To what extent are task-switching deficits in children with attention-deficit/hyperactivity disorder independent of impaired inhibition?

Executive functions, higher-order cognitive functions needed for goal-directed behavior, have been studied extensively in the search for endophenotypes for ADHD, yet results have been inconclusive. We examine the performance of children with ADHD in task switching as an as yet understudied potential endophenotype. A group of 20 children with ADHD and a group of 23 children without ADHD (ages 7?C12) performed a task-switching paradigm and a Go/No-Go Task. Children with ADHD displayed significantly greater specific switch costs, that is, compared to control children they were especially impaired directly after task switches. There were no group differences with respect to the general switch costs, which are estimated by comparing performance on single task blocks to the block where both tasks are intermixed. Specific switch costs and Go/No-Go error rate were significantly correlated; yet, group differences in the task-switching paradigm remained significant even when inhibition was controlled for. This pattern of results suggests that children with ADHD are neither generally impaired in executive function nor only impaired with respect to inhibition. Instead, they display a highly specific deficit with regard to the flexible suppression and amplification of different task rules according to the context. Our conclusion that task switching has the potential to be added to the list of ADHD endophenotypes is strengthened by the independence of task-switching deficits and inhibition.     

Potential cognitive endophenotypes in multigenerational families: segregating ADHD from a genetic isolate

Endophenotypes are neurobiological markers cosegregating and associated with illness. These biomarkers represent a promising strategy to dissect ADHD biological causes. This study was aimed at contrasting the genetics of neuropsychological tasks for intelligence, attention, memory, visual-motor skills, and executive function in children from multigenerational and extended pedigrees that cluster ADHD in a genetic isolate. In a sample of 288 children and adolescents, 194 (67.4%) ADHD affected and 94 (32.6%) unaffected, a battery of neuropsychological tests was utilized to assess the association between genetic transmission and the ADHD phenotype. We found significant differences between affected and unaffected children in the WISC block design, PIQ and FSIQ, continuous vigilance, and visual-motor skills, and these variables exhibited a significant heritability. Given the association between these neuropsychological variables and ADHD, and also the high genetic component underlying their transmission in the studied pedigrees, we suggest that these variables be considered as potential cognitive endophenotypes suitable as quantitative trait loci (QTLs) in future studies of linkage and association.     

Cortisol responses in children and adults with attention deficit hyperactivity disorder (ADHD): a possible marker of inhibition deficits

Attention deficit hyperactivity disorder (ADHD) is a heterogeneous disease whose neurobiological background is not completely understood. It has been proposed that deficits of the inhibitory function with an underactive behavioral inhibition system (BIS) may be in the core of ADHD. In this regard, this review summarizes all studies that examine the involvement of cortisol in ADHD. Differences in cortisol responses from different ADHD subtypes, hyperactive/impulsive, inattentive, and combined, are analyzed. In addition, we examine the role of comorbidities as confounding factors in the study of cortisol in ADHD, including comorbid disruptive behavioral disorder (DBD), as well as anxiety and depressive disorders. Because ADHD is a neurodevelopmental condition and approximately half of the children enter adulthood with the disorder, we review cortisol studies in adults and children separately. Two diverse patterns of cortisol have been reported both in children and adults with ADHD. Blunted cortisol responses to stress are associated with comorbid DBD, whereas high cortisol responses are associated to comorbid anxiety disorders. Nevertheless, the inhibitory deficits in ADHD do not appear to be related directly to cortisol deficits in either children or adults. This review increases our understanding of the heterogeneity of ADHD and could help in determining new strategies for the treatment of these patients. Future studies including gender and a more systematic methodology to study the cortisol response are needed.     

Response Inhibition Impairment in High Functioning Autism and Attention Deficit Hyperactivity Disorder: Evidence from Near-Infrared Spectroscopy Data

Background

Response inhibition, an important domain of executive function (EF), involves the ability to suppress irrelevant or interfering information and impulses. Previous studies have shown impairment of response inhibition in high functioning autism (HFA) and attention deficit hyperactivity disorder (ADHD), but more recent findings have been inconsistent. To date, almost no studies have been conducted using functional imaging techniques to directly compare inhibitory control between children with HFA and those with ADHD.

Method

Nineteen children with HFA, 16 age- and intelligence quotient (IQ)-matched children with ADHD, and 16 typically developing (TD) children were imaged using functional near-infrared spectroscopy (NIRS) while performing Go/No-go and Stroop tasks.

