Methylphenidate in children with ADHD with or without learning disability

Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD)

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed and treated psychiatric disorders in childhood. Typically, children and adolescents with ADHD find it difficult to pay attention and they are hyperactive and impulsive. Methylphenidate is the psychostimulant most often prescribed, but the evidence on benefits and harms is uncertain. This is an update of our comprehensive systematic review on benefits and harms published in 2015.

OBJECTIVES

To assess the beneficial and harmful effects of methylphenidate for children and adolescents with ADHD.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, three other databases and two trials registers up to March 2022. In addition, we checked reference lists and requested published and unpublished data from manufacturers of methylphenidate.

SELECTION CRITERIA

We included all randomised clinical trials (RCTs) comparing methylphenidate versus placebo or no intervention in children and adolescents aged 18 years and younger with a diagnosis of ADHD. The search was not limited by publication year or language, but trial inclusion required that 75% or more of participants had a normal intellectual quotient (IQ > 70). We assessed two primary outcomes, ADHD symptoms and serious adverse events, and three secondary outcomes, adverse events considered non-serious, general behaviour, and quality of life.

DATA COLLECTION AND ANALYSIS

Two review authors independently conducted data extraction and risk of bias assessment for each trial. Six review authors including two review authors from the original publication participated in the update in 2022. We used standard Cochrane methodological procedures. Data from parallel-group trials and first-period data from cross-over trials formed the basis of our primary analyses. We undertook separate analyses using end-of-last period data from cross-over trials. We used Trial Sequential Analyses (TSA) to control for type I (5%) and type II (20%) errors, and we assessed and downgraded evidence according to the GRADE approach.

MAIN RESULTS

We included 212 trials (16,302 participants randomised); 55 parallel-group trials (8104 participants randomised), and 156 cross-over trials (8033 participants randomised) as well as one trial with a parallel phase (114 participants randomised) and a cross-over phase (165 participants randomised). The mean age of participants was 9.8 years ranging from 3 to 18 years (two trials from 3 to 21 years). The male-female ratio was 3:1. Most trials were carried out in high-income countries, and 86/212 included trials (41%) were funded or partly funded by the pharmaceutical industry. Methylphenidate treatment duration ranged from 1 to 425 days, with a mean duration of 28.8 days. Trials compared methylphenidate with placebo (200 trials) and with no intervention (12 trials). Only 165/212 trials included usable data on one or more outcomes from 14,271 participants. Of the 212 trials, we assessed 191 at high risk of bias and 21 at low risk of bias. If, however, deblinding of methylphenidate due to typical adverse events is considered, then all 212 trials were at high risk of bias.

PRIMARY OUTCOMES

methylphenidate versus placebo or no intervention may improve teacher-rated ADHD symptoms (standardised mean difference (SMD) -0.74, 95% confidence interval (CI) -0.88 to -0.61; I² = 38%; 21 trials; 1728 participants; very low-certainty evidence). This corresponds to a mean difference (MD) of -10.58 (95% CI -12.58 to -8.72) on the ADHD Rating Scale (ADHD-RS; range 0 to 72 points). The minimal clinically relevant difference is considered to be a change of 6.6 points on the ADHD-RS. Methylphenidate may not affect serious adverse events (risk ratio (RR) 0.80, 95% CI 0.39 to 1.67; I² = 0%; 26 trials, 3673 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 0.91 (CI 0.31 to 2.68).

SECONDARY OUTCOMES

methylphenidate may cause more adverse events considered non-serious versus placebo or no intervention (RR 1.23, 95% CI 1.11 to 1.37; I² = 72%; 35 trials 5342 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 1.22 (CI 1.08 to 1.43). Methylphenidate may improve teacher-rated general behaviour versus placebo (SMD -0.62, 95% CI -0.91 to -0.33; I² = 68%; 7 trials 792 participants; very low-certainty evidence), but may not affect quality of life (SMD 0.40, 95% CI -0.03 to 0.83; I² = 81%; 4 trials, 608 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

