Effects of methylphenidate on complex cognitive processing in attention-deficit hyperactivity disorder

Three experiments were conducted to explore the effects of methylphenidate (MPH), attention-deficit hyperactivity disorder (ADHD) diagnosis, and age on performance on a complex visual-memory search task. Results showed that the effects of MPH varied with information load. On low-processing loads, all doses of MPH helped children with ADHD to improve accuracy with no cost to reaction time (RT), whereas on high loads, higher MPH doses improved error rates while slowing RT. Without medication, children with ADHD showed high error rates and slow RTs across both low and high loads, as did younger, normal control children. Because MPH slowed performance on only the most difficult, high-load conditions, it is argued that the drug improves self-regulatory ability, enabling children with ADHD to adapt differentially to high and low loads.     

Parenting in mothers with and without attention-deficit/hyperactivity disorder

The authors examined the impact of maternal attention-deficit/hyperactivity disorder (ADHD) on parenting behaviors. Sixty mothers between the ages of 31 and 50 with (n = 30) and without (n = 30) ADHD and their 8- to 14-year-old children with ADHD completed self-report and laboratory measures of monitoring of child behavior, consistency in parenting, and parenting problem-solving abilities. These parenting behaviors were selected because of their established links to the development of child behavior problems. As predicted, mothers with ADHD were found to be poorer at monitoring child behavior and less consistent disciplinarians compared with mothers without ADHD. There was some evidence to support the prediction that mothers with ADHD were less effective at problem solving about childrearing issues than control mothers. The differences between the 2 groups of mothers persisted after child oppositional and conduct-disordered behavior were controlled. These results indicate that parenting is an area of functioning that requires more attention in adult ADHD research.     

Trait mechanisms in youth with and without attention-deficit/hyperactivity disorder

Relations of temperament and personality traits within children and adolescents with ADHD and non-ADHD controls were examined. A two-process structure was hypothesized involving top-down effortful and bottom-up reactive response tendencies. Top-down processes were hypothesized to relate to inattentive ADHD symptoms, whereas bottom-up processes were hypothesized to relate to hyperactive–impulsive ADHD symptoms. Each hypothesis was tested in a sample of 179 children age 7–13 (113 boys; 107 ADHD) and then replicated in 184 adolescents age 14–17 (109 boys; 87 ADHD). All families completed a multistage diagnostic process. Youth completed laboratory measures of cognitive control, and parents completed trait ratings. Traits examined in the current study included effortful control, reactive control, resiliency, negative emotionality, neuroticism, extraversion, openness, agreeableness, and conscientiousness. Correlational relations among traits were inconclusive, but external correlations with cognitive tasks and ADHD symptoms were interpretable within the hypothesized two-process framework. Results provide partial support for a distinction between effortful and reactive traits and suggest this distinction is useful in relation to understanding ADHD.     

Patterns of friendship among girls with and without attention-deficit/hyperactivity disorder

Examined patterns of friendship participation, stability, and quality among previously unfamiliar, ethnically diverse girls with attention-deficit/hyperactivity disorder (ADHD; n = 140) and comparison (n = 88) girls, aged 6–12 years, who attended 5-week naturalistic summer camps. Each girl completed sociometric nominations during Weeks 1, 3, and 5 of the camps; friendships were indexed by examining patterns of reciprocal nominations. At each assessment point, girls with ADHD had fewer mutual friends and were more likely to have no friends. Girls with Combined-type ADHD exhibited difficulties maintaining friendships from the beginning to middle of camp, whereas girls with Inattentive-type ADHD demonstrated poor friendship stability from the middle to end of camp. In general, girls with ADHD had higher levels of negative relationship features—including conflict and relational aggression—than did comparison girls, but levels of positive relationship features did not differ across subgroups. Friendship status predicted positive and negative peer regard, controlling for Verbal IQ and diagnostic status. Overall, although girls with ADHD were able to make friends to some extent, they differed from comparison girls in terms of the likelihood of doing so, the ability to maintain the friendships that they did form, and the levels of negative features found in their friendships.     