Results

Compared with the TD group, children in both the HFA and ADHD groups took more time to respond during the No-go blocks, with reaction time longest for HFA and shortest for TD. Children in the HFA and ADHD groups also made a greater number of reaction errors in the No-go blocks than those in the TD group. During the Stroop task, there were no significant differences between these three groups in reaction time and omission errors. Both the HFA and ADHD groups showed a higher level of inactivation in the right prefrontal cortex (PFC) during the No-go blocks, relative to the TD group. However, no significant differences were found between groups in the levels of oxyhemoglobin concentration in the PFC during the Stroop task.

Conclusion

Functional brain imaging using NIRS showed reduced activation in the right PFC in children with HFA or ADHD during an inhibition task, indicating that inhibitory dysfunction is a shared feature of both HFA and ADHD.     

Protopathic stimulant use among children with symptoms of ADHD

The purpose of the current study was to examine protopathic stimulant use among children with the symptoms of ADHD but do not have a diagnosis of ADHD. Protopathic or prodromal stimulant use refers to the use of stimulants by children with the symptoms of ADHD prior to a diagnosis of ADHD. In the current study, we examined children with the symptoms of ADHD who received stimulant treatment across time and with respect to several background variables. Our results indicate that these children who receive stimulant treatment without a diagnosis of ADHD are significantly more like to be eventually diagnosed with ADHD than not. Results also indicate that these children who receive stimulant treatment but do not yet have a diagnosis of ADHD are significantly more likely to have insurance that does not pay for diagnostic procedures. These results are discussed in view of treatment.     

Methylphenidate and if-then plans are comparable in modulating the P300 and increasing response inhibition in children with ADHD

A disturbed functioning of the prefrontal cortex, the anterior cingulate cortex, and an accordingly reduced P300 presumably underlies executive function deficits of children with attention deficit hyperactivity disorder (ADHD). Using a combined classification and Go/NoGo task paradigm, the present study investigated whether medication with methylphenidate (MPH) modulates the P300 as measured by a high-density electroencephalogram (EEG) and facilitates response inhibition in children with ADHD. Further, effects of MPH were compared with effects of self-regulation by if-then plans (Gollwitzer in Am Psychol 54: 493-503, 1999). MPH as well as if-then plans modulated the P300 and improved inhibition of an unwanted response on a Go/NoGo task to the same level observed in children without ADHD. Importantly, self-regulation strategies might be a valuable alternative to medication with MPH in children with ADHD.     

The Strengths and Difficulties Questionnaire as a Predictor of Parent-Reported Diagnosis of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder

The Strengths and Difficulties Questionnaire (SDQ) is widely used as an international standardised instrument measuring child behaviour. The primary aim of our study was to examine whether behavioral symptoms measured by SDQ were elevated among children with autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) relative to the rest of the population, and to examine the predictive value of the SDQ for outcome of parent-reported clinical diagnosis of ASD/ADHD. A secondary aim was to examine the extent of overlap in symptoms between children diagnosed with these two disorders, as measured by the SDQ subscales. A cross-sectional secondary analysis of data from the Millennium Birth Cohort (n = 19,519), was conducted. Data were weighted to be representative of the UK population as a whole. ADHD or ASD identified by a medical doctor or health professional were reported by parents in 2008 and this was the case definition of diagnosis; (ADHD n = 173, ASD n = 209, excluding twins and triplets). Study children''s ages ranged from 6.3–8.2 years; (mean 7.2 years). Logistic regression was used to examine the association between the parent-reported clinical diagnosis of ASD/ADHD and teacher and parent-reported SDQ subscales. All SDQ subscales were strongly associated with both ASD and ADHD. There was substantial co-occurrence of behavioral difficulties between children diagnosed with ASD and those diagnosed with ADHD. After adjustment for other subscales, the final model for ADHD, contained hyperactivity/inattention and impact symptoms only and had a sensitivity of 91% and specificity of 90%; (AUC) = 0.94 (95% CI, 0.90–0.97). The final model for ASD was composed of all subscales except the ‘peer problems’ scales, indicating of the complexity of behavioural difficulties that may accompany ASD. A threshold of 0.03 produced model sensitivity and specificity of 79% and 93% respectively; AUC = 0.90 (95% CI, 0.86–0.95). The results support changes to DSM-5 removing exclusivity clauses.     

