Effects of stimulant drugs on academic performance in hyperactive and learning disabled children

Methylphenidate modulates motor cortical dynamics and behavior

Methylphenidate (MPH, brand: Ritalin) is a common stimulant used both medically and non-medically. Though typically prescribed for its cognitive effects, MPH also affects movement. While it is known that MPH noncompetitively blocks the reuptake of catecholamines through inhibition of dopamine and norepinephrine transporters, a critical step in exploring how it affects behavior is to understand how MPH directly affects neural activity. This would establish an electrophysiological mechanism of action for MPH. Since we now have biologically-grounded network-level hypotheses regarding how populations of motor cortical neurons plan and execute movements, there is a unique opportunity to make testable predictions regarding how systemic MPH administration - a pharmacological perturbation - might affect neural activity in motor cortex. To that end, we administered clinically-relevant doses of MPH to Rhesus monkeys as they performed an instructed-delay reaching task. Concomitantly, we measured neural activity from dorsal premotor and primary motor cortex. Consistent with our predictions, we found dose-dependent and significant effects on reaction time, trial-by-trial variability, and movement speed. We confirmed our hypotheses that changes in reaction time and variability were accompanied by previously established population-level changes in motor cortical preparatory activity and the condition-independent signal that precedes movements. We expected changes in speed to be a result of changes in the amplitude of motor cortical dynamics and/or a translation of those dynamics in activity space. Instead, our data are consistent with a mechanism whereby the neuromodulatory effect of MPH is to increase the gain and/or the signal-to-noise of motor cortical dynamics during reaching. Continued work in this domain to better understand the brain-wide electrophysiological mechanism of action of MPH and other psychoactive drugs could facilitate more targeted treatments for a host of cognitive-motor disorders.

Effects of Ritalin on Reading

A description of the nature of Ritalin, its use in education, and its effects on reading performance

Combined Stimulant and Guanfacine Administration in Attention-Deficit/Hyperactivity Disorder: A Controlled, Comparative Study

OBJECTIVE

Because models of attention-deficit/hyperactivity disorder (ADHD) therapeutics emphasize benefits of both enhanced dopaminergic and noradrenergic signaling, strategies to enhance D1 and α2A agonism may yield enhanced clinical and cognitive responses. This study tested the hypothesis that combined effects of a dopamine and noradrenergic agonist, d-methylphenidate extended-release (DMPH) with guanfacine (GUAN), an α2A receptor agonist, would be clinically superior to either monotherapy and would have equal tolerability.

METHOD

An 8-week, double-blind, 3-arm, comparative trial randomized 7- to 14-year-olds with DSM-IV ADHD to GUAN (1-3 mg/day), DMPH (5-20 mg/day), or a combination (COMB) with fixed-flexible dosing. Outcome measures were the ADHD Rating Scale IV (ADHD-RS-IV) and the Clinical Global Impression-Improvement (CGI-I) scale. Data on adverse events and safety measures were obtained.

RESULTS

A total of 207 participants were randomized and received drug. Analyses showed significant treatment group main effects for ADHD-RS-IV ADHD total (p = .0001) and inattentive symptoms (p = .0001). COMB demonstrated small but consistently greater reductions in ADHD-RS-IV Inattentive subscale scores versus monotherapies (DMPH: p = .05; f(2) = .02; and GUAN: p = .02; f(2) = .02), and was associated with a greater positive response rate by CGI-I (p = .01). No serious cardiovascular events occurred. Sedation, somnolence, lethargy, and fatigue were greater in both guanfacine groups. All treatments were well tolerated.

CONCLUSION

COMB showed consistent evidence of clinical benefits over monotherapies, possibly reflecting advantages of greater combined dopaminergic and α2A agonism. Adverse events were generally mild to moderate, and COMB treatment showed no differences in safety or tolerability.

CLINICAL TRIAL REGISTRATION INFORMATION

Single Versus Combination Medication Treatment for Children With Attention Deficit Hyperactivity Disorder (Project1); http://clinicaltrials.gov/; NCT00429273.