Effects of background anger,provocation, and methylphenidate on emotional arousal and aggressive responding in attention-deficit hyperactivity disordered boys with and without concurrent aggressiveness

We investigated the effects of background anger, provocation, and methylphenidate on emotional, physiological, and behavioral responding in children with attentiondeficit hyperactivity disorder (ADHD) with and without concurrent aggression. Our study revealed that ADHD boys showed more emotional and physiological distress when exposed to an interaction in which an administrator chastised each boy's favorite counselor, compared to a friendly interaction between the two adults. The background anger manipulation did not affect the aggressive behavior of the boys against an opponent in an aggressive game. High-aggressive (HA) ADHD boys were more likely to respond to provocation with aggression than low-aggressive (LA) ADHD boys, but only LA boys showed increased physiological reactivity with increasing provocation. Methylphenidate resulted in increased heart rates under all conditions and did not interact with any of the other findings.This project was conducted while the first author had the support of National Institute of Alcohol Abuse and Alcoholism grant AA 06267.The authors wish to thank the staff members of the 1987 Summer Day Treatment Program who assisted in conducting this project. The authors also express their appreciation to Karen Guthrie for coordinating the medication assessment and to Hart Blanton for computer programming.     

Non-stimulant treatment of attention-deficit/hyperactivity disorder

Stimulants are a highly efficacious and safe treatment for attention-deficit/hyperactivity disorder (ADHD), with 75% to 90% of patients responding well if two different stimulants (amphetamine and methylphenidate) are used. Nonetheless, a subset of ADHD patients will either fail to respond to stimulants or have side effects that preclude their use (tics, severe loss of appetite, marked insomnia). For such patients, there are a number of non-stimulant agents that serve as second-line treatments. Tricyclic antidepressants (TCAs) are the most studied of these drugs. They are superior to placebo in the treatment of ADHD and may reduce abnormal movements in patients with ADHD/tic disorder. TCAs often produce side effects of sedation, dry mouth, and constipation. Bupropion is superior to placebo in the treatment of ADHD and has a more favorable side-effect profile than the TCAs. A new selective norepinephrine reuptake inhibitor, atomoxetine, has been shown to be efficacious in the treatment of ADHD and has recently received an approvable letter from the Food and Drug Administration. The a-agonists clonidine and guanfacine have also been used as alternative agents in ADHD, though the controlled data are more limited. A recent controlled clinical trial suggests a combination of methylphenidate and clonidine has advantages in the treatment of comorbid ADHD and tics over either medication alone. Clinical guidelines for each of these agents, as well as their use in combination with stimulants in comorbid conditions, will be discussed.     

A psychoanalytic perspective on attention-deficit/hyperactivity disorder

Psychoanalysts have tended to view the diagnosis of AD/HD either with skepticism or as a contraindication to analytic treatment. The author reviews the history of this puzzling diagnostic entity, which is estimated to account for up to fifty percent of child referrals, and suggests that a psychoanalytic perspective on the underlying disturbance in ego functioning helps to clarify the nature of the symptom picture. Whatever the etiology, which may be compound, she suggests that psychoanalytic treatment, most often in conjunction with psychopharmacological therapy, can address the core disturbance in ego integration that creates the familiar triad of inattention, impulsivity, and hyperactivity.     

School-based intervention for adolescents with attention-deficit/hyperactivity disorder: Effects on academic functioning

Multi-component training interventions such as the Challenging Horizons Program (CHP) improve organization skills and academic functioning of middle school students with attention-deficit/hyperactivity disorder (ADHD); however, few studies have investigated treatment for high school students. We explored the extent to which CHP adapted for high school would improve proximal (e.g., organization skills, homework performance) and distal (e.g., report card grades) academic outcomes through 6-month follow-up relative to a community care (CC) condition. Participants included 186 adolescents who were randomly assigned to CHP (n = 92; 80% male; M age = 15.0; SD = 0.8) or CC (n = 94; 78% male; M age = 15.1; SD = 0.9) with CHP delivered over one school year. Parent, teacher, and self-report ratings of organization skills and academic performance, report card grades, and achievement tests were collected across multiple occasions. Intent-to-treat analyses using hierarchical linear modeling revealed significant improvements of small to medium magnitude (d range = 0.32 to 0.58) for parent-rated organization skills, homework performance, and academic functioning at 6-month follow-up. CHP effect on grades was small, but associated with a less steep decline than that found for CC. No statistically significant effects on teacher or self-report ratings were obtained. CHP appears efficacious for ameliorating organization skills and homework performance deficits exhibited by high school students with ADHD and can protect against decline in report card grades experienced by these students. CHP may require supplementation with academic skills instruction for some students and may need implementation beyond one school year to produce durable effects.     

