Discontinuation of pharmacological treatment of children and adolescents with attention deficit hyperactivity disorder: meta-analysis of 63 studies enrolling 11,788 patients

Randomized, Double-Blind, Placebo-Controlled Trial on the Efficacy, Safety and Tolerability of Modified-Release Methylphenidate (MPH-MR) in Chinese Children and Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD)

BACKGROUND AND OBJECTIVES

The efficacy and safety of modified-release methylphenidate (MPH-MR) in the treatment of attention-deficit/hyperactivity disorder (ADHD) have been shown in both pediatric and adult Caucasian patients. The objective of this study was to assess the efficacy and safety of MPH-MR in Chinese children and adolescents with ADHD.

METHODS

MICCA was a randomized, double-blind, placebo-controlled trial conducted at 19 sites in China from September 2018 to July 2021. The study enrolled children and adolescents aged 6 to < 18 years with a primary diagnosis of ADHD according to the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5). Patients were randomized 1:1 to once-daily MPH-MR (10-60 mg) or placebo. The study included an up-titration phase of up to 5 weeks and a dose maintenance phase of 4 weeks. The primary efficacy endpoint was the change in the ADHD Rating Scale-IV (ADHD-RS-IV) total score from baseline to the end of the maintenance phase (EoM). Secondary endpoints included the change from baseline to EoM in Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) total score, and Clinical Global Impression-Improvement (CGI-I) scores at EoM. Safety assessments included treatment-emergent adverse events (TEAEs) and vital signs.

RESULTS

A total of 221 patients were randomized (MPH-MR: n = 110; placebo: n = 111). The change in the ADHD-RS-IV total score from baseline to EoM was significantly greater for MPH-MR versus placebo, with a least squares (LS) mean (95% confidence interval [CI]) treatment difference of - 4.6 (- 6.92, - 2.30) (p < 0.001). The mean (95% CI) treatment difference for the WFIRS-P total score change from baseline to EoM also significantly favored MPH-MR over placebo (- 6.46 [- 10.57, - 2.34]; p = 0.002). The CGI-I score at EoM was significantly lower in the MPH-MR group compared to the placebo group (2.2 vs 2.5; p = 0.002). Treatment-emergent adverse events were reported for 74 (67.3%) patients in the MPH-MR group and 55 (49.1%) patients in the placebo group. Most TEAEs were mild to moderate in severity. The most common TEAEs for MPH-MR were decreased appetite, nausea and upper respiratory tract infection. Treatment-emergent adverse events leading to study drug discontinuation/study withdrawal were reported in 4 (3.6%) patients in the MPH-MR group and 1 (0.9%) patient in the placebo group. No clinically relevant changes in vital signs were observed during the study.

CONCLUSIONS

Modified-release methylphenidate was superior to placebo in improving ADHD symptoms and functioning in Chinese pediatric patients with ADHD. Modified-release methylphenidate had a good safety and tolerability profile. Trial Registration http://www.chinadrugtrials.org.cn/ Identifier: CTR20180056 (registered on 21 May 2018).

Stimulant Treatment and Potential Adverse Outcomes in Pediatric Populations With Bipolar Disorder: A Systematic Review of the Literature

OBJECTIVE

To explore outcomes of stimulant treatment for ADHD in pediatric populations with particular attention to bipolar disorder (BPD).

METHOD

We conducted a literature search of PubMed articles published prior to August 25, 2022 that focused on BPD, mania, and psychosis prior to, or as result of, stimulant treatment. We excluded studies: (1) unrelated to stimulants, (2) general stimulant research, (3) articles older than 40 years, (4) study protocols, or (5) case reports.

RESULTS

A total of 11 articles met all inclusion/exclusion criteria. Some reports found stimulant treatment safe and well-tolerated in children with comorbid BPD and ADHD. Others found evidence of treatment-emergent mania (TEM), discontinuation, and other adverse events with stimulant treatment.

