Serum and brain concentrations of methylphenidate: implications for use and abuse

When used to treat children with Attention Deficit Hyperactivity Disorder, methylphenidate (MPH) acts primarily by blocking the dopamine (DA) transporter (DAT) and increasing extracellular DA in the striatum. This is strikingly similar to the mechanism of action of cocaine, a primary stimulant drug of abuse. When administered intravenously, MPH like cocaine has reinforcing effects (euphoria) at doses that exceed a DAT blockade threshold of 60%. When administered orally at clinical doses, the pharmacological effects of MPH also exceed this threshold, but reinforcing effects rarely occur. Here we discuss the pharmacokinetic properties of MPH in serum (and in brain) that differ for oral and intravenous routes of administration and the importance of acute tolerance in determining pharmacodynamic effects in clinical use and illegal abuse. We suggest that intravenous administration of MPH mimics the rapid phasic cell firing of DA neurons, which may be a critical factor associated with reinforcing effects and abuse, while oral administration of MPH mimics the tonic DA cell firing, which may be a critical factor associated with clinical effects.

Guidelines and algorithms for the use of methylphenidate in children with Attention-Deficit/ Hyperactivity Disorder

OBJECTIVE

To review published algorithms for guiding the use of methylphenidate (MPH) in the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) in children and adolescents.

METHODS

A consensus roundtable of 12 experts was convened to review the evidence for the safety and efficacy of MPH in the treatment of ADHD, as well as the published algorithms and practice guidelines for using MPH. The experts reviewed the algorithms for practicality and acceptability by clinicians.

RESULTS

Algorithms that included MPH commonly selected it as the initial medication to be employed in the treatment of children with ADHD. Factors involved included its high efficacy, good safety record, and the ubiquitous nature of its appearance in the ADHD treatment literature.

CONCLUSIONS

MPH should be considered as the first medication to be used in a treatment algorithm for children and adolescents with ADHD.

The use of a laboratory school protocol to evaluate concepts about efficacy and side effects of new formulations of stimulant medications

Recently, new long-acting formulations of racemic methylphenidate (MPH: Ritalin LA, Metadate CD and Concerta) and amphetamine (AMP: Adderall XR) were developed and are now approved by the Food and Drug Administration (FDA). In addition, dexmethylphenidate (Focalin), the pharmacologically active d-threo enantiomer of MPH, also was approved by the FDA. In the initial phases of development, prototypes of these five new formulations were evaluated using the University of California, Irvine (UCI) Laboratory School Protocol (LSP), in which surrogate measures of efficacy are collected in highly controlled settings rather than clinical measures of effectiveness in the less-controlled, natural environments of home or school. The LSP studies were followed by large effectiveness and safety studies required for gaining FDA approval. These initial efficacy and side effect studies in the LSP provided missing information about the basic pharmacokinetic (PK) and pharmacodynamic (PD) properties of MPH and AMP and produced some new discoveries (i.e., acute tolerance) that were used to help design the final products. The final once-a-day formulations used different drug delivery systems to achieve long-acting efficacy (Ritalin LA, Metadate CD, Concerta, Adderall XR). All four drug delivery systems were based on two processes: first, a bolus delivery (BD) process to achieve rapid onset of efficacy (mg), and second, a controlled delivery (CD) process to achieve rates of delivery (mg/hr) or a delayed bolus (mg) to maintain efficacy. A theoretical approach was used to compare and contrast the new once-a day formulations of MPH by selecting total daily doses (mg/d) that would equate drug delivery by the first process (mg of the initial bolus) and the second process (mg/hr over specified time period). In addition to efficacy, applications of the LSP to measure common side effects related to eating and sleeping were described and discussed.