Pharmacotherapy for attention-deficit/hyperactivity disorder: from cells to circuits

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent disorder of childhood and adulthood, with a considerable impact on public health. There is a substantial pharmacopoeia available for safe and effective treatment of ADHD, and newly available agents diversify the treatment options. With the burgeoning scientific literature addressing the genetic, neurochemical, and neural systems basis for this condition, increasing attention is directed at establishing the neural basis for the efficacy of existing treatments. ADHD remains the only highly prevalent, nondegenerative neuropsychiatric disorder for which effective medications remediate the principal cognitive disturbances in concert with clinical efficacy. Therefore, deeper insight into the neural mechanisms of cognitive remediation may serve to advance treatment development not only in ADHD, but across a wide range of neuropsychiatric disorders in which cognitive dysfunction is a cardinal feature and a strong predictor of clinical outcome. To date, all effective medications for ADHD act on 1 or both of the major catecholamine neurotransmitter systems in the brain. These 2 systems, which arise from subcortical nuclei and use norepinephrine (NE) or dopamine (DA) as transmitters, exert strong modulatory effects on widely distributed cortical-subcortical neural circuits, with important effects on cognition, mood, and behavior, in both health and illness. The present review outlines the actions of ADHD medications from subcellular effects to effects on neural systems and cognition in ADHD patients. This is a very active area of investigation at all phases of the translational cycle, and near-term work is poised to firmly link cellular neuropharmacology to large-scale effects, and point the way toward advances in treatment.

College students with and without ADHD: comparison of self-report of medication usage, study habits, and academic achievement

OBJECTIVE

To examine the relationship between ADHD medications, study habits, and academic achievement of ADHD-diagnosed undergraduates.

METHOD

A total of 92 students with a self-reported ADHD diagnosis and a current prescription for ADHD medication were compared with 143 control students in a survey of academic performance.

RESULTS

Most ADHD students took stimulant medication and said the drugs helped them, yet believed they were worse than other students at planning and completing assignments and avoiding distractions. Although most study habits of ADHD students did not differ from controls, their high school and college GPA (grade point average), and ACT scores were significantly lower, and they withdrew from significantly more classes than did control students. Interestingly, preliminary data suggested that good study habits alone, even without stimulants, could overcome the achievement disparity of ADHD students.

CONCLUSION

As previously shown for children and adolescents, stimulant medications alone did not eliminate the academic achievement deficit of ADHD undergraduates.

What are the cognitive effects of stimulant medications? Emphasis on adults with attention-deficit/hyperactivity disorder (ADHD)

The relevant literature concerning cognitive effects of amphetamine and methylphenidate, was reviewed, with an emphasis on research conducted in adults diagnosed with attention-deficit/hyperactivity disorder. As first-line treatment for ADHD, stimulant drugs are well-known to improve attention and concentration. Yet, there is increasing evidence that (as with children and adolescents), they do not promote learning and academic achievement in adult college students with ADHD. A review of neuropsychological studies indicates that, although response latencies are reduced, performance of ADHD adults on tests of 'distractibility' and 'planning' is also not consistently improved by stimulants. Studies in non-ADHD adults suggest that stimulants do not promote acquisition of new information, might improve retention of previously acquired information, and facilitate memory consolidation, but may actually impair performance of tasks that require adaptation, flexibility and planning. It is still not clear if improvement only occurs when there is a baseline deficit. Stimulants may influence cognition by their effects on physiological arousal. Regardless, the evidence does not support the conclusion that stimulants are cognitive 'enhancers.'

Handwriting performance of children with attention deficit hyperactive disorders: a pilot study

OBJECTIVE

The aim of this study was to compare the handwriting characteristics of children diagnosed with attention deficit hyperactive disorder (ADHD), while on and off medication, as well as with a control group.

METHODS

Twelve children with ADHD and 12 control children, aged 8-10, performed a paragraph-copying task using a computerized system. The children with ADHD performed the task both while on and off medication. The handwriting product of both groups was then evaluated with the Hebrew Handwriting Evaluation tool.

CONCLUSION

Results provide evidence for poorer performance of children with ADHD in comparison to children without ADHD on most handwriting process and product measures. Children with ADHD demonstrated significantly more total time including in-air time spent in handwriting performance when off medication. The possible implications of these results regarding the future use of handwriting process and product evaluations for children with ADHD in school settings are discussed.

Motor flexibility problems as a marker for genetic susceptibility to attention-deficit/hyperactivity disorder

BACKGROUND

Since many children with attention-deficit/hyperactivity disorder (ADHD) have fine visuomotor problems that are already evident at a young age, motor dysfunctioning is investigated in family-genetic perspective. We hypothesized that if fine motor problems may be a marker for genetic susceptibility to ADHD, nonaffected siblings of ADHD probands would experience motor problems similar to those of their ADHD siblings.

METHODS

Twenty-five carefully phenotyped ADHD probands with a family history of ADHD, their nonaffected siblings (n = 25), and 48 normal control subjects (aged 6 to 17) completed a motor fluency task and a motor flexibility task. The motor fluency task involved completion of a familiar, automatized trajectory, whereas the motor flexibility task required continuous adjustment of movement to complete an unpredictable random trajectory.

