families. Pharmacogenomics research is evolving, but predictors of treatment response and side effects remain largely unknown. Other unmet clinical needs include long-term follow-up studies of the safety and efficacy of medications for those with ADHD alone, or with comorbidities and in special populations including preschoolers.     

Management of treatment refractory attention-deficit/hyperactivity disorder in children and adolescents

Psychostimulants are the first-line treatment for attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. A minimum of two psychostimulant trials should be instituted before a child's symptoms of ADHD are considered treatment refractory. Clinical issues of diagnostic accuracy, comorbid disorders, psychosocial factors, medication compliance, symptoms across settings, and behavioral treatment should be addressed before initiating alternative medication trials. With the exception of tricyclic antidepressants, there is a paucity of controlled studies with adequate sample size to support the efficacy and safety of nonstimulant medications for the treatment of childhood ADHD. In this article, data on medications for treatment refractory ADHD in children and adolescents are presented and treatment strategies are discussed.     

Efficacy and tolerability of pharmacotherapies for attention-deficit hyperactivity disorder in adults

This review examines the evidence regarding the efficacy and tolerability of long- and short-acting stimulant medications, as well as the non-stimulant medications atomoxetine and bupropion in the treatment of adult attention-deficit hyperactivity disorder (ADHD). Effect sizes in adults appear to be of almost the same magnitude as in school-age children when robust doses are used. There are adequate data demonstrating short-term efficacy and safety of medication in ADHD during adulthood but long-term studies are lacking, particularly in view of concerns regarding cardiovascular adverse events. There is some evidence that stimulant medication can improve driving performance in adults with ADHD. The extent to which medication may improve academic, occupational and social functioning in adults with ADHD is unclear, and future research should investigate these outcomes. Medication treatment of adults with ADHD in sports is controversial. Both stimulant and non-stimulant medications seem to be well tolerated. Monitoring of pulse and blood pressure is recommended with these drugs because of their cardiovascular effects. There have been extremely rare case reports of sudden death in adults and children treated with stimulants and atomoxetine, but it is difficult to clearly establish causality. In view of reports of treatment-related suicide-related behaviour with atomoxetine, it is recommended that adults should be observed for agitation, irritability, suicidal thinking, self-harming or unusual behaviour, particularly in the first months of treatment, or after a change of dose. ADHD in adults continues to remain an under-recognized disorder in many parts of the world and there is a lack of specialist clinics for assessment and treatment of adult ADHD. Studies to date have failed to show efficacy of medications in the treatment of ADHD in the substance misuse population. There is little evidence so far to suggest an increased misuse of stimulants or diversion amongst substance misusers; however, data are insufficient to draw firm conclusions. Further work is necessary to evaluate effective treatments in subgroups such as the substance misuse population, those with multiple co-morbidities and different ADHD subtypes.     

Pharmacotherapy of adolescent attention deficit hyperactivity disorder: challenges, choices and caveats

A recent increase in stimulant treatment of adolescents with attention deficit hyperactivity disorder (ADHD) has been documented. Challenges in treating adolescent ADHD with methylphenidate or dextroamphetamine include compliance with frequent dosing, abuse potential and wear-off or rebound effects. Co-morbid anxiety, occurring in at least 30 percent of ADHD youths, is associated with lower rate of response to stimulants. The effective alternatives, tricyclic antidepressants or pemoline, are each associated with rare but serious toxicity. Bupropion has recently proven effective in controlled trials. Other noradrenergic or dopamine-enhancing agents such as venlafaxine and nicotine show some benefit in open trials. The need for more options in pharmacotherapy of ADHD is evidenced by rapid adoption in clinical practice of alternative and adjunctive medication despite lack of controlled research on efficacy and safety. The indications for long-term stimulant treatment of ADHD present some controversy, and highlight a need for more research on safety and efficacy through the lifespan. Thresholds for diagnosis are much lower with DSM than with ICD, and thresholds for treatment are contentious, given the performance-enhancing effects of stimulants in normal students. The endpoint for treatment is unclear, as stimulants are also effective in adult ADHD. Based on short- and intermediate-term studies to date, stimulant medication is clearly more efficacious than cognitive and behavioral strategies for the symptoms of ADHD. Longer term research is needed to determine whether sustained stimulant therapy will reduce the adverse emotional, behavioral and academic consequences of inattention and impulsivity in adolescents and adults.     

