Effects of methylphenidate on discounting of delayed rewards in attention deficit/hyperactivity disorder.

Impulsivity is a central component of attention deficit/hyperactivity disorder (ADHD). Delay discounting, or a preference for smaller, immediate rewards over larger, delayed rewards, is considered an important aspect of impulsivity, and delay-related impulsivity has been emphasized in etiological models of ADHD. In this study, we examined whether stimulant medication, an effective treatment for ADHD, reduced discounting of delayed experiential and hypothetical rewards among 49 children (ages 9–12 years) with ADHD. After a practice day, participants completed a 3-day double-blind placebo-controlled acute medication assessment. Active doses were long-acting methylphenidate (Concerta), with the nearest equivalents of 0.3 and 0.6 mg/kg TID immediate-release methylphenidate. On each testing day, participants completed experiential (real-world money in real time) and hypothetical discounting tasks. Relative to placebo, methylphenidate reduced discounting of delayed experiential rewards but not hypothetical rewards. Broadly consistent with etiological models that emphasize delay-related impulsivity among children with ADHD, these findings provide initial evidence that stimulant medication reduces delay discounting among those with the disorder. The results also draw attention to task parameters that may influence the sensitivity of various delay discounting measures to medication effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intellectual performance and school failure in children with attention deficit hyperactivity disorder and in their siblings.

Made psychiatric and intellectual assessments of 140 children with attention deficit hyperactivity disorder (ADHD), 120 normal controls, and their 303 siblings. The index children were White, non-Hispanic boys. ADHD children were more likely to have had learning disabilities, repeated grades, been placed in special classes, and received academic tutoring. They also did worse on the Wechsler Intelligence Scale for Children—Revised (WISC—R). Among ADHD probands, comorbid conduct, major depressive, and anxiety disorders predicted school placement more than school failure or WISC—R scores. However, the neuropsychological disability of all ADHD children could not be attributed to comorbid disorders because those without comorbidity had more school failure and lower WISC—R scores than normal controls. Intellectual impairment was also increased among siblings of ADHD children. This provides converging evidence that the ADHD syndrome is familial. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic heterogeneity in attention-deficit hyperactivity disorder (ADHD): Gender, psychiatric comorbidity, and maternal ADHD.

The authors examined the siblings of 140 attention-deficit hyperactivity disorder (ADHD) and 120 control probands and classified families as antisocial if the proband had conduct disorder or a parent had antisocial personality. Partial support was found for the hypothesis that the ADHD gender effect would be limited to antisocial families. Boys had an increased risk for ADHD compared with girls, but only among siblings from antisocial families. The effect size for predicting ADHD in siblings of probands was greater for maternal compared with paternal ADHD, but only for families exhibiting antisocial disorders. Strong support was found for the hypothesis that, compared with siblings from nonantisocial families, those from antisocial families would have more psychopathology (ADHD, depression, substance use, and conduct disorders). The presence of antisocial disorders signals a distinct subtype of ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-administered cocaine causes long-lasting increases in impulsive choice in a delay discounting task.

Cocaine use is associated with high levels of impulsive choice (preference for immediate over delayed rewards), but it is not clear whether cocaine use causes elevated impulsive choice, or whether elevated impulsive choice is solely a predisposing factor for cocaine use. This study examined the effects of prior cocaine self-administration on rats performing a delay discounting task commonly used to measure impulsive choice. Male Long-Evans rats were implanted with intravenous catheters, and following recovery, were trained to self-administer 30 mg/kg/day cocaine HCl (approx. 0.5 mg/kg/infusion) for 14 consecutive days (a control group received yoked intravenous saline infusions). Following three weeks of withdrawal, all rats were food-restricted and began training on the delay discounting task in standard operant chambers. On each trial, rats were given a choice between two levers. A press on one lever delivered a small food reward immediately, and a press on the other delivered a large food reward after a variable delay period. Rats that self-administered cocaine displayed greater impulsive choice (enhanced preference for the small immediate over the large delayed reward, as reflected by shorter indifference points) compared to controls, but were no different from controls on a “probabilistic discounting” task in which they chose between small certain and large uncertain rewards. These data suggest that self-administered cocaine can cause lasting elevations in impulsive choice, and that the high levels of impulsive choice observed in human cocaine users may be due in part to long-term effects of cocaine on brain function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological functioning in nonreferred siblings of children with attention deficit/hyperactivity disorder.