RESULTS

On the motor fluency task, the performance of the nonaffected children was significantly better than that of the ADHD probands; strikingly, on the motor flexibility task, they performed as well as their ADHD siblings.

CONCLUSIONS

Nonaffected siblings experience complex motor problems similar to their ADHD siblings but only in nonautomatized movements that require controlled processing. The results suggest that higher-order controlled motor deficits in ADHD may be associated with genetic susceptibility for ADHD.

Relationship between motor proficiency, attention, impulse, and activity in children with ADHD

The aim of this study was to investigate the relationship between motor performance, attention deficit, impulsiveness, and hyperactivity in children with attention-deficit--hyperactivity disorder (ADHD). Participants were 42 school-aged children with ADHD (36 males, 6 females; mean age 8 years 2 months, SD 1 year 2 months; range 6 years to 11 years), and 42 age- and sex-matched children without ADHD (mean age 8 years 3 months, SD 1 year 1 month; range 6 years to 11 years). Motor abilities were assessed with the Bruininks-Oseretsky Test of Motor Proficiency. Attention and impulse control were measured with the Gordon Diagnostic System, and assessment of activity level was based on two Activity Level Rating Scales that were completed by parents and teachers. Analysis by t-test revealed a significant difference between children with and without ADHD in fine and gross motor skills, impulse control, and attention. Stepwise regression indicated that attention, impulse control, and parent ratings of activity level were the three best predictors of gross motor skills for children with ADHD, accounting for 55.9% of the variance. Attention and impulse control were the two best predictors of fine motor skills, accounting for 45.7% of the variance. Attention and impulse control were consistently found to be important predictors of both fine and gross motor skills in children with ADHD. However, the fact that activity level was a predictor for gross motor proficiency but not for fine motor tasks suggests that different behavioral processes are involved in fine and gross motor performance to different extents.

Methylphenidate effects on EEG, behavior, and performance in boys with ADHD

The psychophysiologic and behavioral effects of methylphenidate were assessed in boys with attention deficit hyperactivity disorder between the ages of 9 and 11 years. The effects of methylphenidate on the EEG during baseline and cognitive tasks were evaluated using spectral analysis. Both subjective (rating scales) and objective (continuous performance) measures were administered and analyzed in conjunction with the electrophysiologic data. Although methylphenidate induced regional changes in the EEG under certain task-specific conditions, it had no global effects. Behavioral and performance measures improved with methylphenidate.

Differential effects of methylphenidate and self-reinforcement on attention-deficit hyperactivity disorder

Six boys aged 9 to 12 years attended a tutoring class focusing on reading for 30 minutes each morning. The investigators employed a modified Latin-square design in which each child began with a 5-day baseline phase followed by six 10-day treatment phases that used drug placebo, noncontingent reinforcers, 0.3 mg/kg methylphenidate, 0.7 mg/kg methylphenidate, and self-reinforcement in various combinations. Amount of academic performance was the major measure of outcome and the target behavior of self-reinforcement. Drug placebo and noncontingent reinforcers had no systematic impact. Methylphenidate had differential effects across the recorded behaviors. Self-reinforcement improved the target behavior; the mean effect size for self-reinforcement was 2.66. The combined effects of methylphenidate and self-reinforcement on academic performance were greater than either of the treatments given alone (mean effect size = 2.89).

Classroom academic performance: improvement with both methylphenidate and dextroamphetamine in ADHD boys

Daily academic classroom performance was recorded in a day hospital school using a commonly employed reading and math series as part of an 11-week double-blind, placebo controlled, crossover comparison of dextroamphetamine (d-AMPH) and methylphenidate (MPH) in 33 hyperactive boys. Students attempted more math and reading tasks while on either active drug. The percent correct and the number of attempted problems of the reading series improved with both drugs while the percent correct for the math series occurred with d-AMPH only. No dose-response relationship was found for either stimulant. Moderate, transient adverse effects were common for both drugs.

The effects of a multimodal intervention with attention-deficit hyperactivity disorder children: a 9-month follow-up

Using a double-blind, placebo design, we evaluated 96 attention-deficit hyperactivity disordered children for the effects of methylphenidate alone and in combination with behavioral parent training plus child self-control instruction. Seventy one of the children completed the treatment protocol. As reported previously, main effects were found for medication at posttest; however, there was no evidence of additive effects. Nine months after the termination of the behavioral interventions and the withdrawal of the stimulant medication, we found limited support for the hypothesis that the combined conditions would produce greater maintenance of treatment gains than would medication alone.

