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

Change in striatal functional connectivity networks across 2 years due to stimulant exposure in childhood ADHD: results from the ABCD sample

Widely prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), stimulants (e.g., methylphenidate) have been studied for their chronic effects on the brain in prospective designs controlling dosage and adherence. While controlled approaches are essential, they do not approximate real-world stimulant exposure contexts where medication interruptions, dosage non-compliance, and polypharmacy are common. Brain changes in real-world conditions are largely unexplored. To fill this gap, we capitalized on the observational design of the Adolescent Brain Cognitive Development (ABCD) study to examine effects of stimulants on large-scale bilateral cortical networks' resting-state functional connectivity (rs-FC) with 6 striatal regions (left and right caudate, putamen, and nucleus accumbens) across two years in children with ADHD. Bayesian hierarchical regressions revealed associations between stimulant exposure and change in rs-FC of multiple striatal-cortical networks, affiliated with executive and visuo-motor control, which were not driven by general psychotropic medication. Of these connections, three were selective to stimulants versus stimulant naive: reduced rs-FC between caudate and frontoparietal network, and between putamen and frontoparietal and visual networks. Comparison with typically developing children in the ABCD sample revealed stronger rs-FC reduction in stimulant-exposed children for putamen and frontoparietal and visual networks, suggesting a normalizing effect of stimulants. 14% of stimulant-exposed children demonstrated reliable reduction in ADHD symptoms, and were distinguished by stronger rs-FC reduction between right putamen and visual network. Thus, stimulant exposure for a two-year period under real-world conditions modulated striatal-cortical functional networks broadly, had a normalizing effect on a subset of networks, and was associated with potential therapeutic effects involving visual attentional control.

Change in Striatal Functional Connectivity Networks Across Two Years Due to Stimulant Exposure in Childhood ADHD: Results from the ABCD Sample

Widely prescribed for Attention-Deficit/Hyperactivity Disorder (ADHD), stimulants (e.g., methylphenidate) have been studied for their chronic effects on the brain in prospective designs controlling dosage and adherence. While controlled approaches are essential, they do not approximate real-world stimulant exposure contexts where medication interruptions, dosage non-compliance, and polypharmacy are common. Brain changes in real-world conditions are largely unexplored. To fill this gap, we capitalized on the observational design of the Adolescent Brain Cognitive Development (ABCD) study to examine effects of stimulants on large-scale bilateral cortical networks' resting-state functional connectivity (rs-FC) with 6 striatal regions (left and right caudate, putamen, and nucleus accumbens) across two years in children with ADHD. Bayesian hierarchical regressions revealed associations between stimulant exposure and change in rs-FC of multiple striatal-cortical networks, affiliated with executive and visuo-motor control, which were not driven by general psychotropic medication. Of these connections, three were selective to stimulants versus stimulant naive: reduced rs-FC between caudate and frontoparietal network, and between putamen and frontoparietal and visual networks. Comparison with typically developing children in the ABCD sample revealed stronger rs-FC reduction in stimulant-exposed children for putamen and frontoparietal and visual networks, suggesting a normalizing effect of stimulants. 14% of stimulant-exposed children demonstrated reliable reduction in ADHD symptoms, and were distinguished by stronger rs-FC reduction between right putamen and visual network. Thus, stimulant exposure for a two-year period under real-world conditions modulated striatal-cortical functional networks broadly, had a normalizing effect on a subset of networks, and was associated with potential therapeutic effects involving visual attentional control.

Effects of methylphenidate on executive functioning in children and adolescents with ADHD after long-term use: a randomized, placebo-controlled discontinuation study

BACKGROUND

Methylphenidate may improve executive functioning in children with attention-deficit/hyperactivity disorder (ADHD). However, it is unclear if there are still acute effects of methylphenidate on executive functioning after long-term use.

METHODS

In a randomized double-blind, placebo-controlled discontinuation study, 94 children and adolescents (ages 8-18 years) who used methylphenidate beyond two years were either assigned to seven weeks of continued treatment with 36 or 54 mg of extended-release methylphenidate or to gradual withdrawal over three weeks to placebo for four weeks. Performance on neuropsychological tasks, measuring working memory, response inhibition, attentional flexibility and psychomotor speed was compared between both groups using mixed models for repeated measures. Additionally, we investigated within the discontinuation group if a deterioration on the investigator-rated Clinical Global Impressions Improvement scale after withdrawing to placebo was related to a worse performance on the neuropsychological tasks. This study was registered in the Netherlands Trial Register (www. Trialregister.nl) with identifier 5252.

RESULTS

After withdrawal of methylphenidate, the discontinuation group made more errors on working memory (β = -1.62, SD = 0.56, t = -2.88, p = .01, Cohen's f2 = .14), independent from reaction time compared to baseline, in contrast to the continuation group. We did not find differences in changes in response inhibition, attentional flexibility and psychomotor speed between the two groups. Also, there were no significant differences in task measures between the participants who deteriorated clinically and those who did not.

CONCLUSIONS

Our study shows that methylphenidate has a beneficial effect on working memory after two years of use. Future studies should explore whether cognitive outcomes may aid clinical decision-making on the continued use of methylphenidate, given dissociation between cognitive and behavioural effects of stimulant medication.

Continued Benefits of Methylphenidate in ADHD After 2 Years in Clinical Practice: A Randomized Placebo-Controlled Discontinuation Study

OBJECTIVE

The benefits of long-term use of methylphenidate treatment in children and adolescents with attention deficit hyperactivity disorder (ADHD), as frequently prescribed in clinical practice, are unclear. The authors investigated whether methylphenidate remains beneficial after 2 years of use.