The goal of this study was to assess neuropsychological functioning in nonreferred siblings of children with attention deficit/hyperactivity disorder (ADHD). Participants were 156 siblings of ADHD probands with (N?=?40) and without (N?=?116) ADHD (according to criteria of the Diagnostic and Statistical Manual of Mental Disorders [3rd edition, revised; American Psychiatric Association, 1987]) and 118 siblings of non-ADHD normal controls of similar age, IQ, and grade level. Information on attention, executive, and memory functions was obtained in a standardized manner without knowledge of clinical status. Compared with siblings of controls, siblings with ADHD were significantly impaired on the Stroop test and on verbal learning and memory. In contrast, siblings without ADHD were similar to controls on virtually all measures. These data suggest that some executive, attention, and verbal learning deficits are found in nonreferred individuals with ADHD but that neuropsychological deficits are unlikely to constitute an endophenotype to ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls.

Fifty-six heroin addicts and 60 age-matched controls were offered choices between monetary rewards ($11–$80) available immediately and larger rewards ($25–$85) available after delays ranging from 1 week to 6 months. Participants had a 1-in-6 chance of winning a reward that they chose on one randomly selected trial. Delay-discounting rates were estimated from the pattern of participants' choices. The discounting model of impulsiveness (G. Ainslie, 1975) implies that delay-discounting rates are positively correlated with impulsiveness. On average, heroin addicts' discount rates were twice those of controls (p?=?.004), and discount rates were positively correlated with impulsivity as measured by self-report questionnaires (p?     

Exposure to rewards and the delay of gratification.

Gave 111 children aged 6, 7, 8, and 9 yrs old a choice between an immediate reward and a larger, delayed reward. Half of the Ss in each age group saw the rewards before choosing, while the other half did not. Exposure to the rewards led to more choices of delayed reward for 7 yr olds. The 6 yr olds predominantly chose immediate rewards regardless of exposure, while the 8 and 9 yr olds predominantly chose the delayed reward regardless of exposure. 2 explanations are offered for the results for the 7 yr olds. In one, the results are attributed to the effect of exposure on value and/or expectancy of the delayed reward. In the other, it is suggested that exposure orients attention to the value, rather than the immediacy, of the alternatives. In this view, delay of gratification in young children reflects a form of decentration. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associations between ADHD and psychoactive substance use disorders. Findings from a longitudinal study of high-risk siblings of ADHD children

This article investigates the relationship between attention-deficit/hyperactivity disorder (ADHD) and psychoactive substance use disorders (PSUD) in siblings of ADHD and normal-control probands and addresses issues of psychiatric comorbidity and gender. Using DSM-III-R structured diagnostic interviews and blind raters, the authors conducted a 4-year follow-up of siblings. ADHD and male gender predicted higher rates and an earlier onset of PSUD after adjusting for high-risk status, other psychiatric disorders, and age. Risk was particularly high if the siblings had ADHD plus conduct disorder. This study's findings confirms the authors' prior report high-lighting the importance of drug and alcohol prevention and cessation programs aimed at ADHD youth and their siblings, particularly those with comorbid conduct disorder.     

Disinhibitory psychopathology in male adolescents: Discriminating conduct disorder from attention-deficit/hyperactivity disorder through concurrent assessment of multiple autonomic states.

T. P. Beauchaine (2001) recently proposed a model of autonomic nervous system functioning that predicts divergent patterns of psychophysiological responding across disorders of disinhibition. This model was tested by comparing groups of male adolescents with attention-deficit/hyperactivity disorder (ADHD) and attention-deficit/hyperactivity disorder plus conduct disorder (CD/ADHD) with controls while performing a repetitive motor task in which rewards were administered and removed across trials. Participants then watched a videotaped peer conflict. Electrodermal responding (EDR), cardiac pre-ejection period (PEP), and respiratory sinus arrhythmia (RSA) were monitored. Compared with controls, the ADHD and CD/ADHD participants exhibited reduced EDR. The CD/ADHD group was differentiated from the ADHD and control groups on PEP and from the control group on RSA. Findings are discussed in terms of the motivational and regulational systems indexed. Implications for understanding rates of comorbidity between CD and ADHD are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluating the Endophenotype Model of ADHD Neuropsychological Deficit: Results for Parents and Siblings of Children With ADHD Combined and Inattentive Subtypes.

Neurogenetic models predict neuropsychological weaknesses in the relatives of children with attention-deficit/ hyperactivity disorder (ADHD). The authors examined executive and regulatory measures in 386 relatives (307 parents, 79 siblings) of children with ADHD combined type, ADHD inattentive type, and controls. Predicted deficits were seen on trailmaking (relatives of ADHD combined type only), stop-signal reaction times (relatives of girls only), and response variability (mothers only) but not on naming or output speed. Effects generally held, even with relatives' ADHD status controlled. A neuropsychologically impaired subgroup of children with ADHD had relatives with clear neuropsychological weaknesses. The authors conclude that a neurogenetic model of ADHD etiology is supportable only for a subset of executive functions and that neuropsychological heterogeneity warrants more examination in ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A prospective four-year follow-up study of children at risk for ADHD: psychiatric, neuropsychological, and psychosocial outcome