High prevalence of rare dopamine receptor D4 alleles in children diagnosed with attention-deficit hyperactivity disorder

Associations have been reported of the 7-repeat (7R) allele of the human dopamine receptor D4 (DRD4) gene with both the personality trait of novelty seeking and attention-deficit/hyperactivity disorder (ADHD). The increased prevalence of the 7R allele in ADHD probands is consistent with the common variant-common disorder hypothesis, which proposes that the high frequency of many complex genetic disorders is related to common DNA variants. Recently, based on the unusual DNA sequence organization and strong linkage disequilibrium surrounding the DRD4 7R allele, we proposed that this allele originated as a rare mutational event, which nevertheless increased to high prevalence in human populations by positive selection. We have now determined, by DNA resequencing of 250 DRD4 alleles obtained from 132 ADHD probands, that most ADHD 7R alleles are of the conserved haplotype found in our previous 600 allele worldwide DNA sample. Interestingly, however, half of the 24 haplotypes uncovered in ADHD probands were novel (not one of the 56 haplotypes found in our prior population studies). Over 10 percent of the ADHD probands had these novel haplotypes, most of which were 7R allele derived. The probability that this high incidence of novel alleles occurred by chance in our ADHD sample is much less than 0.0001. These results suggest that allelic heterogeneity at the DRD4 locus may also contribute to the observed association with ADHD.

Pharmacokinetic and pharmacodynamic properties of stimulants: implications for the design of new treatments for ADHD

In the USA, the stimulant drug methylphenidate (MPH) is used to treat a large number (2 million or more per year) of children with Attention Deficit Hyperactivity Disorder (ADHD). Although the US FDA approved MPH in the 1960s, the pharmacokinetic (PK) properties of serum concentrations of MPH in children with ADHD were not described until the 1980s, and then in only a few cases. Recently, information from drug development programs have increased our knowledge about the serum PK and some pharmacodynamic (PD) characteristics of MPH in ADHD children, and studies based on positron emission tomograpy (PET) in adult volunteers have provided new knowledge about the PK properties of MPH at the primary site of action in the brain. We will review these two topics and use this new information to evaluate the mechanisms of action of MPH.

Performance and error analysis of automated external defibrillator use in the out-of-hospital setting

STUDY OBJECTIVE

We determined whether automated external defibrillators (AEDs) can meet the American Heart Association performance criteria to detect and shock unstable cardiac rhythms (ventricular fibrillation [VF], ventricular tachycardia [VT]) in the setting of an out-of-hospital cardiac arrest.

METHODS

AED performance was reviewed for cardiac arrests occurring between January 1, 1995, and December 31, 1997. After every cardiac arrest, data regarding each rhythm analyzed and subsequent response (shock or no shock) were downloaded from the AED memory module. The study paramedic and study physician independently reviewed each case and interpreted cardiac rhythms from downloaded AED data. The emergency medical services medical director resolved all discrepancies in a blinded manner. All cases of out-of-hospital cardiac arrest in which an AED was turned on and a rhythm analyzed were included. The primary objective was the correct identification and defibrillation of VF or VT. Sensitivity, specificity, and predictive values with 95% confidence intervals (CIs) were calculated. Sources of error in AED rhythm management are also described.

RESULTS

A total of 3,448 AED rhythms were available for interpretation. Sensitivity and specificity for appropriate AED management of a shockable (VF or VT) rhythm were 81.0% (95% CI 77.9% to 83.8%) and 99.9% (95% CI 99.7% to 100%), respectively. Positive and negative predictive values were 99.6% (95% CI 98.7% to 99.9%) and 95.5% (95% CI 94.7% to 96.2%), respectively. There were 132 errors associated with AED management. Two errors resulted in delivery of an inappropriate shock. In the remaining 130 errors, a shockable rhythm was not shocked. Fifty-five (42.3%) errors were AED dependent, 70 (53.9%) were operator dependent, and 5 (3.9%) were unclassified.

CONCLUSION

The AED had high specificity and moderately high sensitivity in detecting and shocking unstable cardiac rhythms in the out-of-hospital setting. Few cardiac rhythms were mismanaged by the AED. Elimination of operator-dependent errors could increase AED sensitivity.

Timing, space and ADHD: the dopamine theory revisited

OBJECTIVE

The objective of this study was to review the dopamine theory of attention deficit hyperactivity disorder (ADHD) in terms of advances made over the last decade.

METHOD

'Hyper' and 'hypo' dopaminergic theories are discussed, as well as noradrenergic and neuropsychological findings in ADHD. A model incorporating both anterior and posterior attention systems, involved in orienting, inhibition, vigilance and working memory, is described. Neuropsychological studies of covert orienting are reviewed.