Neurocognitive functioning in adults with attention-deficit/hyperactivity disorder

The performance of nine adults with attention-deficit/hyperactivity disorder (ADHD) was compared with the performance of 23 normal controls on computerized measures of target orientation, sustained attention, encoding speed, and motor output/response organization to determine the nature of the neurocognitive deficits of adults with ADHD. While the groups' performances on measures of sustained attention and encoding speed did not differ, significant group differences were seen on a task that targeted motor output/response organization. These data suggest that the neurocognitive difficulties of ADHD adults are not related to a primary deficit in sustained attentional functioning. Rather, the deficient information processing in ADHD adults is related to difficulties with motor output/response organization.     

Gait control in children with attention-deficit/hyperactivity disorder

The current profile of gait control in children with ADHD is incomplete and predominately based on children walking forward at a self-selected pace. There are no studies of potential gait deficits in this clinical population when walking in different directions in combination with varying rates of stepping that are freely selected and entrained to an external stimulus. The purpose of the current study was to address this lack of information by assessing gait of children aged 7–17 years with (n = 17) and without (n = 26) ADHD. Participants walked forward and backward along an electronically instrumented carpet at a self-selected stepping rate and in synchrony to a metronome that dictated an increased and decreased stepping rate. Using repeated measures analysis of covariance (ANCOVA) to assess spatiotemporal gait parameters, results showed that children with ADHD exhibited a significantly exaggerated, toes ‘turned out,’ foot position for all walking conditions compared to typically developing children. When walking backward, children with ADHD produced an increased step width, higher stepping cadence, and increased velocity. Additionally, coefficient of variation ratios indicated that children with ADHD produced greater variability of velocity, cadence, and step time for all walking conditions, and greater variability for stride length when walking at an increased stepping rate. Results were interpreted in terms of clinical significance and practical ramifications that inform rehabilitation specialists in designing therapies that ameliorate the reported gait deficits.     

Single and combined effects of methylphenidate and behavior therapy on the classroom performance of children with attention-deficit hyperactivity disorder

Twenty-four boys with attention deficit-hyperactivity disorder (ADHD) participating in an intensive summer treatment program each received b.i.d. placebo and two doses of methylphenidate (MPH, 0.3 mg/kg and 0.6 mg/kg) crossed with two classroom settings: a behavior modification classroom including a token economy system, time out and daily home report card, and a regular classroom setting not using these procedures. Dependent variables included classroom observations of on-task and disruptive behavior, academic work completion and accuracy, and daily self-ratings of performance. Both MPH and behavior modification alone significantly improved children's classroom behavior, but only MPH improved children's academic productivity and accuracy. Singly, behavior therapy and 0.3 mg/kg PMH produced roughly equivalent improvements in classroom behavior. Further, the combination of behavior therapy and 0.3 mg/kg MPH resulted in maximal behavioral improvements, which were nearly identical to those obtained with 0.6 mg/kg MPH alone.The authors gratefully acknowledge the assistance of Patricia Donovan, Michelle Berry, Mary Ingram, Patricia Wells, Beth Gnagy, Karen Greenslade, Mary Hamilton, and the entire staff of the Western Psychiatric Institute and Clinic ADHD Summer Treatment Program.     

Implicit sequence learning in young people with Tourette syndrome with and without co-occurring attention-deficit/hyperactivity disorder

Impaired habit-learning has been proposed to underlie the tic symptoms of Tourette syndrome (TS). However, accounts differ in terms of how habit-learning is altered in TS, with some authors proposing habit formation is impaired due to a deficient ‘chunking’ mechanism, and others proposing habit-learning is overactive and tics reflect hyperlearned behaviours. Attention-deficit/hyperactivity disorder (ADHD) frequently co-occurs with TS and is known to affect cognitive function in young people with co-occurring TS and ADHD (TS + ADHD). It is unclear, however, how co-occurring ADHD symptoms affect habit-learning in TS. In this study, we investigated whether young people with TS would show deficient or hyperactive habit-learning, and assessed the effects of co-occurring ADHD symptoms on habit-learning in TS. Participants aged 9–17 years with TS (n = 18), TS + ADHD (n = 17), ADHD (n = 13), and typical development (n = 20) completed a motor sequence learning task to assess habit-learning. We used a 2 (TS-yes, TS-no) × 2 (ADHD-yes, ADHD-no) factorial analysis to test the effects of TS, ADHD, and their interaction on accuracy and reaction time indices of sequence learning. TS was associated with intact sequence learning, but a tendency for difficulty transitioning from sequenced to non-sequenced performance was suggestive of hyper-learning. ADHD was associated with significantly poorer accuracy during acquisition of the sequence, indicative of impaired habit-learning. There were no interactions between the TS and ADHD factors, indicating young people with TS + ADHD showed both TS- and ADHD-related atypicalities in habit-learning.     