METHODS

Ninety-four children and adolescents (ages 8-18 years) who had been treated in regular care with methylphenidate for more than 2 years were randomly assigned to double-blind continuation of treatment for 7 weeks (36 or 54 mg/day of extended-release methylphenidate) or gradual withdrawal over 3 weeks, to 4 weeks of placebo. The primary outcome measure was the investigator-rated ADHD Rating Scale (ADHD-RS); secondary outcome measures were the investigator-rated Clinical Global Impressions improvement scale (CGI-I) and the Conners' Teacher Rating Scale-Revised: Short Form (CTRS-R:S). Continuous ratings were analyzed with mixed model for repeated measures analyses, and the CGI-I with a chi-square test.

RESULTS

The mean ADHD-RS scores at baseline for the continuation and discontinuation groups, respectively, were 21.4 (SD=9.7) and 19.6 (SD=8.9); after 7 weeks, the mean scores were 21.9 (SD=10.8) and 24.7 (SD=11.4), with a significant between-group difference in change over time of -4.6 (95% CI=-8.7, -0.56) in favor of the group that continued methylphenidate treatment. The ADHD-RS inattention subscale and the CTRS-R:S ADHD index and hyperactivity subscale also deteriorated significantly more in the discontinuation group. The CGI-I indicated worsening in 40.4% of the discontinuation group, compared with 15.9% of the continuation group.

CONCLUSIONS

Continued treatment with methylphenidate remains effective after long-term use. Some individual patients may, however, be withdrawn from methylphenidate without deterioration. This finding supports guideline recommendations that patients be assessed periodically to determine whether there is a continued need for methylphenidate treatment.

The effects of long-term medication on growth in children and adolescents with ADHD: an observational study of a large cohort of real-life patients

BACKGROUND

Children and adolescents with ADHD treated with central stimulants (CS) often have growth deficits, but the implications of such treatment for final height and stature remain unclear.

METHODS

Weight and height were assessed multiple times in 410 children and adolescents during long-term treatment with CS, which lasted between 0.9 and 16.1 years. Weight and height measures were converted to z-scores based on age- and sex-adjusted population tables.

RESULTS

CS treatment was associated with (1) a relative reduction in body weight and a temporary halt in growth, (2) a weight and height lag after 72 months compared with relative baseline values. No relation to early start of medication (<6 years), gender, comorbid ODD/CD or emotional disorders was observed.

CONCLUSIONS

Treatment with central stimulants for ADHD impacts growth in children and adolescents, and growth should be continuously monitored in patients on chronic treatment with these medications.

Baduk (the Game of Go) Improved Cognitive Function and Brain Activity in Children with Attention Deficit Hyperactivity Disorder

OBJECTIVE

Attention deficit hyperactivity disorder (ADHD) symptoms are associated with the deficit in executive functions. Playing Go involves many aspect of cognitive function and we hypothesized that it would be effective for children with ADHD.

METHODS

Seventeen drug naïve children with ADHD and seventeen age and sex matched comparison subjects were participated. Participants played Go under the instructor's education for 2 hours/day, 5 days/week. Before and at the end of Go period, clinical symptoms, cognitive functions, and brain EEG were assessed with Dupaul's ADHD scale (ARS), Child depression inventory (CDI), digit span, the Children's Color Trails Test (CCTT), and 8-channel QEEG system (LXE3208, Laxtha Inc., Daejeon, Korea).

RESULTS

There were significant improvements of ARS total score (z=2.93, p<0.01) and inattentive score (z=2.94, p<0.01) in children with ADHD. However, there was no significant change in hyperactivity score (z=1.33, p=0.18). There were improvement of digit total score (z=2.60, p<0.01; z=2.06, p=0.03), digit forward score (z=2.21, p=0.02; z=2.02, p=0.04) in both ADHD and healthy comparisons. In addition, ADHD children showed decreased time of CCTT-2 (z=2.21, p=0.03). The change of theta/beta right of prefrontal cortex during 16 weeks was greater in children with ADHD than in healthy comparisons (F=4.45, p=0.04). The change of right theta/beta in prefrontal cortex has a positive correlation with ARS-inattention score in children with ADHD (r=0.44, p=0.03).

CONCLUSION

We suggest that playing Go would be effective for children with ADHD by activating hypoarousal prefrontal function and enhancing executive function.

Abuse and dependence liability analysis of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder (ADHD): what have we learned?

Methylphenidate is the most prescribed stimulant medication for attention-deficit/hyperactivity disorder (ADHD). Despite the well documented clinical benefits of the drug, several questions remain unanswered concerning the effects of extended methylphenidate use (e.g. can methylphenidate be abused by ADHD patients? does repeated methylphenidate treatment produce addiction?). Preclinical studies can help address the long-term safety of clinical treatments, moreover animal studies provide valuable information on the details of drug actions. The spontaneously hypertensive rat (SHR), bred from normotensive Wistar Kyoto rat strain, is considered as the best validated and the most widely used animal model of ADHD. We reviewed the findings of research reports that investigated the abuse and dependence liability of methylphenidate in SHR. In particular, we surveyed the studies which investigated the effects of methylphenidate pretreatment on subsequent methylphenidate-induced conditioned place preference or self-administration for they may give insights into the abuse or dependence liability of long-term methylphenidate treatment in ADHD.