CONCLUSION

Poor outcomes associated with stimulant treatment in pediatric populations with BPD necessitate work to identify patients at risk of serious stimulant-related adverse events. Our results were limited by automated search filters and a pediatric, primarily male sample.

The Effects of Theta/Beta-based Neurofeedback Training on Attention in Children with Attention Deficit Hyperactivity Disorder: A Systematic Review and Meta-analysis

Neurofeedback training is a common treatment option for attention deficit hyperactivity disorder (ADHD). Given theta/beta-based neurofeedback (T/B NF) training targets at the electrophysiological characteristics of children with ADHD, benefits for attention may be expected. PsycINFO, PubMed, ScienceDirect, Scopus, and Web of Science were searched through December 31, 2020. Studies were evaluated with Risk of Bias tools. Within-group effects based on Pre- and Post-treatment comparisons of the Intervention Group, and Between-group effects based on the between-group differences from Pre-treatment to Post-treatment were calculated. Nineteen studies met selection criteria for systematic review, 12 of them were included in meta-analysis. Within-group effects were medium at Post-treatment and large at Follow-up. Between-group analyses revealed that T/B NF was superior to waitlist control and physical activities, but not stimulant medication. Results showed that T/B NF has benefits for attention in children with ADHD, however, cautions should be taken when interpreting the findings.

A systematic meta-review of systematic reviews on attention deficit hyperactivity disorder

BACKGROUND

There are now hundreds of systematic reviews on attention deficit hyperactivity disorder (ADHD) of variable quality. To help navigate this literature, we have reviewed systematic reviews on any topic on ADHD.

METHODS

We searched MEDLINE, PubMed, PsycINFO, Cochrane Library, and Web of Science and performed quality assessment according to the Joanna Briggs Institute Manual for Evidence Synthesis. A total of 231 systematic reviews and meta-analyses met the eligibility criteria.

RESULTS

The prevalence of ADHD was 7.2% for children and adolescents and 2.5% for adults, though with major uncertainty due to methodological variation in the existing literature. There is evidence for both biological and social risk factors for ADHD, but this evidence is mostly correlational rather than causal due to confounding and reverse causality. There is strong evidence for the efficacy of pharmacological treatment on symptom reduction in the short-term, particularly for stimulants. However, there is limited evidence for the efficacy of pharmacotherapy in mitigating adverse life trajectories such as educational attainment, employment, substance abuse, injuries, suicides, crime, and comorbid mental and somatic conditions. Pharmacotherapy is linked with side effects like disturbed sleep, reduced appetite, and increased blood pressure, but less is known about potential adverse effects after long-term use. Evidence of the efficacy of nonpharmacological treatments is mixed.

CONCLUSIONS

Despite hundreds of systematic reviews on ADHD, key questions are still unanswered. Evidence gaps remain as to a more accurate prevalence of ADHD, whether documented risk factors are causal, the efficacy of nonpharmacological treatments on any outcomes, and pharmacotherapy in mitigating the adverse outcomes associated with ADHD.

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

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

Bacterial gut microbiome differences in adults with ADHD and in children with ADHD on psychostimulant medication

Recent evidence suggests that there is a link between neurodevelopmental disorders, such as attention deficit hyperactivity disorder (ADHD), and the gut microbiome. However, most studies to date have had low sample sizes, have not investigated the impact of psychostimulant medication, and have not adjusted for potential confounders, including body mass index, stool consistency and diet. To this end, we conducted the largest, to our knowledge, fecal shotgun metagenomic sequencing study in ADHD, with 147 well-characterized adult and child patients. For a subset of individuals, plasma levels of inflammatory markers and short-chain fatty acids were also measured. In adult ADHD patients (n=84), compared to controls (n=52), we found a significant difference in beta diversity both regarding bacterial strains (taxonomic) and bacterial genes (functional). In children with ADHD (n=63), we found that those on psychostimulant medication (n=33 on medication vs. n=30 not on medication) had (i) significantly different taxonomic beta diversity, (ii) lower functional and taxonomic evenness, (iii) lower abundance of the strain Bacteroides stercoris CL09T03C01 and bacterial genes encoding an enzyme in vitamin B₁₂ synthesis, and (iv) higher plasma levels of vascular inflammatory markers sICAM-1 and sVCAM-1. Our study continues to support a role for the gut microbiome in neurodevelopmental disorders and provides additional insights into the effects of psychostimulant medication. However, additional studies are needed to replicate these findings and examine causal relationships with the disorder.