A pilot study: differential effects of methylphenidate-OROS on working memory and attention functions in children with attention-deficit/hyperactivity disorder with and without behavioural comorbidities

To examine the effects of methylphenidate-OROS (MPH-OROS) on working memory (WM) and attention functions in children with attention-deficit hyperactivity disorder (ADHD), and to investigate whether there is a differential effect in ADHD children with (ADHD+) and without (ADHD-) behavioural comorbidities. Participants included a clinic referred sample of 12 stimulant na?ve school-aged children with a diagnosis of combined ADHD according to the DSM-IV criteria (6 ADHD+, 6 ADHD-), and 11 healthy children. A neuropsychological protocol was applied at three different moments: before treatment, after one those of MPH-OROS, and after one month of MPH-OROS daily treatment. The protocol was simultaneously administered to the control group. Initial differences in attention parameters between na?ve children with ADHD and the control group disappeared after the first dose of MPH-OROS. For WM, one month of daily treatment was necessary to achieve this pattern of results. Both ADHD groups (ADHD+ and ADHD-) showed these differences, but there was a greater improvement in (ADHD-). MPH-OROS had an immediate effect on attention deficits, but long-term treatment was needed to improve WM to the level of healthy subjects. The presence of comorbid behavioural conditions determined a less robust response in neuropsychological performance to stimulant treatment.     

Interval Timing Deficits Assessed by Time Reproduction Dual Tasks as Cognitive Endophenotypes for Attention-Deficit/Hyperactivity Disorder

The literature has suggested timing processing as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD); however, whether the subjective internal clock speed presented by verbal estimation and limited attention capacity presented by time reproduction could be endophenotypes for ADHD is still unknown. We assessed 223 youths with DSM-IV ADHD (age range: 10-17 years), 105 unaffected siblings, and 84 typically developing (TD) youths using psychiatric interviews, intelligence tests, verbal estimation and time reproduction tasks (single task and simple and difficult dual tasks) at 5-second, 12-second, and 17-second intervals. We found that youths with ADHD tended to overestimate time in verbal estimation more than their unaffected siblings and TD youths, implying that fast subjective internal clock speed might be a characteristic of ADHD, rather than an endophenotype for ADHD. Youths with ADHD and their unaffected siblings were less precise in time reproduction dual tasks than TD youths. The magnitude of estimated errors in time reproduction was greater in youths with ADHD and their unaffected siblings than in TD youths, with an increased time interval at the 17-second interval and with increased task demands on both simple and difficult dual tasks versus the single task. Increased impaired time reproduction in dual tasks with increased intervals and task demands were shown in youths with ADHD and their unaffected siblings, suggesting that time reproduction deficits explained by limited attention capacity might be a useful endophenotype of ADHD.     

Time Course Analysis of Motor Excitability in a Response Inhibition Task According to the Level of Hyperactivity and Impulsivity in Children with ADHD

Short interval intracortical inhibition (SICI) of motor cortex, measured by transcranial magnetic stimulation (TMS) in a passive (resting) condition, has been suggested as a neurophysiological marker of hyperactivity in attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to determine motor excitability in a go/nogo task at stages of response preparation, activation and suppression in children with ADHD, depending on the level of hyperactivity and impulsivity. Motor evoked potentials were recorded in 29 typically developing children and 43 children with ADHD (subdivided in two groups with higher and lower levels of hyperactivity/impulsivity; H/I-high and H/I-low). In the H/I-high group, SICI was markedly reduced in the resting condition and during response preparation. Though these children were able to increase SICI when inhibiting a response, SICI was still reduced compared to typically developing children. Interestingly, SICI at rest and during response activation were comparable, which may be associated with their hypermotoric behaviour. In the H/I-low group, response activation was accompanied by a pronounced decrease of SICI, indicating reduced motor control in the context of a fast motor response. In summary, different excitability patterns were obtained for the three groups allowing a better understanding of dysfunctional response activation and inhibition processes within the motor cortex in children with ADHD.     

Epidemiology of ADHD in Chilean children and adolescents

ADHD prevalence, associated factors, comorbidity and service use are reported for a sample of 1,558 children and adolescents, belonging to four provinces in Chile. The sample is weighted in each step for selection bias. Psychiatric disorders and impairment are assessed with computerized in-home DISC-IV interviews, and a questionnaire regarding socioeconomic and family variables and service use. Estimates of prevalence rates are obtained by means of STATA 11.0 software, with complex sample design. Multivariate logistic regression is used to determine which factors were the best predictors for mental disorders. Participation rate is 82.4 %. The prevalence of ADHD is 10 %, and the most prevalent subtype is the hyperactive/impulsive, with no gender differences. Both hyperactive/impulsive and combined subtypes are more prevalent in children 4–11 than in adolescents. The most prevalent comorbidities are anxiety disorders and oppositional disorder. Anxiety is the more prevalent comorbid disorder in girls and correlated with a combined subtype. Perception of good family functioning, adolescent age and school dropout have a negative association with ADHD diagnosis, while maltreatment shows a positive correlation. Over 50 % of children and adolescents diagnosed with ADHD have used services in the last year. This is the first comprehensive community study of psychiatric disorders in children and adolescents in a South American country. It yields information for child and adolescent mental health programmes in Chile and contributes to cross-cultural epidemiological research.     