Cardiovascular considerations of attention deficit hyperactivity disorder medications: a report of the European Network on Hyperactivity Disorders work group, European Attention Deficit Hyperactivity Disorder Guidelines Group on attention deficit hyperactivity disorder drug safety meeting

Regulatory decisions regarding attention deficit hyperactivity disorder drug licensing and labelling, along with recent statements from professional associations, raise questions of practice regarding the evaluation and treatment of patients with attention deficit hyperactivity disorder. To address these issues for the European community, the European Network for Hyperkinetic Disorders, through its European Attention Deficit Hyperactivity Disorder Guidelines Group, organised a meeting between attention deficit hyperactivity disorder specialists, paediatric cardiovascular specialists, and representatives of the major market authorisation holders for attention deficit hyperactivity disorder medications. This manuscript represents their consensus on cardiovascular aspects of attention deficit hyperactivity disorder medications. Although sudden death has been identified in multiple young individuals on attention deficit hyperactivity disorder medication causing regulatory concern, when analysed for exposure using currently available data, sudden death does not appear to exceed that of the general population. There is no current evidence to suggest an incremental benefit to electrocardiography assessment of the general attention deficit hyperactivity disorder patient. Congenital heart disease patients have an increased prevalence of attention deficit hyperactivity disorder, and can benefit from attention deficit hyperactivity disorder therapies, including medication. The attention deficit hyperactivity disorder specialist is the appropriate individual to evaluate benefit and risk and recommend therapy in all patients, although discussion with a heart specialist is reasonable for congenital heart disease patients. For attention deficit hyperactivity disorder patients with suspected heart disease or risk factor/s for sudden death, assessment by a heart specialist is recommended, as would also be the case for a non-attention deficit hyperactivity disorder patient. The identification of risk factors for sudden death should not automatically exclude the use of attention deficit hyperactivity disorder medication.

Brain processes in discounting: consequences of adolescent methylphenidate exposure

Traits of inattention, impulsivity, and motor hyperactivity characterize children diagnosed with attention-deficit/hyperactivity disorder (ADHD), whose inhibitory control is reduced. In animal models, crucial developmental phases or experimental transgenic conditions account for peculiarities, such as sensation-seeking and risk-taking behaviors, and reproduce the beneficial effects of psychostimulants. An "impulsive" behavioral profile appears to emerge more extremely in rats when forebrain dopamine (DA) systems undergo remodeling, as in adolescence, or with experimental manipulation tapping onto the dopamine transporter (DAT). Ritalin(®) (methylphenidate, MPH), a DAT-blocking drug, is prescribed for ADHD therapy but is also widely abused by human adolescents. Administration of MPH during rats' adolescence causes a long-term modulation of their self-control, in terms of reduced intolerance to delay and diminished proneness for risk when reward is uncertain. Exactly the opposite profile emerges when exogenous alteration of DAT levels is achieved via lentiviral transfection. Both adolescent MPH exposure and DAT-targeting transfection lead to enduring hyperfunction of dorsal striatum and hypofunction of ventral striatum. Together with upregulation of prefronto-cortical phospho-creatine, striatal upregulation of selected genes (like serotonin 7 receptor gene) suggests that enhanced inhibitory control is generated by adolescent MPH exposure. Operant tasks, which assess the balance between motivational drives and inhibitory self-control, are thus useful for investigating reward-discounting processes and their modulation by DAT-targeting tools. In summary, due to the complexity of human studies, preclinical investigations of rodent models are necessary to understand better both the neurobiology of ADHD-like symptoms' etiology and the long-term therapeutic safety of adolescent MPH exposure.

Update on attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is now the most frequent diagnosis in children seen by Australian general paediatricians. It is a heterogeneous neurodevelopmental disorder and is usually accompanied by one or more co-morbid developmental and/or mental health conditions. In addition to daily symptoms, which often impair quality of life, ADHD can compromise educational and social development for the individual, and impact on families, schools and the broader community. Draft revised National Health and Medical Research Council Guidelines on ADHD were published in November 2009. This comprehensive document discusses the evidence in relation to many aspects of ADHD, which inform the large number of practice recommendations. Although there is an enormous literature on the causes, neurobiology and management of ADHD, there is still much to be learned particularly in relation to early intervention, behavioural therapies and factors influencing long-term outcomes.

Long-term treatment of ADHD with stimulants: a large observational study of real-life patients

OBJECTIVE

To evaluate 410 real-life patients treated with stimulants and assessed systematically over several years.

METHOD

Naturalistic observational study. A database was compiled on the basis of a review of the medical charts of patients attending a specialized ADHD clinic.

RESULTS

The diversity of ADHD patients was evident from the comorbidity, age at start, comedication, and treatment needs over time. Dosages corresponded to guidelines in most patients, but some needed higher dosages or got along on lower dosages for long periods. Age at start and comorbidity influenced dosage, and dosage was associated to differential outcome groups.

CONCLUSION

The study findings underscored the diversity of ADHD patients and that individual factors should be taken into account when tailoring individual treatment schedules. Findings further showed that stimulant dosages are dynamic over time and depend on individual factors, that individual factors influence outcome, and that patients with ADHD should be individually monitored and stimulant dosages adjusted continuously.

Use of ADHD drugs in the Nordic countries: a population-based comparison study

OBJECTIVE

To compare national use of attention-deficit/hyperactivity disorder (ADHD) drugs between five Nordic countries.

METHOD

A population-based drug utilisation study based on nationwide prescription databases, covering in total 24 919 145 individuals in 2007. ADHD drugs defined according to the World Health Organization Anatomic Therapeutic Chemical classification system as centrally acting sympathomimetics (N06BA).

RESULTS

The 2007 prevalence of ADHD drug use among the total Nordic population was 2.76 per 1000 inhabitants, varying from 1.23 per 1000 in Finland to 12.46 per 1000 in Iceland. Adjusting for age, Icelanders were nearly five times more likely than Swedes to have used ADHD drugs (Prev.Ratio = 4.53, 95% CI: 4.38-4.69). Prevalence among boys (age 7-15) was fourfold the prevalence among girls (Prev.Ratio = 4.28, 95% CI: 3.70-4.96). The gender ratio was diminished among adults (age 21 +) (Prev.Ratio = 1.24, CI: 1.21-1.27).

CONCLUSION

A considerable national variation in use of ADHD drugs exists between the Nordic countries.

A one year trial of methylphenidate in the treatment of ADHD

OBJECTIVE

To determine the effects of long-term methylphenidate treatment on symptom severity and social adjustment in adult ADHD.