RESULTS

The dopamine theory is supported by neuroimaging, genetic and stimulant medication studies, which confirm an inhibitory dopaminergic effect at striatal/prefrontal level. Work in rodents and primates, as well as humans has shown that noradrenergic systems are also important in prefrontal regulation, in particular alpha(2A) noradrenergic agonists have a beneficial effect on cognitive tasks. Neuropsychological studies implicate posterior parietal mechanisms in the orienting of attention. Working memory may require integration of spatial and temporal information, involving anterior and posterior systems.

CONCLUSIONS

Anterior and posterior attention systems are involved in inhibition, working memory and orientation. Attention deficit hyperactivity disorder symptoms and subtypes are likely to reflect deficits in both inhibition and working memory, and may be heterogeneous. While the dopamine theory is supported by genetic and stimulant medication studies, the work of Arnsten and colleagues suggests a potential role for alpha(2) noradrenergic agonists such as guanfacine.

Clinical relevance of the primary findings of the MTA: success rates based on severity of ADHD and ODD symptoms at the end of treatment

OBJECTIVES

To develop a categorical outcome measure related to clinical decisions and to perform secondary analyses to supplement the primary analyses of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA).

METHOD

End-of-treatment status was summarized by averaging the parent and teacher ratings of attention-deficit/hyperactivity disorder and oppositional defiant disorder symptoms on the Swanson, Nolan, and Pelham, version IV (SNAP-IV) scale, and low symptom-severity ("Just a Little") on this continuous measure was set as a clinical cutoff to form a categorical outcome measure reflecting successful treatment. Three orthogonal comparisons of the treatment groups (combined treatment [Comb], medication management [MedMgt], behavioral treatment [Beh], and community comparison [CC]) evaluated hypotheses about the MTA medication algorithm ("Comb + MedMgt versus Beh + CC"), multimodality superiority ("Comb versus MedMgt"), and psychosocial substitution ("Beh versus CC").

RESULTS

The summary of SNAP-IV ratings across sources and domains increased the precision of measurement by 30%. The secondary analyses of group differences in success rates (Comb = 68%; MedMgt = 56%; Beh = 34%; CC = 25%) confirmed the large effect of the MTA medication algorithm and a smaller effect of multimodality superiority, which was now statistically significant (p < .05). The psychosocial substitution effect remained negligible and nonsignificant.

CONCLUSION

These secondary analyses confirm the primary findings and clarify clinical decisions about the choice between multimodal and unimodal treatment with medication.

Symptom profiles in children with ADHD: effects of comorbidity and gender

OBJECTIVE

To examine ratings and objective measures of attention-deficit/hyperactivity disorder (ADHD) symptoms to assess whether ADHD children with and without comorbid conditions have equally high levels of core symptoms and whether symptom profiles differ as a function of comorbidity and gender.

METHOD

Four hundred ninety-eight children from the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) were divided into comorbid groups based on the parent Diagnostic Interview Schedule for Children and assessed via parents' and teachers' Swanson, Nolan, and Pelham (SNAP) ratings and a continuous performance test (CPT). Comorbidity and gender effects were examined using analyses of covariance controlled for age and site.

RESULTS

CPT inattention, impulsivity, and dyscontrol errors were high in all ADHD groups. Children with ADHD + oppositional defiant or conduct disorder were rated as more impulsive than inattentive, while children with ADHD + anxiety disorders (ANX) were relatively more inattentive than impulsive. Girls were less impaired than boys on most ratings and several CPT indices, particularly impulsivity, and girls with ADHD + ANX made fewer CPT impulsivity errors than girls with ADHD-only.

CONCLUSIONS

Children with ADHD have high levels of core symptoms as measured by rating scales and CPT, irrespective of comorbidity. However, there are important differences in symptomatology as a function of comorbidity and gender.