The majority of our conclusions from the 2015 version of this review still apply. Our updated meta-analyses suggest that methylphenidate versus placebo or no-intervention may improve teacher-rated ADHD symptoms and general behaviour in children and adolescents with ADHD. There may be no effects on serious adverse events and quality of life. Methylphenidate may be associated with an increased risk of adverse events considered non-serious, such as sleep problems and decreased appetite. However, the certainty of the evidence for all outcomes is very low and therefore the true magnitude of effects remain unclear. Due to the frequency of non-serious adverse events associated with methylphenidate, the blinding of participants and outcome assessors is particularly challenging. To accommodate this challenge, an active placebo should be sought and utilised. It may be difficult to find such a drug, but identifying a substance that could mimic the easily recognised adverse effects of methylphenidate would avert the unblinding that detrimentally affects current randomised trials. Future systematic reviews should investigate the subgroups of patients with ADHD that may benefit most and least from methylphenidate. This could be done with individual participant data to investigate predictors and modifiers like age, comorbidity, and ADHD subtypes.

Are Reading Interventions Effective for At-Risk Readers with ADHD? A Meta-Analysis

OBJECTIVE

Utilizing a multi-level meta-analytic approach, this review is the first to systematically quantify the efficacy of reading interventions for school-aged children with ADHD and identify potential factors that may increase the success of reading-related interventions for these children.

METHOD

18 studies (15 peer-reviewed articles, 3 dissertations) published from 1986 to 2020 (N = 564) were meta-analyzed.

RESULTS

Findings revealed reading interventions are highly effective for improving reading skills based on both study-developed/curriculum-based measures (g = 1.91) and standardized/norm-referenced achievement tests (g = 1.11) in high-quality studies of children with rigorously-diagnosed ADHD. Reading interventions that include at least 30 hours of intervention targeting decoding/phonemic awareness meet all benchmarks to be considered a Level 1 (Well-Established) Evidence-Based Practice with Strong Research Support for children with ADHD based on clinical and special education criteria.

CONCLUSIONS

Our findings collectively indicate that reading interventions should be the first-line treatment for reading difficulties among at-risk readers with ADHD.

Society for Developmental and Behavioral Pediatrics Clinical Practice Guideline for the Assessment and Treatment of Children and Adolescents with Complex Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder and is associated with an array of coexisting conditions that complicate diagnostic assessment and treatment. ADHD and its coexisting conditions may impact function across multiple settings (home, school, peers, community), placing the affected child or adolescent at risk for adverse health and psychosocial outcomes in adulthood. Current practice guidelines focus on the treatment of ADHD in the primary care setting. The Society for Developmental and Behavioral Pediatrics has developed this practice guideline to facilitate integrated, interprofessional assessment and treatment of children and adolescents with "complex ADHD" defined by age (<4 years or presentation at age >12 years), presence of coexisting conditions, moderate to severe functional impairment, diagnostic uncertainty, or inadequate response to treatment.

Handwriting in children with Attention Deficient Hyperactive Disorder: role of graphology

Background

Handwriting difficulties are common in children with attention deficient hyperactive disorder (ADHD). The aim of our study was to find distinctive characteristics of handwriting in children with ADHD by using graphology to analyze physical characteristics and patterns, and to evaluate whether graphological analysis is an effective ADHD diagnostic tool for clinicians.

Method

The cohort included 49 children aged 13–18 years attending a tertiary neurology and epilepsy center in 2016–2017; 22 had a previous DSM-IV/V diagnosis of ADHD. The children were asked to write a 10–12-line story in Hebrew on a blank sheet of paper with a blue pen over a 20-min period. The samples were analyzed by a licensed graphologist blinded to the clinical details of the children against a predetermined handwriting profile of individuals with ADHD. Each ADHD characteristic identified in each sample was accorded 1 point, up to a total of 15 points. Patients with a graphology score of 9–15 were considered to have ADHD.

Results

There were 21 boys (43%) and 28 girls (57%) in the cohort; 15 boys (71.4%) and 7 girls (25%) had a DSM-IV/V diagnosis of ADHD. The mean graphology score was significantly higher in the children who had a DSM-IV/V diagnosis of ADHD than in the children who did not (9.61 + 3.49 vs. 5.79 + 4.01, p = 0.002, respectfully). Using a score of 9 as the cutoff, in the girls, graphology had a specificity of 80% (95% CI 59.2–92.8) and a of sensitivity 71.4% for predicting ADHD. Corresponding values in the boys were 75.0 and 76.2%.

