Attention Deficit Hyperactivity Disorder Subgroups Research Articles

Somatosensory function in boys with ADHD and tactile defensiveness

In this study, we tested for deficits in somatosensory function in boys with Attention Deficit Hyperactivity Disorder (ADHD) and tactile defensiveness (TD). The subjects were 67 boys with ADHD, sub-typed as TD (ADHD+TD+) or non TD (ADHD+TD−), matched with 60 “typical” children in the control group. Sixty nine percent of the boys with ADHD were categorized as TD. The groups were compared on three measures: (a) performance scores on subtests of the Sensory Integration and Praxis Test, (b) measurements of the Somatosensory Evoked Potential (SEP) and (c) ratings of the children's affective responses during tactile stimulation. Both ADHD groups differed from the control group on most study measures. No significant differences were found between the two ADHD subgroups on threshold and perceptual tests scores, except for Finger Identification. However, the TD+ group demonstrated significantly higher central SEP amplitudes than did the TD− group. Together, the results support claims that TD is related to central processing of somatosensory information, but not to anomalous tactile perception, with the exception of Finger Identification.

Dissecting the attention deficit hyperactivity disorder (ADHD) phenotype: Sustained attention, response variability and spatial attentional asymmetries in relation to dopamine transporter (DAT1) genotype

ADHD is a childhood-onset behavioural disorder with a heterogeneous profile of neuropsychological impairment. Neuropsychological heterogeneity may, in part, reflect underlying genetic differences. Here we examined sustained attention, response variability and spatial attentional asymmetries in a sample of children and adolescents with ADHD ( n = 22) in relation to dopamine transporter genotype (DAT1) and also controls ( n = 20). Participants performed the sustained attention to response task (SART) (testing sustained attention and response variability) and the greyscales task (a perceptual measure of attentional bias). The latter has previously been shown to yield a robust leftward attentional asymmetry in healthy subjects. The 10-repeat allele of the DAT1 gene has been associated with ADHD in a number of studies and appears to have biological significance. The ADHD group was sub-divided into those individuals with two copies of the “high-risk” 10-repeat allele (high-risk DAT1) versus those with one or no copies of this allele (low-risk DAT1). The high-risk DAT1 ADHD group displayed greater response variability on the SART than either the low-risk DAT1 group or healthy controls, whereas the latter two groups did not differ. Further, the high-risk DAT1 group showed an attenuated spatial asymmetry, relative to the low-risk DAT1 ADHD group, who showed the typical leftward attentional asymmetry. Our results suggest that the 10-repeat DAT1 allele may mediate neuropsychological impairment in ADHD. The application of molecular genetics may help to define neuropsychological impaired subgroups of ADHD.

Síndrome de déficit de atención con hiperactividad y capacidad para el deporte

To know the sportive activities of children and adolescents, males, with attention deficit-hyperactivity disorder (ADHD).There were studied 100 patients, all males, with ages ranging 6 to 16 years (average: 9.28 years), 50 of the hospital and 50 of the private consultation. The subgroup of ADHD was identified in all patients. The patients were asked on the sports most usually made, although the response had to be confirmed by the parents.Twenty-five cases showed attention deficit, 16 hyperactivity, and 59 combined form. If only one sport is to have had in consideration, football was the most practiced sport, with 20 cases. If a second sportive activity was also considered, cycling was the most practiced sport, with 29 cases, while only 23 patients played football (more than a 50% as goalkeeper) if we wanted the two first options. A less number of cases made basketball, swimming, judo or taekwondo, vasque ball and several others. Thirty three patients did not make any sport and most of them showed an unsporting attitude. Less than a half of the cases showed motivation to practice sport and less than a third was disciplined obeying the orders of the coach and/or the leader.The patients with ADHD mostly show little motivation for the sport activities, being cycling and football (preferable as goalkeeper) the two most frequently practiced. The patients usually show little motivation and discipline.

Attention deficit hyperactivity disorder in adults—early vs. late onset in a retrospective study

Attention deficit hyperactivity disorder (ADHD) is a severe and often debilitating mental disorder, which begins in childhood and can persist into adulthood. Both major classificatory systems, ICD-10 and DSM-IV, include the age-of-onset criterion (AOC) requiring clinically relevant symptoms before the age of 7 years. In clinical practice, particularly in adult psychiatry, it is often difficult to establish this AOC when ADHD remained unrecognized in childhood. In the literature, there is controversy about the validity of this criterion. In order to explore the validity of the AOC, we performed a retrospective study in adult patients with ADHD. Fifty consecutively diagnosed patients were subjected to a standardized diagnostic procedure. Depending on the onset of clinical symptoms, patients were divided in an early onset and in a late onset ADHD subgroup. Fourteen patients (28%) described late onset ADHD. In four of these patients (8% of the total sample), this assessment was confirmed by parent ratings. There was no difference between early onset and late onset ADHD groups in terms of psychopathology or psychiatric comorbidity.