Findings from the NIMH Multimodal Treatment Study of ADHD (MTA): implications and applications for primary care providers

In 1992, the National Institute of Mental Health and 6 teams of investigators began a multisite clinical trial, the Multimodal Treatment of Attention-Deficit Hyperactivity Disorder (MTA) study. Five hundred seventy-nine children were randomly assigned to either routine community care (CC) or one of three study-delivered treatments, all lasting 14 months. The three MTA treatments-monthly medication management (usually methylphenidate) following weekly titration (MedMgt), intensive behavioral treatment (Beh), and the combination (Comb)-were designed to reflect known best practices within each treatment approach. Children were assessed at four time points in multiple outcome. Results indicated that Comb and MedMgt interventions were substantially superior to Beh and CC interventions for attention-deficit hyperactivity disorder symptoms. For other functioning domains (social skills, academics, parent-child relations, oppositional behavior, anxiety/depression), results suggested slight advantages of Comb over single treatments (MedMgt, Beh) and community care. High quality medication treatment characterized by careful yet adequate dosing, three times daily methylphenidate administration, monthly follow-up visits, and communication with schools conveyed substantial benefits to those children that received it. In contrast to the overall study findings that showed the largest benefits for high quality medication management (regardless of whether given in the MedMgt or Comb group), secondary analyses revealed that Comb had a significant incremental effect over MedMgt (with a small effect size for this comparison) when categorical indicators of excellent response and when composite outcome measures were used. In addition, children with parent-defined comorbid anxiety disorders, particularly those with overlapping disruptive disorder comorbidities, showed preferential benefits to the Beh and Comb interventions. Parental attitudes and disciplinary practices appeared to mediate improved response to the Beh and Comb interventions.

Methylphenidate dosage for children with ADHD over time under controlled conditions: lessons from the MTA

OBJECTIVES

To examine the trajectory of methylphenidate (MPH) dosage over time, following a controlled titration, and to ascertain how accurately the titration was able to predict effective long-term treatment in children with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Using the 14-month-treatment database of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), the outcome of the initial placebo-controlled, double-blind, randomized daily switch titration of MPH was compared with the subsequent maintenance pharmacotherapy. Children received monthly monitoring visits and, when needed, medication adjustments.

RESULTS

Of the 198 children for whom MPH was the optimal treatment at titration (mean +/- SD dose: 30.5 +/- 14.2 mg/day), 88% were still taking MPH at the end of maintenance (mean dose 34.4 +/- 13.3 mg/day). Titration-determined dose and end-of-maintenance dose were significantly correlated (r = 0.52-0.68). Children receiving combined pharmacotherapy and behavioral treatment ended maintenance on a lower dose (31.1 +/- 11.7 mg/day) than did children receiving pharmacotherapy only (38.1 +/- 14.2 mg/day). Of the 230 children for whom titration identified an optimal treatment, 17% continued both the assigned medication and dosage throughout maintenance. The mean number of pharmacological changes per child was 2.8 +/- 1.8 (SD), and time to first change was 4.7 months +/- 0.3 (SE).

CONCLUSIONS

For most children, initial titration found a dose of MPH in the general range of the effective maintenance dose, but did not prevent the need for subsequent maintenance adjustments. For optimal pharmacological treatment of ADHD, both careful initial titration and ongoing medication management are needed.

ADHD comorbidity findings from the MTA study: comparing comorbid subgroups

OBJECTIVES

Previous research has been inconclusive whether attention-deficit/hyperactivity disorder (ADHD), when comorbid with disruptive disorders (oppositional defiant disorder [ODD] or conduct disorder [CD]), with the internalizing disorders (anxiety and/or depression), or with both, should constitute separate clinical entities. Determination of the clinical significance of potential ADHD + internalizing disorder or ADHD + ODD/CD syndromes could yield better diagnostic decision-making, treatment planning, and treatment outcomes.

METHOD

Drawing upon cross-sectional and longitudinal information from 579 children (aged 7-9.9 years) with ADHD participating in the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), investigators applied validational criteria to compare ADHD subjects with and without comorbid internalizing disorders and ODD/CD.

RESULTS

Substantial evidence of main effects of internalizing and externalizing comorbid disorders was found. Moderate evidence of interactions of parent-reported anxiety and ODD/CD status were noted on response to treatment, indicating that children with ADHD and anxiety disorders (but no ODD/CD) were likely to respond equally well to the MTA behavioral and medication treatments. Children with ADHD-only or ADHD with ODD/CD (but without anxiety disorders) responded best to MTA medication treatments (with or without behavioral treatments), while children with multiple comorbid disorders (anxiety and ODD/CD) responded optimally to combined (medication and behavioral) treatments.