Conclusion

The handwriting of children with ADHD has specific characteristics. Graphology may serve as a clinically useful tool in the diagnosis of ADHD.

The Effects of ADHD Treatment and Reading Intervention on the Fluency and Comprehension of Children with ADHD and Word Reading Difficulties: A Randomized Clinical Trial

Many students with reading difficulties and disabilities (RD) also have Attention Deficit/Hyperactivity Disorder (ADHD). This randomized clinical trial compared the effects of ADHD treatment alone (medication, parent training), intensive reading intervention alone, and their combination on the reading fluency and comprehension of students with both disorders. Students with ADHD and RD were randomly assigned to receive (a) Reading Intervention only (n=74), (b) ADHD Treatment only (n=78), or (c) simultaneous Combined ADHD and RD Treatment (n=70). For phonemic decoding fluency, the Reading Intervention group and the Combined Treatment group both had significantly better outcomes than the ADHD Treatment group, but did not differ from one another. For passage comprehension, the ADHD Treatment group had significantly better outcomes than the Reading Intervention group, while the other groups did not differ from one another. ADHD treatment may support passage comprehension in this population, while fluent decoding is best supported through intensive reading intervention.

Does methylphenidate improve academic performance? A systematic review and meta-analysis

Academic improvement is amongst the most common treatment targets when prescribing stimulants to children with ADHD. Previous reviews on stimulant-related academic improvements are inconclusive and focus on task engagement. Recent literature suggests outcome-domain-specific medication effects that are larger for productivity than for accuracy. The aims of this study are quantifying methylphenidate effects on academic productivity and accuracy for math, reading, spelling; exploring the mediating or moderating effects of symptom improvements, demographic-, design- and disorder-related variables. PubMed, EMBASE, ERIC and PsycINFO were searched for articles reporting methylphenidate effects on academic productivity and accuracy. Thirty-four studies met entry criteria. Methylphenidate improved math productivity (7.8% increase, p < .001); math accuracy (3.0% increase, p = .001); increased reading speed (SMD .47, p < .001) but not reading accuracy. None of the mediators or moderators tested affected methylphenidate efficacy. Academic improvements were small compared to symptom improvements; qualitative changes limited to math. Clinicians should take this discrepancy into account when prescribing medication for ADHD.

The effectiveness of methylphenidate in the management of Attention Deficit Hyperactivity Disorder (ADHD) in people with intellectual disabilities: A systematic review

BACKGROUND

The effectiveness of psychostimulants, primarily methylphenidate (MPH), in the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in the general population of typically growing children and adolescents is well established through many Randomised Controlled Trials (RCTs).

AIMS AND METHODS

We carried out a systematic review of all the RCTs in people with intellectual disabilities (ID) that assessed effectiveness of MPH on the core ADHD symptoms.

OUTCOMES AND RESULTS

We included 15 papers from 13 studies that were all on children and adolescents with ID (315 participants were on MPH and placebo respectively), 12 of which used a cross over design, and one used a parallel design. On average around 40-50% responded to MPH in the ID group whereas around 70-80% response rate is reported among the non-ID children. Because of the heterogeneity of the outcome data it was not possible to carry out a meta-analysis. Significant adverse events included sleep difficulties and poor appetite along with weight loss and also irritability, social withdrawal and increased motor activities including tic.

CONCLUSIONS AND IMPLEMENTATION

On the basis of the poor quality evidence that is available, it seems that MPH may be effective in some but not all children and adolescents with ID and ADHD.

Using ADHD Medications to Treat Coexisting ADHD and Reading Disorders: A Systematic Review

Attention-deficit/hyperactivity disorder (ADHD), the most common pediatric neurobehavioral disorder, frequently presents with coexisting reading disorders (RDs). Despite this, it is unclear whether medication improves symptoms and function in children with comorbid ADHD and RD. We present a systematic review of studies investigating the effects of ADHD medications on ADHD symptoms, academic outcomes, and neuropsychological measures in this important group.

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.

