A person-centered personality approach to heterogeneity in attention-deficit/hyperactivity disorder (ADHD).

Person-centered personality approaches are an underused means of illuminating clinical heterogeneity of attention-deficit/hyperactivity disorder (ADHD). In the present study, latent profile analysis was conducted with personality traits to identify homogeneous profiles within the ADHD population. Participants were 548 children ages 6–18 years (302 with ADHD). Personality traits were measured via parent report on the California Q-Sort (A. Caspi et al., 1992). Latent profile analysis was conducted on the Big 5 factors. A 6-profile solution best fit the data. Resulting groups were characterized as “disagreeable,” “introverted,” “poor control,” “well adjusted,” “extraverted,” and “perfectionistic.” External validation of this model using ADHD diagnosis, subtypes, and comorbid psychopathology suggested that children with ADHD could be parsed into 4 groups: (a) an introverted group with high rates of the ADHD-inattentive type, (b) a group characterized by poor control, with high rates of ADHD-combined type (ADHD-C) and comorbid disruptive behavior disorders, (c) an extraverted group, with ADHD-C and few associated comorbid disorders, and (c) possibly, a very rare “perfectionistic” group, exhibiting obsessive traits. A person-centered personality approach may be one promising way to capture homogeneous subgroups within the ADHD population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Periodic limb movement disorder and restless legs syndrome in children with attention-deficit hyperactivity disorder

Sleep disruption can lead to symptoms of attention-deficit hyperactivity disorder (ADHD) in children. Since periodic limb movement disorder and/or restless legs syndrome can cause sleep disruption, we assessed whether these two specific sleep disorders are likely to occur in children with ADHD. We asked a series of 69 consecutive parents of children with ADHD questions about the symptoms of periodic limb movement disorder. Based on a positive response to these periodic limb movement disorder queries, 27 children underwent all-night polysomnography. Eighteen children (aged 2 to 15 years) of the 27 (26% of the 69 children with ADHD) had 5 or more periodic leg movements in sleep per hour of sleep and had complaints of sleep disruption, thus fulfilling the criteria for periodic limb movement disorder. A comparably age- and sex-matched group of children referred to a sleep laboratory for sleep complaints but without ADHD showed only a 5% prevalence (2 of 38 subjects) of periodic leg movements in sleep (P=.017). Eight of the 18 children with ADHD and periodic limb movement disorder and one of the two control patients with periodic limb movement disorder had both a personal and parental history of restless legs syndrome symptomatology. This study further documents the occurrence of periodic limb movement disorder and restless legs syndrome in children and is the first large-scale study establishing a possible comorbidity between ADHD and periodic limb movement disorder. We propose that the sleep disruption associated with periodic limb movement disorder and restless legs syndrome and the motor restlessness of restless legs syndrome while awake could contribute to the inattention and hyperactivity seen in a subgroup of ADHD-diagnosed children.     

Autonomic correlates of attention-deficit/hyperactivity disorder and oppositional defiant disorder in preschool children.

Numerous studies have revealed autonomic underarousal in conduct-disordered adolescents and antisocial adults. It is unknown, however, whether similar autonomic markers are present in at-risk preschoolers. In this study, the authors compared autonomic profiles of 4- to 6-year-old children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD; n = 18) with those of age-matched controls (n = 20). Children with ADHD and ODD exhibited fewer electrodermal responses and lengthened cardiac preejection periods at baseline and during reward. Although group differences were not found in baseline respiratory sinus arrhythmia, heart rate changes among ADHD and ODD participants were mediated exclusively by parasympathetic withdrawal, with no independent sympathetic contribution. Heart rate changes among controls were mediated by both autonomic branches. These results suggest that at-risk preschoolers are autonomically similar to older externalizing children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic relationship between dopamine transporter gene and schizophrenia: linkage and association