CONCLUSIONS

Findings indicate that three clinical profiles, ADHD co-occurring with internalizing disorders (principally parent-reported anxiety disorders) absent any concurrent disruptive disorder (ADHD + ANX), ADHD co-occurring with ODD/CD but no anxiety (ADHD + ODD/CD), and ADHD with both anxiety and ODD/CD (ADHD + ANX + ODD/CD) may be sufficiently distinct to warrant classification as ADHD subtypes different from "pure" ADHD with neither comorbidity. Future clinical, etiological, and genetics research should explore the merits of these three ADHD classification options.

Impairment and deportment responses to different methylphenidate doses in children with ADHD: the MTA titration trial

OBJECTIVE

Results of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) were analyzed to determine whether a double-blind, placebo-controlled methylphenidate (MPH) titration trial identified the best MPH dose for each child with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Children with ADHD assigned to MTA medication treatment groups (n = 289) underwent a controlled 28-day titration protocol that administered different MPH doses (placebo, low, middle, and high) on successive days.

RESULTS

A repeated-measures analysis of variance revealed main effects for MPH dose with greater effects on teacher ratings of impairment and deportment (F3 = 100.6, n = 223, p = .0001; effect sizes 0.8-1.3) than on parent ratings of similar endpoints (F3 = 55.61, n = 253, p = .00001; effect sizes 0.4-0.6). Dose did not interact with period, dose order, comorbid diagnosis, site, or treatment group.

CONCLUSIONS

The MTA titration protocol validated the efficacy of weekend MPH dosing and established a total daily dose limit of 35 mg of MPH for children weighing less than 25 kg. It replicated previously reported MPH response rates (77%), distribution of best doses (10-50 mg/day) across subjects, effect sizes on impairment and deportment, as well as dose-related adverse events.

Multimodal treatment of ADHD in the MTA: an alternative outcome analysis

OBJECTIVE

To conduct a post hoc investigation of the utility of a single composite measure of treatment outcome for the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) at 14 months postbaseline.

BACKGROUND

Examination of multiple measures one at a time in the main MTA intent-to-treat outcome analyses failed to detect a statistically significant advantage of combined treatment (Comb) over medication management (MedMgt). A measure that increases power and precision using a single outcome score may be a useful alternative to multiple outcome measures.

METHOD

Factor analysis of baseline scores yielded two "source factors" (parent and teacher) and one "instrument factor" (parent-child interactions). A composite score was created from the average of standardized parent and teacher measures.

RESULTS

The composite was internally consistent (alpha = .83), reliable (test-retest over 3 months = 0.86), and correlated 0.61 with clinician global judgments. In an intent-to-treat analysis, Comb was statistically significantly better than all other treatments, with effect sizes ranging from small (0.28) versus MedMgt, to moderately large (0.70) versus a community comparison group.

CONCLUSIONS

A composite of ADHD variables may be an important tool in future treatment trials with ADHD and may avoid some of the statistical limitations of multiple measures.

Parent cognitions as predictors of child treatment response in attention-deficit/hyperactivity disorder

Using a subsample of 105 children and their parents (100 mothers, 57 fathers) from the Multimodal Treatment Study of Children with ADHD (the MTA), the value of parents' baseline cognitions as predictors of children's treatment outcome at 14 months was examined. Measures of parents' cognitions about themselves, their ADHD children, and their parenting, as well as a self-report measure of dysfunctional discipline were included. Both mothers' and fathers' self-reported use of dysfunctional discipline predicted worse child treatment outcome. Low self-esteem in mothers, low parenting efficacy in fathers, and fathers' attributions of noncompliance to their ADHD child's insufficient effort and bad mood also were associated with worse child treatment outcome. All of these predictive relations were obtained even after MTA treatment effects had been taken into account. Secondary analyses indicated that mothers had a more external locus of control, lower self-esteem, lower parenting efficacy, and a greater tendency to attribute noncompliance to their ADHD child's bad mood than did fathers.