Short-Term Effects of Methylphenidate on Math Productivity in Children With Attention-Deficit/Hyperactivity Disorder are Mediated by Symptom Improvements: Evidence From a Placebo-Controlled Trial

BACKGROUND

Although numerous studies report positive effects of methylphenidate on academic performance, the mechanism behind these improvements remains unclear. This study investigates the effects of methylphenidate on academic performance in children with attention-deficit/hyperactivity disorder (ADHD) and the mediating and moderating influence of ADHD severity, academic performance, and ADHD symptom improvement.

METHODS

Sixty-three children with ADHD participated in a double-blind placebo-controlled crossover study comparing the effects of long-acting methylphenidate and placebo. Dependent variables were math, reading, and spelling performance. The ADHD group performance was compared with a group of 67 typically developing children.

RESULTS

Methylphenidate improved math productivity and accuracy in children with ADHD. The effect of methylphenidate on math productivity was partly explained by parent-rated symptom improvement, with greater efficacy for children showing more symptom improvement. Further, children showing below-average math performance while on placebo profited more from methylphenidate than children showing above-average math performance.

CONCLUSIONS

The results from this study indicate positive effects of methylphenidate on academic performance, although these were limited to math abilities. In light of these results, expectations of parents, teachers, and treating physicians about the immediate effects of methylphenidate on academic improvement should be tempered. Moreover, our results implicate that positive effects of methylphenidate on math performance are in part due directly to effects on math ability and in part due to reductions in ADHD symptoms.

Comparing treatments for children with ADHD and word reading difficulties: A randomized clinical trial

OBJECTIVE

This trial compared attention-deficit/hyperactivity disorder (ADHD) treatment alone, intensive reading intervention alone, and their combination for children with ADHD and word reading difficulties and disabilities (RD).

METHOD

Children (n = 216; predominantly African American males) in Grades 2-5 with ADHD and word reading/decoding deficits were randomized to ADHD treatment (medication + parent training), reading treatment (reading instruction), or combined ADHD + reading treatment. Outcomes were parent and teacher ADHD ratings and measures of word reading/decoding. Analyses utilized a mixed models covariate-adjusted gain score approach with posttest regressed onto pretest.

RESULTS

Inattention and hyperactivity/impulsivity outcomes were significantly better in the ADHD (parent Hedges's g = .87/.75; teacher g = .67/.50) and combined (parent g = 1.06/.95; teacher g = .36/41) treatment groups than reading treatment alone; the ADHD and Combined groups did not differ significantly (parent g = .19/.20; teacher g = .31/.09). Word reading and decoding outcomes were significantly better in the reading (word reading g = .23; decoding g = .39) and combined (word reading g = .32; decoding g = .39) treatment groups than ADHD treatment alone; reading and combined groups did not differ (word reading g = .09; decoding g = .00). Significant group differences were maintained at the 3- to 5-month follow-up on all outcomes except word reading.

CONCLUSIONS

Children with ADHD and RD benefit from specific treatment of each disorder. ADHD treatment is associated with more improvement in ADHD symptoms than RD treatment, and reading instruction is associated with better word reading and decoding outcomes than ADHD treatment. The additive value of combining treatments was not significant within disorder, but the combination allows treating both disorders simultaneously. (PsycINFO Database Record

Effect of Atomoxetine Treatment on Reading and Phonological Skills in Children with Dyslexia or Attention-Deficit/Hyperactivity Disorder and Comorbid Dyslexia in a Randomized, Placebo-Controlled Trial

OBJECTIVES

Evaluated the effects of atomoxetine on the reading abilities of children with dyslexia only or attention-deficit/hyperactivity disorder (ADHD) and comorbid dyslexia.

METHODS

Children aged 10-16 years (N = 209) met Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria for dyslexia only (n = 58), ADHD and comorbid dyslexia (n = 124), or ADHD only (n = 27) and were of normal intelligence. Patients were treated with atomoxetine (1.0-1.4 mg/kg/day) or placebo in a 16-week, randomized, placebo-controlled, double-blind trial. The dyslexia-only and ADHD and comorbid dyslexia groups were randomized 1:1; the ADHD-only group received atomoxetine in a blinded manner. Reading abilities were measured with the Woodcock Johnson III (WJIII), Comprehensive Test of Phonological Processing (CTOPP), Gray Oral Reading Tests-4, and Test of Word Reading Efficiency.