This experiment was aimed at comparing the sensorimotor correlates of fimbria-fornix lesions made with either a classical aspiration technique that also removes part of the overlying cortical structures, or an electrolytic one that does not encroach upon these cortical structures. About 4 months after lesion surgery, Long-Evans female rats which had sustained an aspiration or an electrolytic fimbria-fornix lesion at the age of 90 days were tested to measure their beam-walking performance as an index for their sensorimotor capabilities. We found that after an aspiration lesion, the rats presented sensorimotor deficits which did not occur after an electrolytic lesion. After having found that electrolytic lesions of the fimbria and the fornix produced neurochemical deficits (in the dorsal hippocampus) and cognitive alterations close to those resulting from aspiration lesions, it is concluded from the present experiment that the electrolytic lesion technique is an interesting alternative to an aspiration technique, essentially because the former does not induce the sensorimotor deficits due to the partial damage that an aspiration technique produces in the medial parietal cortex. As the electrolytic lesion technique may minimize the risk of introducing a sensorimotor bias in the accuracy of cognitive evaluations, the present result might be of interest to neuroscientist using a fimbria-fornix lesion paradigm in order to investigate the efficacy of drugs, grafts or other treatments on the recovery from cognitive deficits.     

Magnetic resonance imaging correlates of attention-deficit/hyperactivity disorder in children.

This study compared magnetic resonance imaging size differences in several brain regions and neurocognitive function in a group of male and female children with attention-deficit/hyperactivity disorder (ADHD) with no comorbid learning disorders with a normal control group of children. The ADHD group demonstrated smaller total brain, superior prefrontal, and right superior prefrontal volumes, as well as significantly smaller areas for cerebellar lobules I-V and VIII-X, total corpus callosum area, and splenium. No group differences were observed for the inferior prefrontal, caudate, or cerebellar volumes, or for the area of cerebellar lobules VI-VII. In the ADHD group but not in the control group, greater right superior prefrontal volume predicted poorer performance on a test of sustained attention. Patterns of brain abnormality did not differ in male and female children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frontal systems dysfunction in children with attention-deficit/hyperactivity disorder and learning disabilities

OBJECTIVES: Our aim was to study the relationships between clinical efficacy of azathioprine, 6-mercaptopurine pharmacokinetics and changes in peripheral blood lymphocyte subpopulations induced by azathioprine treatment in Crohn's disease. METHODS: Twenty-three patients were prospectively followed up for 1 year. Peripheral blood counts, total lymphocytes, CD3+, CD4+, CD8+, CD25+, CD16+CD56+, CD57+ and CD19+ lymphocyte subpopulations were carried out, using flow cytometry, during azathioprine treatment. Pharmacokinetic studies were performed at day 8 and month 3 by measuring 6-mercaptopurine plasma concentration after an oral dose of azathioprine (2 mg/kg). Results were compared in responders (no activity and no steroids) and non-responders. RESULTS: The decrease in peripheral blood leukocytes and neutrophils was significant after 1 month, reaching 49% and 48% of the pre-treatment values at 1 year; the one of lymphocytes was significant after 6 months and reached 41% at 1 year. Percentages of CD3+, CD4+, CD8+, CD57+, CD16+CD56+ and CD19+ lymphocytes remained unchanged whereas percentage of CD25+ lymphocytes increased from 10% to 28% (P < 0.01). There was a high inter and intraindividual variability of 6-mercaptopurine peak plasma concentration and area under the curve. No significant difference was found between responders (n = 14) and non responders (n = 7) for pharmacokinetic parameters and lymphocyte subpopulations; there was no correlation between lymphocyte subpopulation changes and 6-mercaptopurine pharmacokinetics. CONCLUSION: Monitoring of 6-mercaptopurine plasma concentration and blood lymphocyte subpopulations is of little value in Crohn's disease patients treated with azathioprine.     

An update on the diagnosis and treatment of attention-deficit/hyperactivity disorder in children.

What are the most appropriate empirically supported diagnostic and treatment approaches to children with attention-deficit/hyperactivity disorder (ADHD)? This article summarizes the nomenclature, prevalence and course, comorbidity, etiology, assessment, and federal laws associated with ADHD. The authors then review clinical research and consensus guidelines for the treatment of ADHD, including the largest randomized treatment study completed on ADHD (MTA Cooperative Group, 1999a). The empirical evidence supports either a behavioral-psychosocial or a combined behavioral-psychosocial and medication intervention in the treatment of children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical and treatment characteristics of children with attention-deficit/hyperactivity disorder in psychiatric practice