METHOD

Adults (n = 116) meeting operational diagnostic criteria for ADHD (the "Utah Criteria") entered a randomized double-blind crossover trial of methylphenidate and placebo. Participants who improved on immediate-release methylphenidate entered a 12-month, open-label trial. Outcomes were assessed using the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS), Clinical Global Impression-Improvement (CGI-I), global assessment of functioning (GAF), and the Weissman Social Adjustment Scale (WSAS).

RESULTS

In the double-blind trial more patients improved (50% reduction of symptoms) receiving methylphenidate (74%) than placebo (21%, p = .001). During the open-label trial, symptom severity decreased 80% from baseline, and the WSAS decreased >50% in all subscales. The average GAF improved significantly (p < .0001).

CONCLUSION

ADHD adults, who responded to methylphenidate in a short-tem, placebo-controlled trial, responded to long-term treatment with marked improvements in ADHD symptoms and psychosocial functioning.

Long-term efficacy of methylphenidate in enhancing attention regulation, social skills, and academic abilities of childhood cancer survivors

PURPOSE

Methylphenidate (MPH) ameliorates attention problems experienced by some cancer survivors in the short term, but its long-term efficacy is unproven.

PATIENTS AND METHODS

This study investigates the long-term effectiveness of maintenance doses of MPH in survivors of childhood brain tumors (n = 35) and acute lymphoblastic leukemia (n = 33) participating in a 12-month MPH trial. Measures of attention (Conners' Continuous Performance Test [CPT], Conners' Rating Scales [CRS]), academic abilities (Wechsler Individual Achievement Test [WIAT]), social skills (Social Skills Rating System [SSRS]), and behavioral problems (Child Behavior Checklist [CBCL]) were administered at premedication baseline and at the end of the MPH trial while on medication. A cancer control group composed of patients who were not administered MPH (brain tumor = 31 and acute lymphoblastic leukemia = 23) was assessed on the same measures 12 [corrected] months apart.

RESULTS

For the MPH group, repeated measures analysis of variance revealed significant improvement in performance on a measure of sustained attention (CPT indices, P < .05); parent, teacher, and self-report ratings of attention (CRS indices, P < .05), and parent ratings of social skills or behavioral problems (SSRS and CBCL indices; P < .05). In contrast, the cancer control group only showed improvement on parent ratings of attention (Conners' Parent Rating Scale indices; P < .05) and social skills (SSRS and CBCL indices; P < .05). There was no significant improvement on the academic measure (WIAT) in either group.

CONCLUSION

Attention and behavioral benefits of MPH for childhood cancer survivors are maintained across settings over the course of a year. Although academic gains were not identified, MPH may offer benefits in academic areas not assessed.

Effects of acute and chronic administration of atomoxetine and methylphenidate on extracellular levels of noradrenaline, dopamine and serotonin in the prefrontal cortex and striatum of mice

Acute administration of atomoxetine and methylphenidate, attention-deficit/hyperactivity disorder (ADHD) drugs, activates catecholaminergic systems in rat brain, but the effects of their chronic administration are not known. This study examined the effects of acute and chronic administration of ADHD drugs on the extracellular levels of noradrenaline (NA), dopamine (DA) and serotonin (5-HT), and the expression of the neuronal activity marker c-Fos in the prefrontal cortex and striatum of mice. Acute ADHD drugs increased NA and DA, but not 5-HT, levels in the prefrontal cortex of mice. Maximal effects of atomoxetine and methylphenidate were observed at 1 mg/kg and 3 mg/kg, respectively. At these doses, both drugs did not affect the spontaneous locomotor activity of mice. Chronic administration of atomoxetine 1 mg/kg and methylphenidate 3 mg/kg for 21 days also increased NA and DA, but not 5-HT, levels in the prefrontal cortex. The increases in NA levels induced by atomoxetine, but not methylphenidate, were reduced by chronic treatment. In contrast, acute and chronic administration of atomoxetine 1 mg/kg and methylphenidate 3 mg/kg did not affect the monoamine levels in the striatum. Acute and chronic atomoxetine 1 mg/kg and methylphenidate 3 mg/kg increased the expression of c-Fos in the prefrontal cortex, but not in the striatum, to a similar extent. These results suggest that acute and chronic administration of the ADHD drugs selectively activate the prefrontal catecholamine systems in mice.

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.'

Central stimulants in the treatment of attention-deficit hyperactivity disorder (ADHD) in children and adolescents. A naturalistic study of the prescription in Sweden, 1977-2007

BACKGROUND

An increased prescription of central stimulants (CS) for treatment of attention-deficit hyperactivity disorder (ADHD) in children and adolescents has been reported in Sweden.

AIMS

To follow-up the treatment with CS as concerns total as well as regional differences in prescription rate. Efficacy and side-effects reported and gender differences in prescription over time also have been summarized.

METHODS

Data from the Swedish Medical Products Agency (MPA) of individual licences, annual reports about patients on individual or clinic licences from the MPA and sales statistics from the National Pharmacy (Apoteket AB) have been used.

RESULTS

The number of new licences and prescriptions increased dramatically from 1992 to 2007 and a change of preparations was seen. Great differences (fivefold) between the 21 counties of Sweden were noticed. In the follow-up reports to the MPA, a good/moderate treatment effect was reported in 92% and adverse effects were reported in 4% leading to discontinuation of medication in 46% of them. Abuse/misuse of the preparation was suspected in 0.2% of the reports. A tendency of a reduction of the proportion of boys to girls treated through individual licences has been seen.

CONCLUSIONS

The study, although observational, supports good efficacy, limited adverse effects and a low degree of misuse in clinical use of CS for children and adolescents with ADHD.