Parenting and family stress treatment outcomes in attention deficit hyperactivity disorder (ADHD): an empirical analysis in the MTA study

Parenting and family stress treatment outcomes in the MTA study were examined. Male and female (579), 7-9-year-old children with combined type Attention Deficit Hyperactivity Disorder (ADHD), were recruited at six sites around the United States and Canada, and randomly assigned to one of four groups: intensive, multi-faceted behavior therapy program alone (Beh); carefully titrated and monitored medication management strategy alone (MedMgt); a well-integrated combination of the two (Comb); or a community comparison group (CC). Treatment occurred over 14 months, and assessments were taken at baseline, 3, 9, and 14 months. Parenting behavior and family stress were assessed using parent-report and child-report inventories. Results showed that Beh alone, MedMgt alone, and Comb produced significantly greater decreases in a parent-rated measure of negative parenting, Negative/Ineffective Discipline, than did standard community treatment. The three MTA treatments did not differ significantly from each other on this domain. No differences were noted among the four groups on positive parenting or on family stress variables. Results are discussed in terms of the theoretical and empirically documented importance of negative parenting in the symptoms, comorbidities and long-term outcomes of ADHD.

Familial aggregation of ADHD characteristics

Patterns of familial aggregation of ADHD symptoms in parents of ADHD and non-ADHD children were examined. Within the ADHD sample, symptom aggregation was examined as a function of biological relationship, parent and child gender, and children's comorbid diagnoses. Participants consisted of parents of 579 children with ADHD, Combined Type participating in the multimodal treatment study of children with ADHD and parents of 288 normal control participants. Adult symptoms of ADHD were measured by both self-report and report of a significant other. Results indicated that the parents of children with ADHD had higher ratings of inattention/cognitive problems, hyperactivity/restlessness, impulsivity/emotional lability, and lower self-concept than parents of children without ADHD on both self-report and other-report ratings. Within the ADHD sample of children, other-report ratings of inattention/cognitive problems and impulsivity/emotional lability were higher for biological parents compared to nonbiological parents whereas self-ratings were not related to biological status. These findings support previous research documenting familial aggregation of ADHD and appear to strengthen the hypothesis that there is a genetic contribution to ADHD.

Linkage of the dopamine D4 receptor gene and attention-deficit/hyperactivity disorder

OBJECTIVE

There is considerable evidence supporting a genetic component in the etiology of attention-deficit/hyperactivity disorder (ADHD). Because stimulant medications act primarily on the dopaminergic system, dopamine system genes are prime candidates for genetic susceptibility factors for ADHD. Previous studies by several groups have observed a significant association of ADHD and an allele with 7 copies of the 48 base pair repeat in the third exon of the dopamine D4 receptor.

METHOD

The authors sought to replicate these previous findings by collecting an independent sample of families from Toronto, Ontario, Canada, and confirming this finding in an expanded sample of ADHD families collected from Irvine, California. Using the transmission disequilibrium test (TDT), the authors tested for biased transmission of the 7-repeat allele at the exon III polymorphism of the dopamine D4 receptor locus in these samples of ADHD subjects.

RESULTS

Biased transmission of the 7-repeat allele from parents to ADHD probands and their affected siblings was observed in the 2 new samples of families collected in Toronto and Irvine (TDT chi2 = 2.711, 1 df, one-sided p value = .050) and for these samples combined with the 52 families previously reported from Irvine (TDT chi2 = 6.426, 1 df, one-sided p value = .006).

CONCLUSIONS

The results of this study further support the possibility of a role of the dopamine D4 receptor locus in ADHD.

Anxiety as a predictor and outcome variable in the multimodal treatment study of children with ADHD (MTA)