RESULTS

Atomoxetine-treated dyslexia-only patients compared with placebo patients had significantly greater improvement (p < 0.02) with moderate to approaching high effect sizes (ES) on WJIII Word Attack (ES = 0.72), Basic Reading Skills (ES = 0.48), and Reading Vocabulary (ES = 0.73). In the atomoxetine-treated ADHD and comorbid dyslexia group, improvement on the CTOPP Elision measure (ES = 0.50) was significantly greater compared with placebo (p < 0.02). Total, inattentive, and hyperactive/impulsive ADHD symptom reductions were significant in the atomoxetine-treated ADHD and comorbid dyslexia group compared with placebo, and from baseline in the ADHD-only group (p ≤ 0.02). ADHD symptom improvements in the ADHD and comorbid dyslexia group were not correlated with improvements in reading.

CONCLUSIONS

Atomoxetine treatment improved reading scores in patients with dyslexia only and ADHD and comorbid dyslexia. Improvements for patients with dyslexia only were in critical components of reading, including decoding and reading vocabulary. For patients with ADHD and comorbid dyslexia, improvements in reading scores were distinct from improvement in ADHD inattention symptoms alone. These data represent the first report of improvements in reading measures following pharmacotherapy treatment in patients with dyslexia only evaluated in a randomized, double-blind trial.

An Open-label, Self-control, Prospective Study on Cognitive Function, Academic Performance, and Tolerability of Osmotic-release Oral System Methylphenidate in Children with Attention-deficit Hyperactivity Disorder

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is the most common mental and behavioral disorder in school-aged children. This study evaluated the effect of osmotic-release oral system (OROS) methylphenidate (MPH) on cognitive function and academic performance of Chinese school-aged children with ADHD.

METHODS

This 12-week, prospective, multicenter, open-label, self-controlled study enrolled 153 Chinese school-aged children with ADHD and 41 non-ADHD children. Children with ADHD were treated with once-daily OROS-MPH (18 mg, 36 mg, or 54 mg). The primary endpoints were Inattention/Overactivity (I/O) with Aggression Conners Behavior Rating Scale (IOWA) and Digit Span Test at week 12 compared with baseline. Secondary endpoints included opposition/defiant (O/D) subscale of IOWA, Clinical Global Impression (CGI), Coding Test, Stroop Color-word Test, Wisconsin Card Sorting Test (WCST), academic performance on teacher-rated school examinations, and safety at week 12 compared with baseline. Both non-ADHD and ADHD children received the same frequency of cognitive operational test to avoid the possible bias caused by training.

RESULTS

A total of 128 patients were evaluated with cognitive assessments. The OROS-MPH treatment significantly improved IOWA Conners I/O subscale scores at week 12 (3.8 ± 2.3) versus baseline (10.0 ± 2.4; P < 0.0001). Digit Span Test scores improved significantly (P < 0.0001) with a high remission rate (81.1%) at week 12 versus baseline. A significant (P < 0.0001) improvement was observed in O/D subscale of IOWA, CGI, Coding Test, Stroop Color-word Test, WCST, and academic performance at week 12 versus baseline. Very few practice-related improvements were noticed in the non-ADHD group at week 12 compared with baseline. No serious adverse events and deaths were reported during the study.

CONCLUSIONS

The OROS-MPH treatment effectively controlled symptoms of ADHD and significantly improved academic performance and cognitive function of Chinese school-aged children with ADHD. The treatment was found to be safe and generally well-tolerated over 12 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01933880; http://clinicaltrials.gov/ct2/show/NCT01933880?term=CONCERTAATT4099&rank=1.