Self-esteem in adolescent patients with attention-deficit/hyperactivity disorder during open-label atomoxetine treatment: psychometric evaluation of the Rosenberg Self-Esteem Scale and clinical findings

To report on (1) psychometric properties of the Rosenberg Self-Esteem Scale (SES) studied in adolescents with ADHD, (2) correlations of SES with ADHD scale scores, and (3) change in patient-reported self-esteem with atomoxetine treatment. ADHD patients (12–17 years), treated in an open-label study for 24 weeks. Secondary analyses on ADHD symptoms (assessed with ADHD-RS, CGI, GIPD scales) and self-esteem (SES) were performed. One hundred and fifty-nine patients were treated. A dichotomous structure of the SES could be confirmed. Reliability and internal consistency were moderate to excellent. Highest coefficients were found for the correlation between SES and GIPD scores. Self-esteem significantly increased over time, accompanied by an improvement of ADHD symptoms and related perceived difficulties. The Rosenberg SES was shown to be internally consistent, reliable, and sensitive to treatment-related changes of self-esteem. According to these findings, self-esteem may be an important individual patient outcome beyond the core symptoms of ADHD.

Occupational outcome in adult ADHD: impact of symptom profile, comorbid psychiatric problems, and treatment: a cross-sectional study of 414 clinically diagnosed adult ADHD patients

OBJECTIVE

To determine the effects of symptom profile, comorbid psychiatric problems, and treatment on occupational outcome in adult ADHD patients.

METHOD

Adult ADHD patients (N = 414) responded to questionnaires rating past and present symptoms of ADHD, comorbid conditions, treatment history, and work status.

RESULTS

Of the patients, 24% reported being in work, compared to 79% in a population-based control group (N = 359). Combined subtype of ADHD, substance abuse, and a reported history of depression or anxiety were correlated with being out of work. Current and past medical treatment of ADHD was correlated with being in work. Logistic regression analyses showed that stimulant therapy during childhood was the strongest predictor for being in work as adults (odds ratio = 3.2, p = .014).

CONCLUSION

Early recognition and treatment of ADHD is a strong predictor of being in work as an adult, independently of comorbidity, substance abuse, and current treatment.

Psychopharmacology of ADHD in pediatrics: current advances and issues

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral developmental disorder found in 3% to 8% of children and adolescents. An important part of ADHD management is psychopharmacology, which includes stimulants, norepinephrine reuptake inhibitors, alpha-2 agonists, and antidepressants. Medications with the best evidence-based support for ADHD management are the stimulants methylphenidate and amphetamine. A number of newer, long-acting stimulants are now available and a number of new medications are considered that are under current research.

Methylphenidate potentiates morphine-induced antinociception, hyperthermia, and locomotor activity in young adult rats

The goal of this study was to determine if the exaggerated morphine-induced conditioned place preference (CPP) response seen in adult rats after preweanling methylphenidate exposure is unique to reward-mediated behaviors or is indicative of generalized changes in opioid-mediated behaviors. Rats were exposed to saline or methylphenidate (2.0 or 5.0 mg/kg) for 10 consecutive days starting on postnatal (PD) 11 with testing beginning on PD 60. In Experiment 1, morphine-induced (0, 2.5, 5.0 or 10.0 mg/kg) antinociception was assessed using the tail immersion and hot plate tasks. In Experiment 2, morphine-induced (0, 2.5, 5.0, or 10.0 mg/kg) hyperthermia and locomotor activity were measured. Morphine caused an increase in antinociception, with early methylphenidate (5.0 mg/kg) exposure potentiating the effects of 5.0 mg/kg morphine. Rectal temperatures were elevated after morphine, with the greatest increase occurring in male rats. Methylphenidate potentiated the hyperthermic effects of morphine (10.0 mg/kg) but only in males. Moderate doses (2.5 and 5.0 mg/kg) of morphine increased the locomotor activity of adult rats, while a higher dose (10.0 mg/kg) decreased locomotion. Interestingly, methylphenidate-pretreated females showed increased locomotor activity relative to controls. These results suggest that early methylphenidate exposure induces general changes in opioid system functioning that are not specific to reward-mediated behaviors.

Global issues related to the impact of untreated attention-deficit/hyperactivity disorder from childhood to young adulthood

Attention-deficit/hyperactivity disorder (ADHD) is a common, chronic, and costly disorder, with an impact that can span from preschool into adulthood. There are safe and effective therapies that can manage and help prevent many of the associated negative outcomes of ADHD, but treatment rates are far from optimal and considerable obstacles exist in achieving satisfactory treatment adherence. Individuals with untreated ADHD, their families, and other caregivers must be made aware of the impact that this disorder may have on them at every stage of life and, correspondingly, the improved outcomes that can be achieved with the successful management of ADHD.

Academic and educational outcomes of children with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is associated with poor grades, poor reading and math standardized test scores, and increased grade retention. ADHD is also associated with increased use of school-based services, increased rates of detention and expulsion, and ultimately with relatively low rates of high school graduation and postsecondary education. Children in community samples who show symptoms of inattention, hyperactivity, and impulsivity with or without formal diagnoses of ADHD also show poor academic and educational outcomes. Pharmacologic treatment and behavior management are associated with reduction of the core symptoms of ADHD and increased academic productivity, but not with improved standardized test scores or ultimate educational attainment. Future research must use conceptually based outcome measures in prospective, longitudinal, and community-based studies to determine which pharmacologic, behavioral, and educational interventions can improve academic and educational outcomes of children with ADHD.

Long-acting methylphenidate has an effect on aggressive behavior in children with attention-deficit/hyperactivity disorder

INTRODUCTION

Aggression is frequently observed in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to assess the efficacy with regard to oppositional and aggressive behavior of a new long-acting methylphenidate preparation (Medikinet retard, MPH-MR), with equal portions of the immediate-release and the sustained-release active substance, and especially to look at correlations between either teacher or parent assessment of aggression and ADHD sub-symptomatology.

METHODS

Eighty five children and adolescents (6-16 years) were investigated in a double-blind, randomized, clinical trial over 5 weeks under a treatment with MPH-MR using symptom checklists for ADHD, oppositional-defiant and conduct disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV).