Dexmethylphenidate for attention deficit hyperactivity disorder

Background: Dexmethylphenidate is a single-isomer stimulant medication approved for the treatment of attention deficit hyperactivity disorder (ADHD). Single-isomer drugs have the potential for decreased undesired effects and improved therapeutic efficacy. Stimulant medications have been the mainstay treatments for ADHD for fifty years, and ability to reduce their adverse effects would be useful in promoting patient compliance with treatment. Objective: To review the literature on the safety and efficacy of dexmethylphenidate. Methods: MedLine, PubMed search of dexmethylphenidate research. Results/conclusions: Dexmethylphenidate is a safe and effective treatment for ADHD. Its overall safety and tolerability profile is similar to other members of the psychostimulant class.     

盐酸哌甲酯控释片治疗注意缺陷多动障碍研究进展

注意缺陷多动障碍是一种儿童期常见的精神障碍，中枢兴奋剂如盐酸哌甲酯片是临床治疗此类障碍的一线药物。然而，由于盐酸哌甲酯片疗效持续时间较短，需要每天多次服药使治疗依从性不佳。盐酸哌甲酯控释片（专注达）是每天1次服用的渗透型控释片剂，成为治疗注意缺陷多动障碍的有价值药物。现综述其药动学、药理作用、剂型特点、临床疗效和安全性研究进展。     

Lisdexamfetamine dimesylate: a new therapeutic option for attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is associated with substantial functional, clinical and economic burdens. It is among the most common psychiatric disorders in children and adolescents, and often persists into adulthood. Both medication and psychosocial interventions are recommended for the treatment of ADHD. However, ADHD treatment practices vary considerably, depending on medication availability, reimbursement and the evolution of clinical practice in each country. In Europe, stimulants and atomoxetine are widely available medications for the treatment of ADHD, whereas in the US approved treatment options also include extended-release formulations of clonidine and guanfacine. Lisdexamfetamine dimesylate (lisdexamfetamine) is a long-acting, prodrug formulation of dexamfetamine. It is currently licensed in the US, Canada and Brazil, and is undergoing phase III studies in Europe. We performed a PubMed/MEDLINE search looking for recent (2005-2012) scientific papers regarding the pharmacokinetics, pharmacodynamics, efficacy and safety of lisdexamfetamine. The lisdexamfetamine molecule is therapeutically inactive and is enzymatically hydrolysed, primarily in the blood, to the active dexamfetamine. This conversion is unaffected by gastrointestinal pH and variations in normal transit times. Lisdexamfetamine was developed with the goal of providing an extended duration of effect that is consistent throughout the day. Clinical trials have demonstrated robust clinical efficacy of lisdexamfetamine in the treatment of children, adolescents and adults with ADHD with dose-dependent improvements in the core symptoms of ADHD. Studies have further shown that the duration of action of lisdexamfetamine continues for 13 hours post-dosing in children and for 14 hours in adults. The tolerability profile of lisdexamfetamine is consistent with those of other stimulant medications, with decreased appetite, insomnia, abdominal pain and irritability among the more frequent treatment-emergent adverse events, most of which are mild to moderate in intensity and transient in nature. There are currently no parallel-group, head-to-head trial data comparing the efficacy and safety of lisdexamfetamine with other medications for ADHD. However, the available data, including a large effect size and consistent plasma concentrations throughout the day, suggest that lisdexamfetamine is a useful treatment option for patients with ADHD.     