APPRAISE-RS: Automated, updated, participatory, and personalized treatment recommender systems based on GRADE methodology

Purpose

Clinical practice guidelines (CPGs) have become fundamental tools for evidence-based medicine (EBM). However, CPG suffer from several limitations, including obsolescence, lack of applicability to many patients, and limited patient participation. This paper presents APPRAISE-RS, which is a methodology that we developed to overcome these limitations by automating, extending, and iterating the methodology that is most commonly used for building CPGs: the GRADE methodology.

Method

APPRAISE-RS relies on updated information from clinical studies and adapts and automates the GRADE methodology to generate treatment recommendations. APPRAISE-RS provides personalized recommendations because they are based on the patient's individual characteristics. Moreover, both patients and clinicians express their personal preferences for treatment outcomes which are considered when making the recommendation (participatory). Rule-based system approaches are used to manage heuristic knowledge.

Results

APPRAISE-RS has been implemented for attention deficit hyperactivity disorder (ADHD) and tested experimentally on 28 simulated patients. The resulting recommender system (APPRAISE-RS/TDApp) shows a higher degree of treatment personalization and patient participation than CPGs, while recommending the most frequent interventions in the largest body of evidence in the literature (EBM). Moreover, a comparison of the results with four blinded psychiatrist prescriptions supports the validation of the proposal.

Conclusions

APPRAISE-RS is a valid methodology to build recommender systems that manage updated, personalized and participatory recommendations, which, in the case of ADHD includes at least one intervention that is identical or very similar to other drugs prescribed by psychiatrists.

The Efficacy of Physical Activity for Children with Attention Deficit Hyperactivity Disorder: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

This systematic review and meta-analysis assesses the efficacy of regular, moderate to vigorous physical activity (MVPA) for attention deficit hyperactivity disorder (ADHD) in children and adolescents in randomized controlled trials (RCTs).

METHODS

RCTs including children and adolescents with clinically diagnosed ADHD, implementing regular MVPA, and assessing ADHD core-symptoms on a valid rating scale post-intervention (primary outcome) were included. Outcomes were pooled through random-effects meta-analysis. Prospero registration: CRD42019142166.

RESULTS

MVPA had a small effect on total ADHD core symptoms (n = 11; g = -0.33; 95% CI [-0.63; -0.02]; p = .037).

CONCLUSIONS

MVPA could serve as an alternative treatment for ADHD. New RCTs are necessary to increase the understanding of the effect regarding frequency, intensity, type of MVPA interventions, and differential effects on age groups.

New Drugs to Treat ADHD: Opportunities and Challenges in Research and Development

Since the landmark MTA (Multimodal Treatment of ADHD) trial unequivocally demonstrated the efficacy of methylphenidate, catecholaminergic drugs, especially stimulants, have been the therapeutic mainstay in treatment of Attention-Deficit Hyperactivity Disorder (ADHD). We review the new drugs which have entered the ADHD formulary. The lessons learned from drug-candidates that have succeeded in clinical trials together with those that have not have also been considered. What emerges confirms and consolidates the hypothesis that clinically effective ADHD drugs indirectly or directly increase catecholaminergic neurotransmission in the prefrontal cortex (PFC). Attempts to enhance catecholaminergic signalling through modulatory neurotransmitter systems or cognitive-enhancing drugs have all failed. New drugs approved for ADHD are catecholaminergic reuptake inhibitors and releasing agents, or selective noradrenaline reuptake inhibitors. Triple reuptake inhibitors with preferential effects on dopamine have not been successful. The substantial number of failures probably accounts for a continued focus on developing novel catecholaminergic and noradrenergic drugs, and a dearth of drug-candidates with novel mechanisms entering clinical development. However, substantial improvements in ADHD pharmacotherapy have been achieved by the almost exclusive use of once-daily medications and prodrugs, e.g. lisdexamfetamine and Azstarys^®, which improve compliance, deliver greater efficacy and reduce risks for diversion and abuse.