Attention deficit hyperactivity disorder with bipolar disorder in girls: further evidence for a familial subtype?

Background: To clarify the nosologic status of girls with attention deficit hyperactivity disorder (ADHD) who also satisfy diagnostic criteria for bipolar disorder (BPD). Methods: Using blind raters and structured psychiatric interviews, we examined 140 girls with ADHD, 122 non-ADHD comparisons and their 786 first degree relatives. Analyses tested specific hypotheses about the familial relationship between ADHD and bipolar disorder in girls. Results: After stratifying our ADHD sample into those with and without BPD, we found that: (1) relatives of both ADHD subgroups were at significantly greater risk for ADHD than relatives of non-ADHD controls, (2) the two subgroups did not significantly differ in their relatives’ risk for ADHD; (3) an elevated risk for bipolar disorder was observed among relatives when the proband child had BPD but not ADHD alone; (4) weak evidence of cosegregation between ADHD and BPD, and (5) no evidence of a trend for random mating between ADHD parents and those with mania. Limitations: Limitations of this study include the lack of direct interviewing of probands and the limited number of ADHD/BPD probands available. Conclusions: These findings extend to girls what was previously documented in boys and suggest that comorbid ADHD with BPD in girls is familially distinct from other forms of ADHD and may be related to what others have termed childhood onset BPD. Future work could determine if this subgroup has a characteristic course, outcome and response to treatment.

Attention deficit/hyperactivity disorder children with a 7-repeat allele of the dopamine receptor D4 gene have extreme behavior but normal performance on critical neuropsychological tests of attention.

An association of the dopamine receptor D4 (DRD4) gene located on chromosome 11p15.5 and attention deficit/hyperactivity disorder (ADHD) has been demonstrated and replicated by multiple investigators. A specific allele [the 7-repeat of a 48-bp variable number of tandem repeats (VNTR) in exon 3] has been proposed as an etiological factor in attentional deficits manifested in some children diagnosed with this disorder. In the current study, we evaluated ADHD subgroups defined by the presence or absence of the 7-repeat allele of the DRD4 gene, using neuropsychological tests with reaction time measures designed to probe attentional networks with neuroanatomical foci in D4-rich brain regions. Despite the same severity of symptoms on parent and teacher ratings for the ADHD subgroups, the average reaction times of the 7-present subgroup showed normal speed and variability of response whereas the average reaction times of the 7-absent subgroup showed the expected abnormalities (slow and variable responses). This was opposite the primary prediction of the study. The 7-present subgroup seemed to be free of some of the neuropsychological abnormalities thought to characterize ADHD.

Social Functioning and Emotional Regulation in the Attention Deficit Hyperactivity Disorder Subtypes

Compared 16 children with attention deficit hyperactivity disorder (ADHD) combined type (ADHD-C), 14 children with ADHD predominantly inattentive type (ADHD-I), and 17 controls on parent and teacher ratings of social status and performance, self-report of social knowledge and performance, and observations of behavior on an emotional regulation task. Analyses revealed distinct patterns of social dysfunction between ADHD subgroups. Children with ADHD-C were rated as showing more aggressive behavior; furthermore, they displayed emotional dysregulation characterized by high intensity and high levels of both positive and negative behavior. In contrast, children with ADHD-I were perceived as displaying social passivity and showed deficits in social knowledge on the self-report measure but did not evidence problems in emotional regulation. Regression analyses revealed that social performance, emotional regulation, and, to a lesser degree, social knowledge, were predictive of social status. The application of these findings to understanding the nature of the social deficits in the ADHD subtypes and directions for future research are discussed.

Behavioral and executive functions in children with Attention-Deficit Hyperactivity disorder and reading disability

Attention, impulse control, activity level, and motor decision/response organization were assessed in 70 child psychiatric outpatients, using a continuous performance test (CPT), a solid-state actigraph, and a response incompatibility task. Subjects were divided based on the presence or absence of attention-deficit hyperactivity disorder (ADHD) and/or reading disability (RD). Two-way ANOVAs yielded significant main effects for ADHD, but not RD, on objective measures of impulsivity and overactivity. No significant differences were found on a CPT measure of inattention. The response incompatibility task revealed differential performance between ADHD subgroups with and without comorbid RD. Deficits in motor decision/response organization were observed in the ADHD-only subgroup, but not in the comorbid ADHD+RD subgroup. These findings suggest that children with ADHD, RD and comorbid ADHD+RD have at least partially distinct underlying cognitive and neuropsychological disturbances, and that executive function deficits may be present primarily in ADHD children without RD.