Initial moderator analyses in the Multimodal Treatment Study of Children with ADHD (MTA) suggested that child anxiety ascertained by parent report on the Diagnostic Interview Schedule for Children 2.3 (DISC Anxiety) differentially moderated the outcome of treatment. Left unanswered were questions regarding the nature of DISC Anxiety, the impact of comorbid conduct problems on the moderating effect of DISC Anxiety, and the clinical significance of DISC Anxiety as a moderator of treatment outcome. Thirty-three percent of MTA subjects met DSM-III-R criteria for an anxiety disorder excluding simple phobias. Of these, two-thirds also met DSM-III-R criteria for comorbid oppositional-defiant or conduct disorder whereas one-third did not, yielding an odds ratio of approximately two for DISC Anxiety, given conduct problems. In this context, exploratory analyses of baseline data suggest that DISC Anxiety may reflect parental attributions regarding child negative affectivity and associated behavior problems (unlike fearfulness), particularly in the area of social interactions, another core component of anxiety that is more typically associated with phobic symptoms. Analyses using hierarchical linear modeling (HLM) indicate that the moderating effect of DISC Anxiety continues to favor the inclusion of psychosocial treatment for anxious ADHD children irrespective of the presence or absence of comorbid conduct problems. This effect, which is clinically meaningful, is confined primarily to parent-reported outcomes involving disruptive behavior, internalizing symptoms, and inattention; and is generally stronger for combined than unimodal treatment. Contravening earlier studies, no adverse effect of anxiety on medication response for core ADHD or other outcomes in anxious or nonanxious ADHD children was demonstrated. When treating ADHD, it is important to search for comorbid anxiety and negative affectivity and to adjust treatment strategies accordingly.

Family processes and treatment outcome in the MTA: negative/ineffective parenting practices in relation to multimodal treatment

To elucidate processes underlying therapeutic change in a large-scale randomized clinical trial, we examined whether alterations in self-reported parenting practices were associated with the effects of behavioral, medication, or combination treatments on teacher-reported outcomes (disruptive behavior, social skills, internalizing symptoms) in children with attention-deficit hyperactivity disorder (ADHD). Participants were 579 children with Combined-type ADHD, aged 7-9.9 years, in the Multimodal Treatment Study of Children with ADHD (MTA). We uncovered 2 second-order factors of parenting practices, entitled Positive Involvement and Negative/Ineffective Discipline. Although Positive Involvement was not associated with amelioration of the school-based outcome measures, reductions in Negative/Ineffective Discipline mediated improvement in children's social skills at school. For families showing the greatest reductions in Negative/Ineffective Discipline, effects of combined medication plus behavioral treatment were pronounced in relation to regular community care. Furthermore, only in combination treatment (and not in behavioral treatment alone) was decreased Negative/Ineffective Discipline associated with reduction in children's disruptive behavior at school. Here, children in families receiving combination treatment who showed the greatest reductions in Negative/Ineffective Discipline had teacher-reported disruptive behavior that was essentially normalized. Overall, the success of combination treatment for important school-related outcomes appears related to reductions in negative and ineffective parenting practices at home; we discuss problems in interpreting the temporal sequencing of such process-outcome linkages and the means by which multimodal treatment may be mediated by psychosocial processes related to parenting.

Psychosocial treatment strategies in the MTA study: rationale, methods, and critical issues in design and implementation

The Collaborative Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder (ADHD), the MTA, is the first multisite, cooperative agreement treatment study of children, and the largest psychiatric/psychological treatment trial ever conducted by the National Institute of Mental Health. It examines the effectiveness of Medication vs. Psychosocial treatment vs. their combination for treatment of ADHD and compares these experimental arms to each other and to routine community care. In a parallel group design, 579 (male and female) ADHD children, aged 7-9 years, 11 months, were randomly assigned to one of the four experimental arms, and then received 14 months of prescribed treatment (or community care) with periodic reassessments. After delineating the theoretical and empirical rationales for Psychosocial treatment of ADHD, we describe the MTA's Psychosocial Treatment strategy applied to all children in two of the four experimental arms (Psychosocial treatment alone; Combined treatment). Psychosocial treatment consisted of three major components: a Parent Training component, a two-part School Intervention component, and a child treatment component anchored in an intensive Summer Treatment Program. Components were selected based on evidence of treatment efficacy and because they address comprehensive symptom targets, settings, comorbidities, and functional domains. We delineate key conceptual and logistical issues faced by clinical researchers in design and implementation of Psychosocial research with examples of how these issues were addressed in the MTA study.