OBJECTIVE: To capture information about the clinical characteristics of, and treatments for, children with attention-deficit/hyperactivity disorder (ADHD) in psychiatric practice. METHOD: A mailed, self-administered questionnaire was sent to 81 practicing psychiatrists for them to complete on the next three consecutive patients aged 14 years and younger with ADHD seen during the 12-day study period. Information collected included the sociodemographic, clinical, and treatment characteristics of sampled patients. RESULTS: Patients in the study were predominantly white (85%), male (78%), and between 10 and 14 years old (58%). The most common ADHD subtype was combined/predominantly hyperactive (86%); 31% had no other comorbidity. Ninety-seven percent were receiving medications, with 49% receiving two or more. The single most common medication reported was methylphenidate (51% of patients) followed by clonidine (20%). Psychotropics other than psychostimulants were used in a majority of patients (55%). CONCLUSIONS: Psychiatrists, and child and adolescent psychiatrists in particular, see a more severely impaired and complex group of patients than would be expected of primary care providers. The treatment patterns of psychiatrists for these patients do not reflect the simpler treatments usually studied in clinical trials.     

Effect of methylphenidate on motivation in children with attention-deficit/hyperactivity disorder.

The effects of methylphenidate (MPH) on motivation were examined using a progressive ratio (PR) task in children who were prescribed MPH for the treatment of ADHD. Twenty-one children, 7 to 12 years of age, completed two test sessions, one under the effects of medication and one not. During each session, children pressed a lever to earn nickel reinforcers, where the first press resulted in a reinforcer and 10 additional presses were required for each subsequent reinforcer. Children on MPH had a significantly higher breakpoint than when off medication. This MPH-associated increase in the breakpoint manifested as a significant decrease in the interresponse times (IRT). Further, MPH administration resulted in a significant decrease in IRT variability. In contrast, MPH administration had no significant effects on the means and variability of postreinforcement pause duration. These results suggest that MPH increased motivation in children being treated for ADHD. Further, the inability of MPH to significantly reduce postreinforcement pause duration while simultaneously decreasing IRTs suggests that while MPH may increase motivation to perform an ongoing task, it may have little effect on the initiation of that task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Inspection time and attention-deficit/hyperactivity disorder symptoms in children with cerebral palsy.

Objective: To examine between-groups differences in the associations between aspects of processing speed assessed with an inspection time task and attention-deficit/hyperactivity disorder (ADHD) symptoms. Research Design: Two groups comprising 34 children with cerebral palsy (CP) and 70 nonaffected peers (control), ages 8–16 years, participated in a prospective correlational study. Measures included a visual inspection time task and the Conners' Parent Rating Scale—Revised: Long Version. Results: Children with CP exhibited significantly slower processing speed and more symptoms of inattention and hyperactivity than controls. Significant associations between inspection time and ADHD symptoms were found only in the control group. Conclusions: Findings have implications for clinical assessment and understanding of attentional risks associated with CP. (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)     

Use of the Differential Ability Scales for children with attention-deficit/hyperactivity disorder.

The validity of the Differential Ability Scales (DAS) was assessed among children with attention-deficit/hyperactivity disorder (ADHD) and a matched control sample. The sample included 45 children with ADHD (69% with comorbidity) and 45 controls matched by age, gender, ethnicity, and parental educational level. Multivariate analysis of variance univariate test results and d ratios yielded statistically and clinically significant group differences on the Recall of Digits and Recall of Objects-Immediate diagnostic subtests. Discriminant function analyses indicated that the three Diagnostic Subtests accurately classified 67% of the sample with 69% correctly identified as controls and 64% correctly identified as ADHD. Recall of Digits was found to make the most significant contribution overall to the discriminant function. At a cutoff score of 40, Recall of Digits yielded high specificity and low sensitivity and moderate positive predictive power. Implications of results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task engagement and mathematics performance in children with attention-deficit hyperactivity disorder: Effects of supplemental computer instruction.

Examined the effects of using software with a game format (as a supplement to teacher instruction) to improve math performance of 3 male 4th- to 6th-grade students with attention-deficit hyperactivity disorder. Following baseline (observation under normal classroom conditions), the math software was introduced sequentially using a multiple baseline design across participants. Observational data were collected during the baseline and experimental conditions along with a set of curriculum-based math probes, which were used throughout the study. The hypothesis that math software with a game format would improve the academic performance and increase attention of all participants was partially supported. Implications for practice and further research are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Cocaine abuse and attention-deficit hyperactivity disorder: Implications of adult symptomatology.