RESULTS

A total of 64.9% of the children showed oppositional defiant disorder/conduct disorder (ODD/CD) symptoms. A statistically significant effect was found in the group treated with MPH (verum-group). On the basis of Cohen's criteria, high effects were found for aggressive symptoms in school (d = 1.0), but not in the afternoon (d = 0.4). There were also lower effect sizes for more severe aggressive symptoms. We found characteristic correlations between ODD/CD symptoms and the ADHD subscale hyperactivity/impulsivity compared to the subscale inattention.

CONCLUSIONS

Long-acting MPH is effective in the treatment of oppositional-defiant and aggressive behavior, especially concerning milder symptoms. The expected correlation between impulsivity and aggressiveness could be confirmed.

Methylphenidate reduces impulsive behaviour in juvenile Wistar rats, but not in adult Wistar, SHR and WKY rats

RATIONALE

Impulsivity is a core symptom of attention deficit/hyperactivity disorder (ADHD). The spontaneously hypertensive rats (SHR) is a strain commonly used as an animal model of ADHD. However, there is no clear evidence that psychostimulants, which are used for treatment of ADHD, reduce impulsivity in SHR. Because ADHD mainly affects children, it may be relevant to study psychostimulants on juvenile animals.

OBJECTIVES

Using tolerance to delay of reward as index of impulsivity, the effects of methylphenidate were assessed in adult SHR, Wistar Kyoto (WKY) and Wistar rats and in juvenile Wistar rats.

MATERIALS AND METHODS

Animals were trained in a T-maze to choose between a small-but-immediate and a large-but-delayed reward. Adult SHR, WKY and Wistar rats were compared for their ability to tolerate a 15-s delay. The effect of methylphenidate on the tolerance to a 30-s delay was studied in adult rats of the three strains and in juvenile (4.5 to 6.5-week-old) Wistar rats.

RESULTS

In adult rats, the waiting ability was lower in SHR than in control strains. Waiting ability was improved by methylphenidate (3 and 5 mg/kg) in juveniles, but not by methylphenidate (3 mg/kg) in adults.

CONCLUSIONS

These data support the idea that SHR are more impulsive than control strains. However, at the dose studied, methylphenidate fails to improve tolerance to delay in adult rats whatever the strain used. The reduction of impulsivity induced by methylphenidate in juvenile Wistar rats indicates that juvenile animals may be suitable for testing the therapeutic potential of drugs intended to the treatment of ADHD in children.

A randomized, double-blind, placebo-controlled clinical trial on once-daily atomoxetine in Taiwanese children and adolescents with attention-deficit/hyperactivity disorder

OBJECTIVE

The aim of this study was to assess the efficacy and safety of the once-daily atomoxetine compared with placebo in pediatric patients with attention-deficit/hyperactivity disorder (ADHD) in Taiwan.

METHOD

The study sample included 106 patients aged 6-16 years who met the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria of ADHD randomly assigned to atomoxetine once daily (n = 72) and placebo once daily (n = 34) in a double-blind, 6-week treatment study. The primary efficacy measure was the total score of the ADHD Rating Scale-IV Parents Version: Investigator Administered and Scored. The secondary efficacy measures included the Clinical Global Impressions--ADHD--Severity and Chinese Conner's Parent and Teacher Rating Scale--Revised: Short Form. Data were analyzed on an intent-to-treat basis and a last-observation-carried-forward approach.

RESULTS

The two treatment groups did not differ in demographics and baseline measures. Compared to the placebo group, the atomoxetine group showed significantly greater reductions in ADHD-related symptoms according to the ratings of investigators, parents, and teachers. The treatment effect size of the primary efficacy measure was 0.70 at the end of study. Adverse events reported significantly more frequently with atomoxetine were decreased appetite (36.1%) and nausea (16.6%). No drug-related serious adverse event was observed.

CONCLUSIONS

Once-daily atomoxetine is an effective, well-tolerable, and safe treatment for children and adolescents with ADHD in Taiwan.

Evidence-based guidelines for management of attention-deficit/hyperactivity disorder in adolescents in transition to adult services and in adults: recommendations from the British Association for Psychopharmacology

Attention-deficit/hyperactivity disorder (ADHD) is an established diagnosis in children, associated with a large body of evidence on the benefits of treatment. Adolescents with ADHD are now leaving children's services often with no readily identifiable adult service to support them, which presents problems as local pharmacy regulations often preclude the prescription of stimulant drugs by general practitioners (GPs). In addition, adults with ADHD symptoms are now starting to present to primary care and psychiatry services requesting assessment and treatment. For these reasons, the British Association for Psychopharmacology (BAP) thought it timely to hold a consensus conference to review the body of evidence on childhood ADHD and the growing literature on ADHD in older age groups. Much of this initial guidance on managing ADHD in adolescents in transition and in adults is based on expert opinion derived from childhood evidence. We hope that, by the time these guidelines are updated, much evidence will be available to address the many directions for future research that are detailed here.

Attention-deficit/hyperactivity disorder with obstructive sleep apnea: a treatment outcome study

BACKGROUND

Children diagnosed with attention-deficit/hyperactivity disorder (ADHD), based on Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM-IV) criteria, may also have obstructive sleep apnea (OSA), but it is unclear whether treating OSA has similar results as methylphenidate (MPH), a commonly used treatment for ADHD.

METHODS

This study enrolled 66 school-age children, referred for and diagnosed with ADHD, and 20 healthy controls. Polysomnography (PSG) performed after ADHD diagnosis showed the presence of mild OSA. After otolaryngological evaluation, parents and referring physicians of the children could select treatment of ADHD with MPH, treatment of OSA with adenotonsillectomy or no treatment. Systematic follow-up was performed six months after initiation of treatment, or diagnosis if no treatment. All children had pre- and post-clinical interviews; pediatric, neurologic, psychiatric and neurocognitive evaluation; PSG; ADHD rating scale, child behavior checklist (CBCL) filled out by parents and teacher; test of variables of attention (TOVA); and the quality of life in children with obstructive sleep disorder questionnaire (OSA-18).