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is a familial disorder that places the siblings of ADHD children at high risk for ADHD, conduct, mood, and anxiety disorders. Although the pattern of psychiatric risk has been well documented by prior family studies, neither the short- nor long-term outcome of these high-risk siblings has been prospectively examined. OBJECTIVE: To document the 4-year psychiatric, psychosocial, and neuropsychological outcome of the siblings of children with ADHD. METHOD: DSM-III-R structured diagnostic interviews and blind raters were used to conduct a 4-year follow-up of siblings from ADHD and control families. The siblings were also evaluated for cognitive, achievement, social, school, and family functioning. RESULTS: At follow-up, significant elevations of behavioral, mood, and anxiety disorders were found among the siblings of ADHD children. The high-risk siblings had high rates of school failure and showed evidence of neuropsychological and psychosocial dysfunction. These impairments aggregated among the siblings who had ADHD. CONCLUSIONS: The siblings of ADHD children are at high risk for clinically meaningful levels of psychopathology and functional impairment. In addition to supporting hypotheses about the familial transmission of ADHD, the results suggest that the high-risk siblings might be appropriate targets for primary preventive interventions.     

Familial subtypes of attention deficit hyperactivity disorder: a 4-year follow-up study of children from antisocial-ADHD families

ADHD is a familial disorder with high rates of comorbidity with conduct disorder in childhood and antisocial personality and substance use disorders in adulthood. A growing literature suggests that ADHD with antisocial comorbidity may be nosologically distinct from other forms of ADHD. Previously, we proposed a family-based stratification that defined Antisocial families as those with either conduct disorder or antisocial personality disorder in the probands or relatives. To provide predictive validity for that stratification, we assessed psychopathology in these families 4 years after their initial assessment. Results show that the probands and siblings from Antisocial families had higher rates of psychopathology during the 4-year follow-up period compared with siblings from Non-antisocial and control families. They also had more deviant ratings on the Child Behavior Checklist (especially for anxious/depressed, delinquent, and aggressive behavior). We found fewer group differences in the academic, psychosocial, and intellectual correlates of ADHD. These results confirm and extend previous work indicating that Antisocial ADHD may be a nosologically and clinically meaningful subform of ADHD.     

Identifying a distinctive familial frequency band in reaction time fluctuations in ADHD.

Objective: Patients with ADHD are typically more variable in their reaction times (RT) than control children. Signal processing analyses have shown that time series RT data of children with ADHD have a distinctive low frequency periodic structure suggestive of a pattern of occasional spontaneous performance lapses. Here we use a fine-grained analysis of spectral power across a broader frequency range to differentiate the periodic qualities of ADHD time series RT data from (a) 1/frequency noise, and (b) control performance. We also assess the familiality of these frequencies by using a proband-sibling design. Method: Seventy-one children with ADHD, one of their siblings, and 50 control participants completed a simple RT task. Power across the RT frequency spectrum was calculated. The frequencies significantly differentiating the two groups were identified. Familiality was assessed in two ways: first, by comparing probands with their unaffected siblings and controls, and, second, by investigating the siblings of neuropsychologically impaired and unimpaired children with ADHD. Results: Analyses converged to highlight the potential importance of the .20–.26 Hz band in differentiating the periodic structure of ADHD RT time series data from both 1/frequency noise and control performance. This frequency band also showed the strongest evidence of familiality. Conclusions: RT performance of children with ADHD had a distinctive periodic structure. The band identified as most differentiating and familial was at a higher frequency than in most previous reports. This highlights the importance of employing tasks with faster interstimulus intervals that will allow a larger portion of the frequency spectrum to be examined. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Families of children with attention deficit hyperactivity disorder: a review

OBJECTIVES: 1) To review the evidence of attention deficit hyperactivity disorder (ADHD) and other conditions in family members (siblings and parents) of children with ADHD and determine the importance of genetic and environmental factors in this condition. 2) To describe the prospective 10-year follow-up of 65 families with ADHD children and 43 families of matched normal controls. 3) To review various studies that have looked at parent-child interactions with ADHD children on and off stimulant medication, and such interactions over time. The paper thus provides an overview of family pathology and functioning of families of ADHD children over time. METHOD: The paper outlines twin, sibling, family and adoption studies with regard to possible genetic and environmental factors in ADHD. It also presents data of a prospective 10-year follow-up of 65 families with ADHD children and 43 families of normal controls. This family study evaluated sociocultural factors, child rearing practices, health of family members and relationships, as well as the parental view of the child's functioning over time. RESULTS: A review of the literature suggests that ADHD has a strong genetic component, but that environmental factors also play an important role. Families of children with ADHD have more problems than families of normal controls, but these problems improve as the child with ADHD grows up and leaves home. Families of ADHD subjects can appreciate positive as well as negative changes in their children over time. Generally, family interactions with children with ADHD are problematic but improve when the child is on medication and when the child becomes an adult. CONCLUSIONS: This condition has strong genetic underpinnings; therefore, diagnosing and treating family members (parents and siblings) as well as the child with ADHD is important in improving parent-child interactions and better long-term outcome for the child and his or her family.     