Multimodal Interventions Are More Effective in Improving Core Symptoms in Children With ADHD

Objective: To investigate the effect of sensory integration training combined with EEG biofeedback on core symptoms in children with ADHD. Methods: Fifty-two children with attention-deficit, hyperactive-impulsive and combined ADHD were selected. They were randomly divided into control group, sensory integration training group, EEG biofeedback group, and sensory integration training + EEG biofeedback group, and after 4 months of intervention, concentration time and impulsive- hyperactivity and hyperactivity index scores on the PSQ scale were assessed. Results: Compared with that before the intervention, the attention time was significantly increased (P < 0.01), and the impulsive-hyperactivity and hyperactivity index scores were significantly decreased (P < 0.05, P < 0.01). After the intervention, the attention time was significantly higher than that of the control group (P < 0.05, P < 0.01), the attention time of the multimodal intervention group was significantly higher than that of the single intervention group (P < 0.01), and the impulsive-hyperactivity and hyperactivity index scores were significantly lower than those of the single intervention group (P < 0.05). Conclusion: Multimodal intervention can significantly improve the concentration level of children with ADHD, and significantly improve the behavioral symptoms of impulsive-hyperactivity and hyperactivity. Multimodal interventions were more effective than single interventions in improving core symptoms in children with ADHD. The results of this study provide a reference for related research and practical application.

Placebo Response and Its Predictors in Attention Deficit Hyperactivity Disorder: A Meta-Analysis and Comparison of Meta-Regression and MetaForest

BACKGROUND

High placebo response in attention deficit hyperactivity disorder (ADHD) can reduce medication-placebo differences, jeopardizing the development of new medicines. This research aims to (1) determine placebo response in ADHD, (2) compare the accuracy of meta-regression and MetaForest in predicting placebo response, and (3) determine the covariates associated with placebo response.

METHODS

A systematic review with meta-analysis of randomized, placebo-controlled clinical trial investigating pharmacological interventions for ADHD was performed. Placebo response was defined as the change from baseline in ADHD symptom severity assessed according to the 18-item, clinician-rated, DSM-based rating scale. The effect of study design-, intervention-, and patient-related covariates in predicting placebo response was studied by means of meta-regression and MetaForest.

RESULTS

Ninety-four studies including 6614 patients randomized to placebo were analyzed. Overall, placebo response was -8.9 points, representing a 23.1% reduction in the severity of ADHD symptoms. Cross-validated accuracy metrics for meta-regression were R2 = 0.0012 and root mean squared error = 3.3219 for meta-regression and 0.0382 and 3.2599 for MetaForest. Placebo response among ADHD patients increased by 63% between 2001 and 2020 and was larger in the United States than in other regions of the world.

CONCLUSIONS

Strong placebo response was found in ADHD patients. Both meta-regression and MetaForest showed poor performance in predicting placebo response. ADHD symptom improvement with placebo has markedly increased over the last 2 decades and is greater in the United States than the rest of the world.