Evaluation of risks associated with short- and long-term psychostimulant therapy for treatment of ADHD in children

Attention-deficit hyperactivity disorder (ADHD) is a common condition during childhood that is associated with significant psychosocial dysfunction. Psychostimulants are the compounds that have been most extensively studied for the treatment of ADHD in children. There is substantial scientific evidence that several methylphenidate- and amphetamine-based preparations have acute efficacy in the treatment of this condition in children. The short-term safety and tolerability of these compounds has been reasonably well-studied and the risks associated with psychostimulant therapy in the short-term are generally acceptable. However, the amount of long-term effectiveness and safety data relating to these compounds is relatively small. Data that do exist suggest that long-term treatment with psychostimulants in appropriately diagnosed patients may be associated with salutary effects as well as relatively modest risks. Until more extensive, methodologically rigorous data are available, it appears that judicious psychostimulant pharmacotherapy of ADHD in children may be justified.     

Evaluation of risks associated with short- and long-term psychostimulant therapy for treatment of ADHD in children

Attention-deficit hyperactivity disorder (ADHD) is a common condition during childhood that is associated with significant psychosocial dysfunction. Psychostimulants are the compounds that have been most extensively studied for the treatment of ADHD in children. There is substantial scientific evidence that several methylphenidate- and amphetamine-based preparations have acute efficacy in the treatment of this condition in children. The short-term safety and tolerability of these compounds has been reasonably well-studied and the risks associated with psychostimulant therapy in the short-term are generally acceptable. However, the amount of long-term effectiveness and safety data relating to these compounds is relatively small. Data that do exist suggest that long-term treatment with psychostimulants in appropriately diagnosed patients may be associated with salutary effects as well as relatively modest risks. Until more extensive, methodologically rigorous data are available, it appears that judicious psychostimulant pharmacotherapy of ADHD in children may be justified.     

Long-term use of stimulants in children with attention deficit hyperactivity disorder: safety, efficacy, and long-term outcome

The purpose of this review is to summarize existing data on the long-term safety and efficacy of stimulant treatment, and how long-term stimulant treatment of children with attention deficit hyperactivity disorder (ADHD) affects their outcome. Existing controlled studies of children with ADHD treated and untreated with stimulants, as well as long-term prospective follow-up studies, are reviewed. Children with ADHD treated with stimulants for as long as 2 years continue to benefit from the treatment, with improvements observed in ADHD symptoms, comorbid oppositional defiant disorder, and academic and social functioning, with no significant problems of tolerance or adverse effects. Long-term, prospective follow-up studies into adulthood show that stimulant treatment in childhood has slight benefits regarding social skills and self-esteem. Long-term adverse effects from stimulant treatment in childhood regarding adult height or future substance abuse have not been supported by existing studies.     

Treatment of attention deficit hyperactivity disorder in children and adolescents: safety considerations.

Despite a large body of evidence for both the validity of the diagnosis of attention deficit hyperactivity disorder (ADHD) and the efficacy of its treatment with medication, there is an equally long history of controversy. This article focuses on presenting safety information for medications approved by the US FDA for the treatment of individuals with ADHD. Stimulant medications are generally safe and effective. The common adverse effects of stimulant medications, including appetite suppression and insomnia, are usually of mild severity and manageable without stopping the medication. The more severe adverse effects such as tics or bizarre behaviours occur with low frequency and usually resolve when the medication is stopped. The possible impact on growth requires careful monitoring. Several rare but potentially severe adverse effects including sudden cardiac death and cancer following long-term treatment have been reported; however, these effects have not been adequately demonstrated to be of significant concern at this time. Atomoxetine also has a mild adverse effect profile in terms of severity and frequency although the numbers of studies and years of clinical experience is considerably less with this drug than for the stimulant medications. When the risks are juxtaposed to the clear efficacy in significantly reducing dysfunctional symptoms of ADHD, benefit-risk analyses support the continued use of these pharmacological treatments for patients with ADHD.     