Deficient inhibitory control in attention deficit hyperactivity disorder.

The purpose of this study was to examine two executive control processes--response inhibition and re-engagement of responses after inhibition in children with attention deficit hyperactivity disorder (ADHD). Thirty-three children with ADHD and 22 normal control children of similar age (7 to 11 years) and mean IQ (107) were tested with the change paradigm. ADHD subgroups were defined by the context in which the ADHD symptoms predominated (in the home only; at school only; and in both, i.e., pervasive ADHD). Children with marked oppositional defiant or conduct disorder were excluded. Children with ADHD exhibited deficits in inhibitory control and in response re-engagement. Deficits were greatest in pervasive ADHD and, to a lesser extent, in those with ADHD limited to the school context. ADHD limited to the home context showed the least deficit. These results replicate an earlier study that found deficient inhibitory control in pervasive ADHD and demonstrate that the deficit in ADHD involves a second aspect of executive control.

Is Decreased Blood Plasma Concentration of the Complement C4B Protein Associated with Attention-Deficit Hyperactivity Disorder?

The complement system is a group of blood proteins that play an important role in defending against viral and bacterial infections. The objective of this investigation was to study the plasma levels of the C4B protein in attention-deficit hyperactivity disorder (ADHD) in an attempt to associate infections with the development of some cases of this disorder. C4B plasma protein levels were studied using an enzyme-linked immunosorbent assay in a group of 23 subjects meeting DSM-III-R criteria for ADHD and a similar number of age- and sex-matched controls. Also studied were parents of the ADHD subjects. C4B plasma levels (157.0 micrograms/mL) in the ADHD subjects were significantly (p < .01) lower than those (239.3 micrograms/mL) in the normal age-matched subjects. Mothers of the ADHD subjects also had significantly lower C4B values compared with mothers of normal children. On the other hand, C4B values in the fathers were not significantly altered. Decreased C4B levels in ADHD, if replicated, may represent an important marker for ADHD (or a subgroup of ADHD). It also seems plausible that C4B levels are an important etiological factor for ADHD.

Multimethod assessment of covert antisocial behavior in children: Laboratory observations, adult ratings, and child self-report.

Given the high risk for delinquency of children with attention-deficit hyperactivity disorder (ADHD), their display of covert or clandestine antisocial behavior is important developmentally and theoretically. In a laboratory probe of the temptation to (a) steal small amounts of money and desired objects, (b) destroy property, and (c) use an answer key to cheat on a worksheet, counts of these covert behaviors were reliably made. Laboratory property destruction was highly correlated with parallel naturalistic behaviors. Stealing and property destruction (but not cheating) formed a factor that was distinct from overt physical and verbal aggression. These covert indexes clearly distinguished ADHD from comparison samples as well as high- from low-aggressive ADHD subgroups ; they showed external validity with maternal reports, global staff ratings, and child self-reports of similar constructs. The authors discuss psychometric and ethical issues in the assessment of covert antisocial behavior.

Effects of Methylphenidate on Processing Negativities in Patients With Attention‐deficit Hyperactivity Disorder

This study compared the impact of methylphenidate on patients with Attention-deficit Hyperactivity Disorder (ADHD) with and without aggressive/noncompliant features in an oddball test consisting of a randomly ordered series of loud (frequent) tones, soft (rare) tones, bright (frequent) lights, and dim (rare) lights. In alternate conditions, subjects were required to respond to either the rare tones or the rare lights. These tasks were administered in a drug-free baseline session and after a counterbalanced treatment of 14 days each of methylphenidate (0.3 mg/Kg b.i.d.) and placebo (lactose b.i.d.). In comparison with placebo, methylphenidate resulted in greater accuracy and speed of reactions to targets of both modalities. The amplitude of N1 to auditory nontargets was larger when the target was a rare tone as opposed to a rare light, and this attention-related effect was increased by methylphenidate. The same differential amplitude enhancement by stimulant treatment was found for an early area measure of difference ERPs. In contrast, for N1 to visual nontargets the effect of selective attention (larger amplitude when the target was a rare light vs. a rare tone) was not significant and was not affected by stimulant medication. All these findings were comparable for the three ADHD subgroups, a result attesting to the generality of stimulant effects on information processing.