Relationship Between Treatment Duration and Efficacy of Pharmacological Treatment for ADHD: A Meta-Analysis and Meta-Regression of 87 Randomized Controlled Clinical Trials

Objective: To determine the relationship between treatment duration and the efficacy of pharmacological treatment for reducing ADHD symptoms. Method: We conducted a systematic review of randomized, double-blind, placebo-controlled clinical trials investigating the efficacy of pharmacological interventions in patients with ADHD. The last bibliographic search was performed in April 15, 2019. The effect of treatment duration on efficacy was studied using meta-regression. Results: A total of 87 studies lasting from 3 to 28 weeks were included. Pharmacological treatment improved ADHD symptom severity by -7.35 points. Treatment duration did not moderate the efficacy of pharmacological treatment. Consistent results were found for psychostimulant drugs, methylphenidate, amphetamine derivatives, atomoxetine, and α2-agonists. A negative correlation was found between baseline ADHD severity efficacy (Coefficient = -.250, p = .013). Conclusion: The efficacy of pharmacological treatment for ADHD remains stable over time. A greater efficacy in more severe patients is suggested.

Overdiagnosis of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents: A Systematic Scoping Review

Importance

Reported increases in attention-deficit/hyperactivity disorder (ADHD) diagnoses are accompanied by growing debate about the underlying factors. Although overdiagnosis is often suggested, no comprehensive evaluation of evidence for or against overdiagnosis has ever been undertaken and is urgently needed to enable evidence-based, patient-centered diagnosis and treatment of ADHD in contemporary health services.

Objective

To systematically identify, appraise, and synthesize the evidence on overdiagnosis of ADHD in children and adolescents using a published 5-question framework for detecting overdiagnosis in noncancer conditions.

Evidence Review

This systematic scoping review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews and Joanna Briggs Methodology, including the PRISMA-ScR Checklist. MEDLINE, Embase, PsychINFO, and the Cochrane Library databases were searched for studies published in English between January 1, 1979, and August 21, 2020. Studies of children and adolescents (aged ≤18 years) with ADHD that focused on overdiagnosis plus studies that could be mapped to 1 or more framework question were included. Two researchers independently reviewed all abstracts and full-text articles, and all included studies were assessed for quality.

Findings

Of the 12 267 potentially relevant studies retrieved, 334 (2.7%) were included. Of the 334 studies, 61 (18.3%) were secondary and 273 (81.7%) were primary research articles. Substantial evidence of a reservoir of ADHD was found in 104 studies, providing a potential for diagnoses to increase (question 1). Evidence that actual ADHD diagnosis had increased was found in 45 studies (question 2). Twenty-five studies showed that these additional cases may be on the milder end of the ADHD spectrum (question 3), and 83 studies showed that pharmacological treatment of ADHD was increasing (question 4). A total of 151 studies reported on outcomes of diagnosis and pharmacological treatment (question 5). However, only 5 studies evaluated the critical issue of benefits and harms among the additional, milder cases. These studies supported a hypothesis of diminishing returns in which the harms may outweigh the benefits for youths with milder symptoms.

Conclusions and Relevance

This review found evidence of ADHD overdiagnosis and overtreatment in children and adolescents. Evidence gaps remain and future research is needed, in particular research on the long-term benefits and harms of diagnosing and treating ADHD in youths with milder symptoms; therefore, practitioners should be mindful of these knowledge gaps, especially when identifying these individuals and to ensure safe and equitable practice and policy.

Pharmacotherapy of attention-deficit hyperactivity disorder: common quandaries, dilemmas and challenges

Multiple studies have shown that pharmacologic treatments for attention-deficit hyperactivity disorder (ADHD), especially stimulants, are generally effective. There is yet a paucity of empirical data, however, for some common clinical conditions overlooked in the ADHD treatment guidelines. Some examples include: in cases of first line treatment failure, it is unclear whether switching from one type of stimulant to another is beneficial. In cases of comorbid ADHD and severe aggressive/disruptive behavior in children, it is unclear whether the best first-line treatment is stimulants or atypical antipsychotics like risperidone. In cases of ADHD with comorbid anxiety disorders, there is no clear evidence regarding optimal treatment. The objectives of this article are to review these issues and propose possible answers for such clinical dilemmas.