Impact of Central Nervous System Stimulant Medication Use on Growth in Pediatric Populations with Attention-Deficit/Hyperactivity Disorder: A Review

Central nervous system stimulants are a commonly used first-line treatment option for attention-deficit/hyperactivity disorder (ADHD). Stimulants are generally well tolerated, with anorexia and insomnia the most common adverse effects. However, there are some concerns with long-term use of stimulants, such as potential growth delay. Historically, data regarding this long-term adverse effect have been conflicting. In this article, we review the newer data surrounding the effects of central nervous system stimulants on growth parameters in children with ADHD. We conducted a literature search of the PubMed database; only articles using ADHD criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision; and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, were included to ensure the most up-to-date review of literature. Nine articles were identified for relevance and quality and are discussed in this review, describing clinical observations of height and weight of adolescent or pediatric patients receiving stimulant medications for ADHD therapy. In summary, this review points toward potential associations between duration of treatment and higher doses of stimulants with decreased weight and body mass index. Furthermore, this review demonstrates that evidence is still conflicting regarding the relationship between stimulant use and significant height decreases. Future studies with higher quality of evidence are needed to observe this potential adverse effect of stimulants in children and adolescents.     

Psychiatric comorbidities in children with attention deficit hyperactivity disorder: implications for management

Attention deficit hyperactivity disorder (ADHD) is frequently comorbid with a variety of psychiatric disorders. These include oppositional defiant disorder and conduct disorder (CD), as well as affective, anxiety, and tic disorders. ADHD and ADHD with comorbid CD appear to be distinct subtypes; children with ADHD/CD are at higher risk of antisocial personality and substance abuse as adults. Stimulants are often effective treatments for aggressive or antisocial behavior in patients with ADHD, but mood stabilizers or atypical antipsychotics may be used to treat explosive aggressive outbursts. Response to stimulants is not affected by comorbid anxiety, but children with ADHD/anxiety disorder may show greater benefit from psychosocial interventions than those with ADHD alone. The degree of prevalence of major depressive disorder (MDD) and bipolar disorder among children with ADHD is controversial, but a subgroup of severely emotionally labile ADHD children who present serious management issues for the clinician clearly exists. Antidepressants may be used in conjunction with stimulants to treat MDD, while mood stabilizers and atypical antipsychotics are often required to treat manic symptoms or aggression. After resolution of the manic episode, stimulant treatment of the comorbid ADHD may be safely undertaken. Recent research suggests that stimulants can be safely used in children with comorbid ADHD and tic disorders, but the addition of anti-tic agents to stimulants is often necessary. Clinicians who work with patients with ADHD should be prepared to deal with a wide range of emotional and behavioral problems beyond the core symptoms of inattention and impulsivity/hyperactivity.     

Safety of stimulant treatment in attention deficit hyperactivity disorder: part II

Importance of the field: Attention deficit hyperactivity disorder (ADHD) is the most common childhood psychiatric disorder and in at least 50% of cases persists into adulthood. Treatment of ADHD with stimulants is one of the oldest and most effective pharmacological treatments in psychiatry. Yet, there continues to be controversy over the safety of stimulant medications in the treatment of ADHD.

Areas covered in this review: This paper is a continuation of an earlier paper that reviewed the safety profile of newer stimulant agents, especially in relation to special populations. This part II reviews, through essentially an organ-system approach, the various clinical concerns that have been raised over the safety of stimulant medications. This includes neuropsychiatric, cardiovascular effects on growth and development, and a number of other less common concerns.

What the reader will gain: A thorough review of safety concerns in stimulants that emphasizes clinical information, case reports, open series or controlled trials relating to stimulant use in the treatment of ADHD.

Take home message: While many safety concerns have been raised in the use of stimulants, the vast majority of treatment complications are either quickly reversible or easily manageable with appropriate clinical care. The negative consequences of untreated ADHD clearly outweigh the risks of the stimulant medicines when used in an appropriate and careful manner.     