Eating pathology among adolescent girls with attention-deficit/hyperactivity disorder

The authors investigated prospectively assessed eating pathology (body image dissatisfaction and bulimia nervosa symptoms) among an ethnically and socioeconomically diverse sample of adolescent girls with attention-deficit/hyperactivity disorder-combined type (ADHD-C; n=93), ADHD-inattentive type (ADHD-I; n=47), and a comparison group (n=88). The sample, initially ages 6-12 years, participated in a 5-year longitudinal study (92% retention rate). After statistical control of relevant covariates, girls with ADHD-C at baseline showed more eating pathology at follow-up than did comparison girls; girls with ADHD-I were intermediate between these two groups. Baseline impulsivity symptoms, as opposed to hyperactivity and inattention, best predicted adolescent eating pathology. With statistical control of ADHD, baseline peer rejection and parent- child relationship problems also predicted adolescent eating pathology. The association between punitive parenting in childhood and pathological eating behaviors in adolescence was stronger for girls with ADHD than for comparison girls. Results are discussed in terms of the expansion of longitudinal research on ADHD to include female-relevant domains of impairment, such as eating pathology.     

Stimulus-dependent dopamine release in attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is related to an attenuated and dysfunctional dopamine system. Normally, a high extracellular dopamine level yields a tonic dopaminergic input that down-regulates stimuli-evoked phasic dopamine responses through autoreceptors. Abnormally low tonic extracellular dopamine in ADHD up-regulates the autoreceptors so that stimuli-evoked phasic dopamine is boosted. The authors propose that these boosted phasic responses yield hypersensitivity to environmental stimuli in ADHD. Stimuli evoking moderate brain arousal lead to well-functioning performance, whereas either too little or too much stimuli attenuate cognitive performance. Strong, salient stimuli may easily disrupt attention, whereas an environment with impoverished stimuli causes low arousal, which is typically compensated for by hyperactivity. Stochastic resonance is the phenomenon that makes a moderate noise facilitate stimulus discrimination and cognitive performance. Computational modeling shows that more noise is required for stochastic resonance to occur in dopamine-deprived neural systems in ADHD. This prediction is supported by empirical data.     

Predictors of physical aggression in children with attention-deficit/hyperactivity disorder

The present investigation examined factors that predict physical aggression in children with attention-deficit/hyperactivity disorder (ADHD). Stepwise, multiple regression-analyses were used to examine predictors of children's physical aggression as rated by parents at a 1-year follow-up point and by teachers at both 1- and 2-year follow-up points. Early parent and teacher ratings of verbal aggression (ie, cursing, teasing, and threatening) accounted for the greatest proportion of the variance in physical aggression ratings obtained at follow-up. None of the other predictor variables, including early ratings of physical aggression and ADHD behaviors, contributed significant additional variance beyond that accounted for by early verbal aggression ratings. Temporal and cross-informant analyses revealed that the relationship between verbal aggression and later physical aggression was situation-specific for teacher ratings but not parent ratings. Although physical aggression may emerge early in development, these data suggest that verbal aggression represents a stable, temperamental characteristic that may be of greater value than early physical aggression for predicting later physically aggressive acts.     

The predominantly inattentive subtype of attention-deficit/hyperactivity disorder

The predominantly inattentive (IN) subtype of attention-deficit/hyperactivity disorder (ADHD) is a recently defined condition that is often overlooked by professionals and is still not completely understood. Characterized by symptoms of inattentiveness, such as distractibility, failure to complete work, forgetfulness, and disorganization, the IN subtype differs from the more commonly recognized combined (CB) subtype of ADHD in that symptoms of hyperactivity and impulsivity are absent or minimal. Large-scale epidemiologic studies suggest that the IN subtype is at least as prevalent as the CB subtype, and is at least as likely to be associated with academic and/or social impairment. Diagnosis of the IN subtype, however, may be more challenging because in addition to inattentiveness, other symptoms, including learning problems, depression, and anxiety, may also present without externalizing behaviors. Several studies have shown that compared with the CB subtype, the IN subtype has a later age of onset and referral, a relatively larger proportion of affected females, and is much less likely to be associated with symptoms of oppositional defiant disorder or conduct disorder. Research is currently under way to examine the cognitive characteristics of the IN subtype and its genetic and neurobiologic underpinnings, as well as to evaluate the effectiveness of pharmacotherapy and other treatments.