Combined Modality Intervention for ADHD With Comorbid Reading Disorders: A Proof of Concept Study

To evaluate the relative efficacy of two reading programs with and without adjunctive stimulant medication for children with attention-deficit/hyperactivity disorder and comorbid reading disorder (ADHD+RD). Sixty-five children (7-11 years in age) were assigned randomly to one of three intensive remedial academic programs (phonologically or strategy-based reading instruction, or general academic strategy and social skills training) in combination with either immediate-release methylphenidate or placebo. Multiple-blind procedures were used for medication/placebo, given twice daily. Children received 35 hours of instruction in 10 weeks, taught by a trained teacher in a separate school classroom, in small matched groups of 2 to 3. Children's behavior and reading abilities were assessed before and after intervention. Stimulant medication produced expected beneficial effects on hyperactive/impulsive behavioral symptoms (reported by classroom teachers) but none on reading. Children receiving a reading program showed greater gains than controls on multiple standardized measures of reading and related skills (regardless of medication status). Small sample sizes precluded interpretation of possible potentiating effects of stimulant medication on reading skills taught in particular reading programs. Intensive reading instruction, regardless of treatment with stimulant medication, may be efficacious in improving reading problems in children with ADHD+RD and warrants further investigation in a large-scale study.

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.

Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD)

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed and treated psychiatric disorders in childhood. Typically, children with ADHD find it difficult to pay attention, they are hyperactive and impulsive.Methylphenidate is the drug most often prescribed to treat children and adolescents with ADHD but, despite its widespread use, this is the first comprehensive systematic review of its benefits and harms.

OBJECTIVES

To assess the beneficial and harmful effects of methylphenidate for children and adolescents with ADHD.

SEARCH METHODS

In February 2015 we searched six databases (CENTRAL, Ovid MEDLINE, EMBASE, CINAHL, PsycINFO, Conference Proceedings Citations Index), and two trials registers. We checked for additional trials in the reference lists of relevant reviews and included trials. We contacted the pharmaceutical companies that manufacture methylphenidate to request published and unpublished data.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing methylphenidate versus placebo or no intervention in children and adolescents aged 18 years and younger with a diagnosis of ADHD. At least 75% of participants needed to have an intellectual quotient of at least 70 (i.e. normal intellectual functioning). Outcomes assessed included ADHD symptoms, serious adverse events, non-serious adverse events, general behaviour and quality of life.

DATA COLLECTION AND ANALYSIS

Seventeen review authors participated in data extraction and risk of bias assessment, and two review authors independently performed all tasks. We used standard methodological procedures expected within Cochrane. Data from parallel-group trials and first period data from cross-over trials formed the basis of our primary analyses; separate analyses were undertaken using post-cross-over data from cross-over trials. We used Trial Sequential Analyses to control for type I (5%) and type II (20%) errors, and we assessed and downgraded evidence according to the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach for high risk of bias, imprecision, indirectness, heterogeneity and publication bias.

MAIN RESULTS

The studies.We included 38 parallel-group trials (5111 participants randomised) and 147 cross-over trials (7134 participants randomised). Participants included individuals of both sexes, at a boys-to-girls ratio of 5:1, and participants' ages ranged from 3 to 18 years across most studies (in two studies ages ranged from 3 to 21 years). The average age across all studies was 9.7 years. Most participants were from high-income countries.The duration of methylphenidate treatment ranged from 1 to 425 days, with an average duration of 75 days. Methylphenidate was compared to placebo (175 trials) or no intervention (10 trials). Risk of Bias.All 185 trials were assessed to be at high risk of bias. Primary outcomes. Methylphenidate may improve teacher-rated ADHD symptoms (standardised mean difference (SMD) -0.77, 95% confidence interval (CI) -0.90 to -0.64; 19 trials, 1698 participants; very low-quality evidence). This corresponds to a mean difference (MD) of -9.6 points (95% CI -13.75 to -6.38) on the ADHD Rating Scale (ADHD-RS; range 0 to 72 points; DuPaul 1991a). A change of 6.6 points on the ADHD-RS is considered clinically to represent the minimal relevant difference. There was no evidence that methylphenidate was associated with an increase in serious (e.g. life threatening) adverse events (risk ratio (RR) 0.98, 95% CI 0.44 to 2.22; 9 trials, 1532 participants; very low-quality evidence). The Trial Sequential Analysis-adjusted intervention effect was RR 0.91 (CI 0.02 to 33.2).