Treatment strategies for ADHD: an evidence-based guide to select optimal treatment

Attention-deficit/hyperactivity disorder (ADHD) is a common and impairing disorder affecting children, adolescents, and adults. Several treatment strategies are available that can successfully ameliorate symptoms, ranging from pharmacological to dietary interventions. Due to the increasing range of available options, an informed selection or prioritization of treatments is becoming harder for clinicians. This review aims to provide an evidence-based appraisal of the literature on ADHD treatment, supplemented by expert opinion on plausibility. We outline proposed mechanisms of action of established pharmacologic and non-pharmacologic treatments, and we review targets of novel treatments. The most relevant evidence supporting efficacy and safety of each treatment strategy is discussed. We review the individualized features of the patient that should guide the selection of treatments in a shared decision-making continuum. We provide guidance for optimizing initiation of treatment and follow-up of patients in clinical settings.

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.

Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a childhood-onset disorder characterised by inattention, hyperactivity, and impulsivity. ADHD can persist into adulthood and can affects individuals' social and occupational functioning, as well as their quality of life and health. ADHD is frequently associated with other mental disorders such as substance use disorders and anxiety and affective disorders. Amphetamines are used to treat adults with ADHD, but uncertainties about their efficacy and safety remain.

OBJECTIVES

To examine the efficacy and safety of amphetamines for adults with ADHD.

SEARCH METHODS

In August 2017, we searched CENTRAL, MEDLINE, Embase, PsycINFO, 10 other databases, and two trials registers, and we ran citation searches for included studies. We also contacted the corresponding authors of all included studies, other experts in the field, and the pharmaceutical company, Shire, and we searched the reference lists of retrieved studies and reviews for other published, unpublished, or ongoing studies. For each included study, we performed a citation search in Web of Science to identify any later studies that may have cited it.

SELECTION CRITERIA

We searched for randomised controlled trials comparing the efficacy of amphetamines (at any dose) for ADHD in adults aged 18 years and over against placebo or an active intervention.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data from each included study. We used the standardised mean difference (SMD) and the risk ratio (RR) to assess continuous and dichotomous outcomes, respectively. We conducted a stratified analysis to determine the influence of moderating variables. We assessed trials for risk of bias and drew a funnel plot to investigate the possibility of publication bias. We rated the quality of the evidence using the GRADE approach, which yielded high, moderate, low, or very low quality ratings based on evaluation of within-trial risk of bias, directness of evidence, heterogeneity of data; precision of effect estimates, and risk of publication bias.