Additive effects of psychostimulants, parent training, and self-control therapy with ADHD children

Utilizing a double-blind, placebo design, the effects of a high (0.8 mg/kg) and a low (0.4 mg/kg) dose of methylphenidate alone and in combination with behavioral parent training plus child self-control instruction were evaluated with 96 attention deficit hyperactivity disorder children. No evidence of the superiority of the combined conditions relative to medication alone was found. Some limited support was found for the hypothesis that the effects of a high dose of psychostimulant medication could be achieved by combining the low dose with a behavioral intervention. The importance of the latter finding is highlighted by the fact that both the benefits and untoward effects of the psychostimulants appear to increase with the dose.

Stimulant medication therapy in the treatment of children with attention deficit hyperactivity disorder

Despite the tremendous research advances that have increased our knowledge regarding the pharmacodynamics, clinical pharmacology, pharmacokinetics, and adverse effects of stimulant medications in the treatment of children with ADHD, our knowledge is yet incomplete. Perhaps the most central unresolved issue concerns our understanding of the pathogenesis, pathophysiology, and diagnosis of ADHD. This review has touched briefly on the controversy and confusion surrounding this issue. Although our understanding of the use of stimulant medications in this disorder is similarly incomplete, a review of the literature does allow certain conclusions to be made that are helpful to the practitioner. 1. Stimulant medications are an effective treatment modality for most children with ADHD. Short-term efficacy is well documented, and long-term outcome may be improved when stimulants are used with other therapeutic strategies. Stimulants in and of themselves are not a panacea. 2. It is impossible to predict which children will have a favorable response to stimulant medications and which children may have a placebo response. The use of individual single-blind medication trials is a practical solution to this problem and should be considered for all children who are candidates for stimulant therapy as a means for preventing overuse or inappropriate use of these medications. 3. The precise mechanism of action of stimulants is not yet completely understood, but stimulants appear to exert their therapeutic effects through their influence on multiple neurotransmitters in the catecholamine, dopamine, norepinephrine axis in the central nervous system. 4. The three major stimulants--methylphenidate, dextroamphetamine, and pemoline--appear to be equally efficacious, although methylphenidate has emerged as the most commonly used and most studied drug. Because of its potential for causing liver toxicity, pemoline has remained a second-line medication. 5. The three major stimulants appear to have somewhat different mechanisms of action so that failure of a patient to respond to one medication does not mean that he or she will not respond to another. 6. The recommended starting doses for the stimulants are 0.3 mg per kg of methylphenidate, 0.15 mg per kg of dextroamphetamine, and 37.5 mg of pemoline. There is a great deal of individual variability in dose response, so doses must be titrated for optimal effects in each child. Sustained release preparations are much more expensive than regular preparations and may be less effective. 7. There is no evidence that stimulants have any effect on ultimate adult height. 8. Although relatively uncommon, motor tics have been observed in children on stimulants, and all children on stimulants need to be carefully monitored for the development of tics. (ABSTRACT TRUNCATED AT 250 WORDS)

Cognitive training in academically deficient ADDH boys receiving stimulant medication

This study evaluated the effectiveness of a 16-week intensive cognitive training program in stimulant-treated, academically deficient ADDH boys. Cognitive training focused exclusively on academic skills and tasks, and included attack strategy training as well as self-monitoring and self-reinforcement of problem-solving behaviors and response accuracy. Control groups included remedial tutoring plus medication, and medication alone. Despite the scope of the program, the results provided no support for the notion that academically based cognitive training ameliorates the performance and achievement of academically deficient ADDH youngsters. Further, this intervention did not enhance self-esteem or attributional perceptions of academic functioning. There was poor agreement between teacher ratings of academic competence and test score changes. The lack of concordance between measures, and the scarcity of academically deficient ADDH children are discussed.

The effects of methylphenidate on levels of processing and laterality in children with attention deficit disorder

Effects of stimulant medication (methylphenidate) on levels (feature, name, semantic) of word processing by the left and right hemisphere were assessed in 31 attention-deficit-disordered children. In a double-blind procedure, same-different decisions were made to tachistoscopically presented word pairs under medication and placebo. Analysis of manual response times failed to show any negative effects of medication. Feature decisions were faster than name decisions, which were faster than semantic decisions. Methylphenidate induced a right visual field advantage (left hemisphere) for the name decision, which was interpreted as a normalization effect. The results suggest that (1) methylphenidate may selectively improve the phonological level of word processing and (2) methylphenidate's favorable therapeutic effect is produced through inhibition of excessive right hemisphere activity in response to task demands that engage the left hemisphere.