RESULTS

ADHD children had an apnea-hypopnea index (AHI)>1<5 event/hour; 27 were treated with MPH, 25 had adenotonsillectomy, and 14 had no treatment. The surgical and MPH groups improved more than the non-treatment group. When comparing MPH to post-surgery, the PSG and questionnaire sleep variables, some daytime symptoms (including attention span) and TOVA subscales (impulse control, response time and total ADHD score) improved more in the surgical group than the MPH group. The surgical group had an ADHD total score of 21.16+/-7.13 on the ADHD rating scale (ADHD-RS) post-surgery compared to 31.52+/-7.01 pre-surgery (p=0.0001), and the inattention and hyperactivity subscales were also significantly lower (p=0.0001). Finally, the results were significantly different between surgically and MPH-treated groups (ADHD-RS p=0.007). The surgical group also had a TOVA ADHD score lower than -1.8 and close to those obtained in normal controls.

CONCLUSION

A low AHI score of >1 considered abnormal is detrimental to children with ADHD. Recognition and surgical treatment of underlying mild sleep-disordered breathing (SDB) in children with ADHD may prevent unnecessary long-term MPH usage and the potential side effects associated with drug intake.

Use of double-blind placebo-controlled N-of-1 trials among stimulant-treated youths in The Netherlands: a descriptive study

OBJECTIVES

An N-of-1 trial is a double-blind placebo-controlled randomized trial to objectively and systematically evaluate the individual's response. This approach seems extraordinarily suitable for assessing the efficacy of stimulants in the treatment of attention deficit hyperactivity disorder (ADHD). The aim is to examine the use of N-of-1 trials among youths in the Netherlands, the protocols used, and the continuation of stimulant treatment thereafter.

METHODS

Physicians requesting N-of-1 trials with stimulants were interviewed about their rationale and protocol. Prevalence and continuation were investigated by extracting N-of-1 trials among youths <20 years of age from a large pharmacy dispensing database for 2000-2004.

RESULTS

The main purpose of N-of-1 trials mentioned by physicians was the assessing of individuals' response and dose-finding. Trial length, dosing schedule and efficacy assessment differed per physician. Trials consisted of a maximum of two treatment periods per dose. The annual percentage of youths starting stimulant treatment with an N-of-1 trial fluctuated between 0.6% (3/462) and 3.3% (10/301). No statistical significant difference could be detected between the continuation of stimulant treatment with or without an N-of-1 trial (p = 0.71).

CONCLUSIONS

N-of-1 trials with stimulants are infrequently and not optimally used in the Netherlands. The results of N-of-1 protocols described by physicians are of questionable value, due to the small number of treatment periods per dose. More uniformity in the protocols would make it easier to encompass the N-of-1 methodology in physicians' daily practice.

Remission versus response as the goal of therapy in ADHD: A new standard for the field?

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) has a substantial negative impact; however, within long-term follow-up studies, a proportion of patients do very well, both symptomatically and functionally, suggesting that the lower the symptom burden, the greater the functional improvements. Studies in major depressive disorder have identified a relationship between symptomatic remission and restoration of normal functioning.

OBJECTIVE

The purpose of this article was to propose a definition of remission in ADHD, review remission rates in clinical trials for commonly used medications, and explore the relationship between symptomatic remission and optimal functioning.

METHODS

Remission and response rates for medications were obtained through MEDLINE searches of English-language citations (1999-2005) and meeting abstracts (2003-2005) using the terms amphetamine, atomoxetine, methylphenidate, ADHD, efficacy, effectiveness, and controlled trial, as well as hand searches of efficacy studies. Evidence from randomized controlled trials, as well as effectiveness studies, where the proportions of patients achieving predefined cutoff points for remission or response are reported, was reviewed. Because higher remission rates were identified with the oral, osmotic, controlled-release system (OROS) of methylphenidate, a relationship between symptomatic response/remission and optimal functioning was explored further.

RESULTS

Remission in ADHD should be defined as a loss of diagnostic status, minimal or no symptoms, and optimal functioning when individuals are being treated with or without medication. Symptomatic remission can be operationalized as a mean total score of S1 on most standardized questionnaires. For the medications examined (OROS methylphenidate, immediate-release methylphenidate, atomoxetine, and mixed amphetamine salts), response rates were comparable at approximately 70% to 75%; however, remission rates were higher with OROS methylphenidate compared with either immediate-release methylphenidate or atomoxetine (remission rates with amphetamines were not found). Benefits, including decreased illness burden as well as improved psychosocial and academic functioning, were associated with treatment versus no treatment and were greater with medication that offered higher remission rates.

CONCLUSIONS

The literature provided evidence that greater symptom improvements are associated with greater functional improvements, emphasizing that remission of ADHD as defined should be the goal of therapy. Treatment ought to include the early use of strategies with the greatest chance of achieving remission. Future clinical research should use remission as the primary outcome.