Behavioral versus behavioral and pharmacological treatment in ADHD children attending a summer treatment program

As part of the behavioral treatment in the Multimodal Treatment Study of Children with ADHD (MTA9), children participated in an intensive summer treatment program (STP). This study examined the differences between 57 children in the combined treatment (Comb) group, who were medicated, and 60 children in the behavioral treatment (Beh) group, who were unmedicated throughout the STP. Comb children were significantly better than Beh on 5 measures: rule following, good sportsmanship, peer negative nominations, and STP teacher posttreatment ratings of inattention/overactivity. Groups did not differ on any of the other 30 measures, and responded similarly to the STP over time. Comparisons to normative data revealed that Comb children were more likely to fall within the normative range on 6 measures. The differences between these results and the main MTA results, in which Comb was always superior to Beh, are discussed in terms of the relative intensity of combined treatments. The implications for future studies of pharmacological and behavioral treatment for ADHD are discussed.

Attention deficit/hyperactivity disorder: characteristics, interventions and models

An epidemiological study of Attention Deficit/Hyperactivity Disorder (ADHD) suggests that the prevalence may be two to three times higher than the figure of 3-5% often cited. In addition, the data suggest that both underdiagnosis and overdiagnosis occur frequently. Rodent animal models of ADHD, like the Spontaneously Hypertensive Rat (SHR) and other rat models such as those with chemical and radiation-induced brain lesions and cerebellar stunting, and the Coloboma mouse model exhibit clear similarities with several aspects of the human disorder and should prove useful in studying specific traits. Operant behavioral tasks that model learning, short-term memory and simple discriminations are sensitive to ADHD and methylphenidate has been shown to normalize ADHD performance in a short-term memory task. Recent findings challenge not only the current postulate that response inhibition is a unique deficit in ADHD, but also the concepts of ADHD and its treatment, which presume intact perceptual abilities. Time perception deficits may account, in part, for the excessive variability in motor response times on speeded reaction time tasks, motor control problems and motor clumsiness associated with ADHD. The Multimodality Treatment Study of ADHD (MTA) provided data suggesting that pharmacological interventions that included systematic and frequent follow-up with parents and teachers, with or without psychosocial interventions, are superior to psychosocial interventions or standard community care alone. Additionally, the MTA was one of the first studies to demonstrate benefits of multimodal and pharmacological interventions lasting longer than 1 year. Imaging studies have demonstrated differences in brain areas in children with ADHD: anterior corpus callosum, right anterior white matter, and cerebellar volumes are all decreased in children with ADHD and there is less brain asymmetry in ADHD subjects. Additionally, functional imaging studies, coupled with pharmacological manipulations, suggest decreased blood flow and energy utilization in prefrontal cortex and striatum and the dysregulation of catecholamine systems in persons with ADHD.

The Texas Children's Medication Algorithm Project: Report of the Texas Consensus Conference Panel on Medication Treatment of Childhood Attention-Deficit/Hyperactivity Disorder. Part I. Attention-Deficit/Hyperactivity Disorder

OBJECTIVES

Expert consensus methodology was used to develop evidence-based, consensually agreed-upon medication treatment algorithms for attention-deficit/hyperactivity disorder (ADHD) in the public mental health sector. Although treatment algorithms for adult mental disorders have been developed, this represents one of the first attempts to develop similar algorithms for childhood mental disorders. Although these algorithms were developed initially for the public sector, the goals of this approach are to increase the uniformity of treatment and improve the clinical outcomes of children and adolescents with ADHD in a variety of treatment settings.

METHOD

A consensus conference of academic clinicians and researchers, practicing clinicians, administrators, consumers, and families was convened to develop evidence-based consensus algorithms for the pharmacotherapy of childhood ADHD. After a series of presentations of current research evidence and panel discussion, the consensus panel met and drafted the algorithms along with guidelines for implementation.

RESULTS

The panel developed consensually agreed-upon algorithms for ADHD with and without specific comorbid disorders. The algorithms consist of systematic strategies for psychopharmacological interventions and tactics to ensure successful implementation of the strategies. While the algorithms focused on the medication management of ADHD, the conference emphasized that psychosocial treatments are often a critical component of the overall management of ADHD.

CONCLUSIONS

Medication algorithms for ADHD can be developed with consensus. A companion article will discuss the implementation of these algorithms.