Pharmacotherapy for parents with attention-deficit hyperactivity disorder (ADHD): impact on maternal ADHD and parenting

Given the high heritability of the disorder, attention-deficit hyperactivity disorder (ADHD) is common among parents of children with ADHD. Parental ADHD is associated with maladaptive parenting, negative parent-child interaction patterns and a diminished response to behavioural parent training. We describe our previous research demonstrating that stimulant medications for mothers with ADHD are associated with reductions in maternal ADHD symptoms. Although limited beneficial effects on self-reported parenting were also found in our study, the impact of ADHD medications on functional outcomes related to parenting and family interactions may not be sufficient for many families. Many questions remain with regard to how best to treat multiplex ADHD families in which a parent and child have ADHD. In particular, future studies are needed: (1) to evaluate how best to sequence pharmacotherapy, psychosocial treatment for adult ADHD and behavioural parenting interventions; (2) to determine the best approach to maintaining treatment effects over the long term for both parents and children; and (3) to identify individual predictors of treatment response.     

Metabolic, toxicological, and safety considerations for drugs used to treat ADHD

INTRODUCTION: Pharmacotherapy is frequently used to treat symptoms of attention-deficit/hyperactivity disorder (ADHD), the most common neurobehavioral disorder of childhood. The typically prescribed agents for ADHD have varying durations of effect and degrees of efficacy. The broad range of pharmacological treatments available allows for both single and combination therapies for achieving optimal therapeutic effects. Metabolic, toxicological, and safety information are critical for an informed evaluation of the risk/benefit considerations in prescribing practices. AREAS COVERED: This article focuses on the medications with current FDA approval for use in the treatment of ADHD in pediatric and adult populations. This review covers the stimulants (amphetamine and methylphenidate) and non-stimulants (atomoxetine, clonidine extended release, and guanfacine extended release) used to treat ADHD and presents an overview of their respective metabolic, toxicological, and safety features. A literature search and review of the relevant medications were carried out using the PubMed database up to November 2011. EXPERT OPINION: New trends in study design based on drug profiles include the use of adjuvant therapies and the inclusion of patients with comorbidities. The recent expansion of inclusion/exclusion criteria in pediatric clinical trials of ADHD allows for a more rigorous analysis of associated benefits and risks with the use of adjuvant therapy.     

Compliance with stimulants for attention-deficit/hyperactivity disorder: issues and approaches for improvement

Attention-deficit/hyperactivity disorder (ADHD) affects approximately 8-10% of school-aged children in the US and for many individuals persists into adolescence and adulthood. Both pharmacological and nonpharmacological (behavioural) therapies are used to treat individuals with ADHD. Treatment with stimulant medications, which include methylphenidate and amphetamine, typically requires multiple daily doses to maintain efficacy. The frequency of treatment, coupled with the importance of timing of doses and the long-term nature of treatment, make noncompliance a particular issue in the treatment of ADHD. Studies report noncompliance rates of 20-65% with stimulant treatment, although there are only limited published studies and these show considerable individual variation. Noncompliance can arise through inadequate supervision of those receiving medication, leading to delayed or missed doses, or through the reluctance of individuals to take medication, which is influenced by a number of factors (e.g. social attitudes, pressures or worries surrounding medication use and the inconvenience of multiple daily doses). Two approaches are likely to increase compliance with stimulant treatment: effective once-daily formulations of medication and improved treatment information. The development of effective once-daily formulations for stimulant treatments removes the need for multiple daily doses, with the associated problems of ensuring adequate treatment supervision and personal privacy. Improved provision of education and information for individuals with ADHD, as well as their families and teachers, should help them address the issues surrounding stimulant medication and allow full participation in the treatment process. Together, these strategies should improve treatment compliance for individuals with ADHD.     

Review of lisdexamfetamine dimesylate in children and adolescents with attention deficit/hyperactivity disorder

Abstract

Objective

Lisdexamfetamine dimesylate is a stimulant prodrug with low abuse and diversion potential that is used in treatment of attention deficit hyperactivity disorder (ADHD) in children, adolescents and adults. This current literature review article aims to examine safety and efficacy of LDX in children and adolescents for the treatment of ADHD based on currently available data.