Family-genetic study of executive functioning in attention-deficit/hyperactivity disorder: Evidence for an endophenotype?

This study examined familiality of attentional control and mental flexibility in multiplex attention-deficit/hyperactivity disorder (ADHD) families. The authors hypothesized that siblings of ADHD probands, although not behaviorally expressing ADHD, have deficits in these executive functions and that the performance of probands, unaffected siblings, and control participants are on a continuum. Participants (aged 6 to 17) were 25 ADHD probands with a family history of ADHD, their 25 unaffected siblings, and 48 control participants. The unaffected siblings did not differ from the ADHD probands on attentional control or on some measures of mental flexibility. Linear changes in performance across the groups reflected an intermediate position of the unaffected siblings between the probands and control participants. These results suggest that these executive functions may be suitable endophenotypes of ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diagnostic accuracy of the Child Behavior Checklist scales for attention-deficit hyperactivity disorder: A receiver-operating characteristic analysis.

The diagnostic accuracy of the Child Behavior Checklist (CBCL) scales for attention deficit hyperactivity disorder (ADHD) were examined using receiver-operating characteristic (ROC) analysis. Three logistic regression models were estimated in an initial sample of 121 children (aged 6–18 yrs) with and without ADHD. These models were then tested in a cross-validation sample (N?=?122) and among the 111 brothers and 108 sisters of the initial and cross-validation samples. In all 4 groups, the CBCL Attention Problems scale had the highest discriminating power for ADHD. Adding other scales did not increase the area under the curve of the ROC significantly. Findings suggest that the CBCL Attention Problems scale could serve as a rapid and useful screening instrument not only to help identify cases likely to meet criteria for ADHD in clinical settings, but also to identify cases of ADHD among the siblings of children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of reward and response costs on inhibition in ADHD children.

This study examined effects of reward and response costs on the ability of 19 attention-deficit hyperactivity disorder (ADHD) and 17 control children to inhibit responding. Children were tested under 4 reinforcement conditions on a go/no-go learning task developed by J. P. Newman, C. S. Widom, and S. Nathan (1985). Two conditions involved both reward and response costs, 1 response costs only, and 1 reward only. ADHD children made more commission errors than controls across the 4 conditions. Analyses of learning curves indicated that group differences became larger on later trials. Thus, impaired inhibition was more generalized in ADHD children than in the psychopaths and extraverts studied by Newman and colleagues, and it became most evident when the children were required to improve learning across trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of ADHD boys: A 12-year follow-up.

12 yrs after initial assessment, 33 male attention deficit hyperactivity disorder (ADHD) Ss (aged 14.4–24.9 yrs) were compared with 52 normal controls. Controls (selected at follow-up) were sex-, SES-, language-, and age-matched. According to childhood scores from the IOWA Conners Teacher Rating Scale, 24 ADHD Ss were inattentive/overactive (IO) and 9 were aggressive plus inattentive/overactive (A–IO). Ss and parents were interviewed and Ss completed a battery of tests. Core deficits of the disorder persisted in more than half of the ADHD group. IO Ss did not differ significantly from the controls in psychiatric functioning, except for their persistent ADHD. A–IO Ss had received the most individual and residential treatment for their behavior problems. ADHD Ss experienced significantly more problems in high school and displayed significantly poorer spelling, arithmetic, and reading comprehension skills than did controls. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What Aspects of Peer Relationships Are Impaired in Children With Attention-Deficit/Hyperactivity Disorder?

Participants included 165 children with attention-deficit/hyperactivity disorder (ADHD; 130 boys, 35 girls) and their 1,298 same-sex classmates (1,026 boys, 272 girls) who served as raters. For each child with ADHD, a child of the same sex was randomly selected from the same classroom to serve as a comparison child, which yielded 165 dyads. Consistent with predictions, contrasted with the comparison children, those with ADHD were lower on social preference, higher on social impact, less well liked, and more often in the rejected social status category; they also had fewer dyadic friends. When liking ratings that children made versus received were examined, children with ADHD had less positive imbalance and greater negative imbalance relative to comparison children. Analyses that considered the types of peers who chose children with ADHD as friends or nonfriends demonstrated that children with ADHD were nominated as nonfriends by children of higher social preference and who were better liked by others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)