MAIN RESULTS

We included 19 studies that investigated three types of amphetamines: dexamphetamine (10.2 mg/d to 21.8 mg/d), lisdexamfetamine (30 mg/d to 70 mg/d), and mixed amphetamine salts (MAS; 12.5 mg/d to 80 mg/d). These studies enrolled 2521 participants; most were middle-aged (35.3 years), Caucasian males (57.2%), with a combined type of ADHD (78.8%). Eighteen studies were conducted in the USA, and one study was conducted in both Canada and the USA. Ten were multi-site studies. All studies were placebo-controlled, and three also included an active comparator: guanfacine, modafinil, or paroxetine. Most studies had short-term follow-up and a mean study length of 5.3 weeks.We found no studies that had low risk of bias in all domains of the Cochrane 'Risk of bias' tool, mainly because amphetamines have powerful subjective effects that may reveal the assigned treatment, but also because we noted attrition bias, and because we could not rule out the possibility of a carry-over effect in studies that used a cross-over design.Sixteen studies were funded by the pharmaceutical industry, one study was publicly funded, and two studies did not report their funding sources.Amphetamines versus placeboSeverity of ADHD symptoms: we found low- to very low-quality evidence suggesting that amphetamines reduced the severity of ADHD symptoms as rated by clinicians (SMD -0.90, 95% confidence interval (CI) -1.04 to -0.75; 13 studies, 2028 participants) and patients (SMD -0.51, 95% CI -0.75 to -0.28; six studies, 120 participants).Retention: overall, we found low-quality evidence suggesting that amphetamines did not improve retention in treatment (risk ratio (RR) 1.06, 95% CI 0.99 to 1.13; 17 studies, 2323 participants).Adverse events: we found that amphetamines were associated with an increased proportion of patients who withdrew because of adverse events (RR 2.69, 95% CI 1.63 to 4.45; 17 studies, 2409 participants).Type of amphetamine: we found differences between amphetamines for the severity of ADHD symptoms as rated by clinicians. Both lisdexamfetamine (SMD -1.06, 95% CI -1.26 to -0.85; seven studies, 896 participants; low-quality evidence) and MAS (SMD -0.80, 95% CI -0.93 to -0.66; five studies, 1083 participants; low-quality evidence) reduced the severity of ADHD symptoms. In contrast, we found no evidence to suggest that dexamphetamine reduced the severity of ADHD symptoms (SMD -0.24, 95% CI -0.80 to 0.32; one study, 49 participants; very low-quality evidence). In addition, all amphetamines were efficacious in reducing the severity of ADHD symptoms as rated by patients (dexamphetamine: SMD -0.77, 95% CI -1.14 to -0.40; two studies, 35 participants; low-quality evidence; lisdexamfetamine: SMD -0.33, 95% CI -0.65 to -0.01; three studies, 67 participants; low-quality evidence; MAS: SMD -0.45, 95% CI -1.02 to 0.12; one study, 18 participants; very low-quality evidence).Dose at study completion: different doses of amphetamines did not appear to be associated with differences in efficacy.Type of drug-release formulation: we investigated immediate- and sustained-release formulations but found no differences between them for any outcome.Amphetamines versus other drugsWe found no evidence that amphetamines improved ADHD symptom severity compared to other drug interventions.

AUTHORS' CONCLUSIONS

Amphetamines improved the severity of ADHD symptoms, as assessed by clinicians or patients, in the short term but did not improve retention to treatment. Amphetamines were associated with higher attrition due to adverse events. The short duration of studies coupled with their restrictive inclusion criteria limits the external validity of these findings. Furthermore, none of the included studies had an overall low risk of bias. Overall, the evidence generated by this review is of low or very low quality.

Predictors of discontinuation, efficacy, and safety of memantine treatment for Alzheimer's disease: meta-analysis and meta-regression of 18 randomized clinical trials involving 5004 patients

BACKGROUND

The risk-benefit relationship of memantine treatment for Alzheimer's disease (AD) remains unclear. In addition, variability between the results of clinical trials has been observed. The aim of this study was to investigate the risk-benefit relationship of memantine treatment in patients with AD and to determine the predictor effect of patient, intervention, and study design related covariates.

METHODS

A systematic review and meta-analysis of double-blind, placebo controlled clinical trials was performed. Primary outcomes were all-cause discontinuation, discontinuation due to adverse events (AE) and efficacy on cognitive function. Odds ratio (OR) and standard mean difference (SMD) with 95% confidence intervals were calculated. Meta-regression was conducted to identify related covariates. Cochrane Collaboration tool was used to evaluate the risk of bias of included trials.

RESULTS

Eighteen studies involving 5004 patients were included. No differences between memantine and placebo were found for all-cause treatment discontinuation (OR=0.97 [0.82, 1.14]) and discontinuation due to AE (OR=1.18 [0.91, 1.53]). Memantine showed small improvement on cognitive function (SMD=0.15 [0.08, 0.22]). Baseline functional ability was positively associated with all-cause treatment discontinuation and discontinuation due to AE.

CONCLUSIONS

Our study suggests that memantine has a very small efficacy on AD symptomatology and its safety profile is similar to that of placebo. No evidence of treatment discontinuation improvement with memantine is found, indicating a dubious risk-benefit relationship. No intervention characteristic or subgroup of patients clearly shows a significantly better risk-benefit relationship.

PROSPERO REGISTRATION

CRD42014015696 .