Forty-three men between the ages of 18 and 48, in treatment for cocaine abuse or dependence, were evaluated for history of childhood attention-deficit hyperactivity disorder (ADHD) and adult symptoms (residual state). Participants completed a quantitative cocaine history and an interview designed to explore subjective cocaine experience. High ADHD scores were significantly correlated with high gram use of cocaine, r(41)?=?.37, p?r(41)?=?–.62, p?r(41)?=?.42, p?r(41)?=?.31, p?r(41)?=?.32, p?     

Brain morphometry in Tourette's syndrome: the influence of comorbid attention-deficit/hyperactivity disorder

Three separate groups, using MRI, have reported basal ganglia abnormalities in Tourette's syndrome (TS). We found similar abnormalities in boys with attention-deficit/hyperactivity disorder (ADHD). Because TS and ADHD are frequently comorbid, we contrasted ADHD boys with and without TS along with control subjects. As expected, we found a significant loss of the normal globus pallidus asymmetry in the patients, but presence or absence of TS did not differentiate the ADHD groups. We conclude that accounting for ADHD comorbidity will be important in future TS morphometric studies.     

Titrating methylphenidate in children with attention-deficit/hyperactivity disorder: is body mass predictive of clinical response?

We report here on strategies aimed at improving the frequency of detectable recombination in plants by increasing the efficiency of selecting double-recombinants in transgenic calli. Gene targeting was approached on the Gln1 and the Pzfloci of Lotus japonicus, using Agrobacterium tumefaciens T-DNA replacement vectors. Large flanking regions, up to 22.9 kb, surrounding a positive selection marker were presented as substrates for homologous recombination. For easier detection of putative recombinants the negative selectable marker cytosine deaminase was inserted at the outside borders of the flanking regions offered for cross-over. A combination of positive and negative selection allowing double-recombinants to grow, while counter-selecting random insertions, was used to select putative targeting events. The more than 1000-fold enrichment observed with replacement vectors designed to minimize gene silencing demonstrated the efficiency of the negative selection. Using five different replacement vectors an estimated total of 18,974 transformation events were taken through the positive-negative selection procedure and 185 resistant calli obtained. Targeting events could not be verified in the survivors by PCR screening and Southern blot analysis. With this approach the frequency of detectable gene targeting in L. japonicus was below 5.3 x 10(-5), despite the large flanking sequences offered for recombination.     

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: Parametric measurement of attention.

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a “theory of visual attention.” These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Gender study of neuropsychological and neuromotor function in children with Tourette syndrome with and without attention-deficit hyperactivity disorder

Neuropsychological and neuromotor functions were compared between boys and girls with Tourette syndrome (TS only), attention-deficit hyperactivity disorder (ADHD only), Tourette syndrome with ADHD (TS+ADHD), and a comparison group, in an age (mean = 10 years) and IQ (Wechsler Full-Scale mean = 111) matched sample (n = 116). There were no timed-task neuromotor differences among the groups. Analyses of variance revealed a group x gender interaction for Letter Word Fluency and the Rapid Automatized Naming test. Girls with ADHD only were faster than boys on both tasks. When data for girls only were analyzed, girls with Tourette syndrome with ADHD had the greatest variability of reaction time on the Test of Variables of Attention, and were slowest on Letter Word Fluency. Girls with TS only were slower than girls in the other three groups on Letter Word Fluency. Poor Letter Word Fluency is explained as a linguistic executive dysfunction involving speed and efficiency of memory search in this bright group of girls with Tourette syndrome, not otherwise at risk for linguistic difficulties.     

Differences in plasma concentrations of the D- and L-threo methylphenidate enantiomers in responding and non-responding children with attention-deficit hyperactivity disorder

In Wistar rats, the ED-50 of kainic acid induced clonic seizures. In early and postponed periods of kindling, the ED-50 decreased by 2,0 to 1.5 times. Kyotorphin did not affect the ED-50 of kainic acid in postponed periods.     

Token reinforcement and response cost procedures: Reducing the disruptive behavior of preschool children with attention-deficit/hyperactivity disorder.

Compared the effects of a token reinforcement and a response cost intervention in reducing the disruptive behavior of 4 preschool children (aged 4.3–5 yrs old) with attention deficit hyperactivity disorder (ADHD). The results of a single-subject withdrawal design counterbalanced between Ss showed that both interventions were effective in reducing disruptive student behavior. Both interventions were rated as highly acceptable by the children's preschool teachers, although the teachers expressed a preference for response cost. Implications of the results are discussed for future research and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)