Stimulants: Therapeutic actions in ADHD

Stimulants such as methylphenidate and amphetamine are currently the most common treatment for attention deficit hyperactivity disorder (ADHD). For years, it was assumed that stimulants had paradoxical calming effects in ADHD patients, whereas stimulating 'normal' individuals and producing locomotor activation in rats. It is now known that low doses of stimulants focus attention and improve executive function in both normal and ADHD subjects. Furthermore, the seminal work of Kuczenski and Segal showed that low, oral doses of methylphenidate reduce locomotor activity in rats as well. Berridge et al have now shown that these low doses produce marked increases in norepinephrine and dopamine release in the prefrontal cortex, whereas having only subtle effects on subcortical catecholamine release. ihe prefrontal cortex regulates behavior and attention using representational knowledge, and imaging and neuropsychological studies have shown that the prefrontal cortex is weaker in subjects with ADHD. This cortical area is very sensitive to levels of catecholamines: moderate levels engage postsynaptic alpha2A-adrenoceptors and D1 receptors and improve prefrontal regulation of behavior and attention, while high levels impair prefrontal function via alpha1-adrenoceptors and excessive D1 receptor stimulation. Administering low doses of methylphenidate to rats improves the working memory and attentional functions of the prefrontal cortex, while high doses impair working memory and produce a perseverative pattern of errors similar to that seen in patients. The low dose improvement is hiocked by either an alpha2-adrenoceptor or Dl receptor antagonist, suggesting that both norepinephrine and dopamine contribute to the beneficial actions of stimulant medications.

Nonmedical use of prescription stimulants in the United States

OBJECTIVE

This study estimated prevalences and correlates of stimulant diversion in the United States and examined relationships between diversion and measures of abuse or dependence.

METHODS

We conducted descriptive and multivariate analysis of data from the National Survey on Drug Use and Health. Key measures were nonmedical use (misuse) of any prescription stimulant, any stimulant other than methamphetamine, and stimulants indicated for attention-deficit/hyperactivity disorder (ADHD).

RESULTS

Lifetime stimulant misuse included some misuse of longer-acting ADHD drugs. The majority of past-year misuse involved drugs other than methamphetamine, particularly for youth aged 12-17. Past year misuse was more prevalent among persons aged 12-25, compared with older adults, and among Whites, compared with other groups. Prevalences in large metropolitan areas were lower than or similar to those in less populated areas. About 13% of past-year stimulant misusers met the survey criteria for dependence or abuse, as did about 10% of persons aged 12-25 who misused only nonmethamphetamine stimulants.

CONCLUSIONS

Most stimulant misuse in the United States (particularly among youth) involved prescription drugs other than methamphetamine. The problem is not limited to metropolitan areas.

Parents report on stimulant-treated children in the Netherlands: initiation of treatment and follow-up care

OBJECTIVES

The aim of this study was to describe current practices around initiation and follow-up care of stimulant treatment among stimulant-treated children in a nationwide survey among parents.

METHODS

A total of 115 pharmacies detected current stimulant users <16 years old in their pharmacy information system and sent parents a questionnaire regarding their child's stimulant treatment.

RESULTS

Parents returned 924 of 1,307 questionnaires (71%). The median age of the stimulant users was 10 years and 85% were boys. In all, 91% were diagnosed with attention-deficit/hyperactivity disorder (ADHD). In 77% of the cases, the child or parents received other therapies besides stimulants-21% received psychotropic co-medication, with melatonin (11%) and antipsychotics (7%) being mentioned most frequently. Stimulant use was primarily initiated by child psychiatrists (51%) and pediatricians (32%), but most children received repeat prescriptions from general practitioners (61%). Of these 924 children, 19% did not receive any follow-up care, and transfer of prescribing responsibility increased the risk of not receiving follow-up care. The 732 children (79%) who were monitored visited a physician approximately twice a year. During follow-up visits, pediatricians performed physical check ups significantly more often.

CONCLUSION

Stimulant treatment in The Netherlands is initiated mainly by specialists such as child psychiatrists and pediatricians. In the current study, follow-up care for stimulant-treated children in The Netherlands appeared to be poor, suggesting an urgent need for improvement.

Attention-deficit hyperactivity disorder in girls: epidemiology and management

Attention-deficit hyperactivity disorder (ADHD) in girls is a topic of growing research and clinical interest. For many years, girls with ADHD have been ignored and overshadowed by hyperkinetic and impulsive boys, but they are now attracting interest in an effort to understand the similarities and differences in the prevalence, symptoms, familial risk, comorbidities and treatment of ADHD in the two sexes. A review of past and current literature finds that the symptoms of ADHD are not sex specific, but that identification of girls with ADHD is hampered by parental and teacher bias, and confusion. Girls are more likely to be inattentive without being hyperactive or impulsive, compared with boys. Girls and boys share the same familial risk patterns, as well as similar, although not identical, comorbidity or impairment patterns. The risk of non-treatment is as great in girls as it is in boys; up to 70-80% of identified children will have persistent symptoms and impairment that extends into adolescence and adulthood. Treatment modalities are equally effective in girls and boys. Stimulants, non-stimulants and behavioural modalities are the mainstays of effective treatment.

ADHD in adults: a study of clinical characteristics, impairment and comorbidity

In this study, we explored the clinical characteristics, impairment and comorbidity in a sample of 45 adult patients with attention-deficit/hyperactivity disorder (ADHD). The collection of data is based on a naturalistic, retrospective approach using medical records documenting a comprehensive assessment of the patients. The sample was severely impaired in terms of academic achievement, employment and criminality, and had very high levels of comorbidity, especially alcohol and drug abuse, antisocial personality disorder and depression. Despite a high degree of contact with child psychiatric services in childhood, very few were diagnosed with ADHD, and many had a long period of psychiatric treatment as adults before the ADHD diagnosis was made. ADHD is in this sample of adults associated with severe impairment and comorbidity, and the connection between impairment and lack of proper diagnosis and treatment is discussed.

The epidemiology of psychotropic drug use in children and adolescents

Despite the scarcity of evidence on the safety and efficacy of psychotropic drugs in the paediatric population, especially in the long-term, several epidemiological studies have reported an increase in their prescription rates. This increase is especially evident for stimulants and selective serotonin reuptake inhibitors. An analysis of the epidemiological data suggests that the risk of inappropriate use or abuse of these drugs is high. In such a context, not only is additional, independent and transparent research necessary, but also children with mental disorders (and their parents) must be guaranteed appropriate care.