Psychophysiological effects of methylphenidate (Ritalin)

The nature and psychophysiological effects of methylphenidate whose metabolism, pharmacokinetics, and effects on human behavior are not well known are the focus of this review. Methylphenidate treatment of attention deficit disorder with hyperactivity is presented summarily.

Attention deficit disorder: current perspectives

This review focuses on selected issues in the rapidly proliferating scientific literature on attention deficit disorder (ADD). It encompasses a brief overview of ADD, including a review of the historical trends, causation, and a description of the clinical characteristics. Critical issues fundamental to understanding of ADD are addressed next. Evidence is presented to suggest that there are several groups of children with ADD who are currently under-identified and therefore, underserved (girls with ADD; ADD without hyperactivity). The concept is introduced of uncomplicated ADD and ADD-Plus (ADD-P), a term used to designate ADD associated with other complicating features such as conduct disorder. Specific methodologic issues and their relationship to the under-identification of these groups of children follows. This discussion encompasses the reasons for diagnostic imprecision and inconsistency, emphasizing the problem of selective referral patterns and how it results in an inaccurate portrait of ADD. We then present new approaches to the definition and diagnosis of ADD based on empiric studies designed to circumvent some of these problems. We conclude with a summary of the implications of these findings, and recommendations for public policy in ADD, particularly the need to recognize that ADD may occur even in the most intellectually gifted individuals and even in students in select colleges. Often these children with the highest potential are penalized most, not because of conceptual limitations or because they do not understand, but because educators often fail to recognize the symptom complex. Many of these children are succeeding through intelligence and great effort, but many more could succeed with proper identification.

Clinical management of children with hyperactivity. A shift in diagnostic and therapeutic emphasis

Children who have attention deficit disorder with (or without) hyperactivity are handicapped by their inability to concentrate and control their impulsivity, especially while in school. Specific performance disabilities prevent them from demonstrating, especially through written schoolwork, what they have learned. Parents and teachers are likely to mistake these children's symptoms for willful misbehavior or lack of motivation, which leads to misunderstandings and even mistreatment. The critical issue in the management of a child with hyperactivity is to effectively treat the key problems of inattention and impulsivity rather than the hyperactivity per se. A nonintensive long-term approach combining stimulant therapy and a cooperative liaison among the physician, child, family, and teachers is recommended.

Short term effects of methylphenidate on the cognitive, learning and academic performance of children with attention deficit disorder in the laboratory and the classroom

Sixteen children meeting diagnostic criteria for Attention Deficit Disorder with Hyperactivity (ADD-H) were tested on methylphenidate (0.3 mg/kg) and placebo on cognitive, learning, academic and behavioral measures in a double-blind study. Assessments were carried out in the laboratory and in the children's regular classrooms. Results indicate methylphenidate-induced improvements on a majority of the measures. Drug-induced changes reflected increased output, accuracy and efficiency and improved learning acquisition. There was also evidence of increased effort and self-correcting behaviours. It is argued that reviewers have underestimated the potential of stimulants to improve the performance of ADD-H children on academic, learning and cognitive tasks.

Methylphenidate and cognitive therapy: a comparison of treatment approaches with hyperactive boys

This study of hyperactive boys evaluated the effects of three modes of treatment in relation to an untreated group. The treatments were administered over a 3-month period and included cognitive training, stimulant drug therapy (methylphenidate), and the two treatments combined. A follow-up assessment was conducted approximately 3 months after contact between the training staff and the child had ceased. Analyses of attentional deployment and cognitive style measures, tests of academic achievement, and behavioral ratings showed that only those children in the two medication treatment conditions demonstrated improvement in attentional deployment and behavioral ratings. In the cognitive therapy condition, there were changes only on measures of attentional deployment. The data did not provide evidence indicating that the combined medication and cognitive therapy condition was any more effective than that condition involving medication alone. Discussion provides future guidelines for evaluation of the relative effectiveness of stimulant drug therapy and other psychological treatment modalities.

Hyperactivity and the attention deficit disorders: expanding frontiers

This article explores some of the pivotal research in the understanding and treatment of hyperactivity, overviewing the research milestones as well as the vexing questions that remain. Focus is placed upon the social worlds of hyperactive children and upon the overlap between hyperactive and aggressive behavior patterns. This is followed by an extensive look at the effects of stimulants upon these children and the needs for (and promise of) nonpharmacologic treatment strategies as adjuncts or alternatives to medication.

Diagnosis and management of attention deficit disorder: a pediatric perspective

Recent progress in the nosology of neuropsychiatric disorders in general, and attention deficit disorder in particular, have produced parallel advances in our understanding of the etiology of these disorders, enhanced their accurate recognition, and clarified appropriate management strategies. This article provides a detailed overview of these advances.