SECONDARY OUTCOMES

Among those prescribed methylphenidate, 526 per 1000 (range 448 to 615) experienced non-serious adverse events, compared with 408 per 1000 in the control group. This equates to a 29% increase in the overall risk of any non-serious adverse events (RR 1.29, 95% CI 1.10 to 1.51; 21 trials, 3132 participants; very low-quality evidence). The Trial Sequential Analysis-adjusted intervention effect was RR 1.29 (CI 1.06 to 1.56). The most common non-serious adverse events were sleep problems and decreased appetite. Children in the methylphenidate group were at 60% greater risk for trouble sleeping/sleep problems (RR 1.60, 95% CI 1.15 to 2.23; 13 trials, 2416 participants), and 266% greater risk for decreased appetite (RR 3.66, 95% CI 2.56 to 5.23; 16 trials, 2962 participants) than children in the control group.Teacher-rated general behaviour seemed to improve with methylphenidate (SMD -0.87, 95% CI -1.04 to -0.71; 5 trials, 668 participants; very low-quality evidence).A change of seven points on the Child Health Questionnaire (CHQ; range 0 to 100 points; Landgraf 1998) has been deemed a minimal clinically relevant difference. The change reported in a meta-analysis of three trials corresponds to a MD of 8.0 points (95% CI 5.49 to 10.46) on the CHQ, which suggests that methylphenidate may improve parent-reported quality of life (SMD 0.61, 95% CI 0.42 to 0.80; 3 trials, 514 participants; very low-quality evidence).

AUTHORS' CONCLUSIONS

The results of meta-analyses suggest that methylphenidate may improve teacher-reported ADHD symptoms, teacher-reported general behaviour, and parent-reported quality of life among children and adolescents diagnosed with ADHD. However, the low quality of the underpinning evidence means that we cannot be certain of the magnitude of the effects. Within the short follow-up periods typical of the included trials, there is some evidence that methylphenidate is associated with increased risk of non-serious adverse events, such as sleep problems and decreased appetite, but no evidence that it increases risk of serious adverse events.Better designed trials are needed to assess the benefits of methylphenidate. Given the frequency of non-serious adverse events associated with methylphenidate, the particular difficulties for blinding of participants and outcome assessors point to the advantage of large, 'nocebo tablet' controlled trials. These use a placebo-like substance that causes adverse events in the control arm that are comparable to those associated with methylphenidate. However, for ethical reasons, such trials should first be conducted with adults, who can give their informed consent.Future trials should publish depersonalised individual participant data and report all outcomes, including adverse events. This will enable researchers conducting systematic reviews to assess differences between intervention effects according to age, sex, comorbidity, type of ADHD and dose. Finally, the findings highlight the urgent need for large RCTs of non-pharmacological treatments.

Executive and attentional contributions to Theory of Mind deficit in attention deficit/hyperactivity disorder (ADHD)

Attention deficit/hyperactivity disorder (ADHD) in children has been associated with attentional and executive problems, but also with socioemotional difficulties possibly associated with deficits in Theory of Mind (ToM). Socioemotional problems in ADHD are associated with more negative prognoses, notably interpersonal, educational problems, and an increased risk of developing other psychiatric disorders that emphasize the need to clarify the nature of their ToM deficits. In this study, we hypothesized that ToM dysfunction in children with ADHD is largely attributable to their attentional and/or executive deficits. Thirty-one children with ADHD (8-12 years, IQ > 85) and 31 typically developing (TD) children were assessed using executive functions (inhibition, planning, and flexibility) and attentional tasks, as well as two advanced ToM tasks (Reading the Mind in the Eyes and Faux Pas) involving different levels of executive control. Children with ADHD performed more poorly than TD children in attentional, executive function, and ToM tasks. Linear regression analyses conducted in the ADHD group indicated that inhibition scores predicted performance on the "Faux Pas" task the best, while attention scores were the best for predicting performance on the Reading the Mind in the Eyes task. When controlled for inhibition and attentional variables, ToM performance in children with ADHD was actually similar to TD children. Contrarily, controlling for ToM scores did not normalize performance for inhibition and attentional tasks in children with ADHD. This unidirectional relationship suggests that deficits in the EF and attentional domains are responsible for ToM deficits in ADHD, which therefore may contribute to their socioemotional difficulties.