Parental efficacy and child behavior in a community sample of children with and without attention-deficit hyperactivity disorder (ADHD)

Most studies of attention-deficit hyperactivity disorder (ADHD) youth have obtained data from the perspective of either children or parents, but not both simultaneously. The purpose of this study was to examine child and parent perspectives on parenting in a large community-based sample of children with and without ADHD. We identified children in grades 4?C6 and their parents through surveys administered to a random sample of public schools. We used multivariable logistic regression to determine independent associations between child and parent characteristics and the presence of ADHD while controlling for covariates and clustering by school. Sufficient data were achieved for 2,509 child/parent dyads. Ten percent of youths (n?=?240) had been diagnosed with ADHD. Compared with those without ADHD, those with ADHD were more commonly male (67.9 vs. 48.0?%, p?<?.001) and age 12 or over (16.3 vs. 10.3?%). After adjusting for covariates and clustering, compared to children without ADHD, children with ADHD were significantly more likely to report lower self-regulation (OR?=?0.68, 95?% CI?=?0.53, 0.88) and higher levels of rebelliousness (OR?=?2.00, 95?% CI?=?1.52, 2.69). Compared with parents whose children did not have ADHD, parents of children with ADHD rated their overall parental efficacy substantially lower (OR?=?0.23, 95?% CI?=?0.15, 0.33). However, child assessment of parenting style was similar by ADHD. Despite the internal challenges community-based youth with ADHD face, many parents of ADHD youth exhibit valuable parental skills from the perspective of their children. Feedback of this information to parents may improve parental self-efficacy, which is known to be positively associated with improved ADHD outcomes.     

Discriminating between ADHD adults and controls using independent ERP components and a support vector machine: a validation study

Background

There are numerous event-related potential (ERP) studies in relation to attention-deficit hyperactivity disorder (ADHD), and a substantial number of ERP correlates of the disorder have been identified. However, most of the studies are limited to group differences in children. Independent component analysis (ICA) separates a set of mixed event-related potentials into a corresponding set of statistically independent source signals, which are likely to represent different functional processes. Using a support vector machine (SVM), a classification method originating from machine learning, this study aimed at investigating the use of such independent ERP components in differentiating adult ADHD patients from non-clinical controls by selecting a most informative feature set. A second aim was to validate the predictive power of the SVM classifier by means of an independent ADHD sample recruited at a different laboratory.

Methods

Two groups of age-matched adults (75 ADHD, 75 controls) performed a visual two stimulus go/no-go task. ERP responses were decomposed into independent components, and a selected set of independent ERP component features was used for SVM classification.

Results

Using a 10-fold cross-validation approach, classification accuracy was 91%. Predictive power of the SVM classifier was verified on the basis of the independent ADHD sample (17 ADHD patients), resulting in a classification accuracy of 94%. The latency and amplitude measures which in combination differentiated best between ADHD patients and non-clinical subjects primarily originated from independent components associated with inhibitory and other executive operations.

Conclusions

This study shows that ERPs can substantially contribute to the diagnosis of ADHD when combined with up-to-date methods.     

Switch Function and Pathological Dissociation in Acute Psychiatric Inpatients

Swift switching, along with atypical ability on updating and inhibition, has been found in non-clinical dissociators. However, whether swift switching is a cognitive endophenotype that intertwines with traumatisation and pathological dissociation remains unknown. Unspecified acute psychiatric patients were recruited to verify a hypothesis that pathological dissociation is associated with swift switching and traumatisation may explain this relationship. Behavioural measures of intellectual function and three executive functions including updating, switching and inhibition were administered, together with standardised scales to evaluate pathological dissociation and traumatisation. Our results showed superior control ability on switching and updating in inpatients who displayed more symptoms of pathological dissociation. When all three executive functions were entered as predictors, in addition to intellectual quotient and demographic variables to regress upon pathological dissociation, switching rather than updating remained the significant predictor. Importantly, the relationship between pathological dissociation and switching became non-significant when the effect of childhood trauma were controlled. The results support a trauma-related switching hypothesis which postulates swift switching as a cognitive endophenotype of pathological dissociation; traumatisation in childhood may explain the importance of swift switching.     

Shared Cognitive Impairments and Aetiology in ADHD Symptoms and Reading Difficulties

BackgroundTwin studies indicate that the frequent co-occurrence of attention deficit hyperactivity disorder (ADHD) symptoms and reading difficulties (RD) is largely due to shared genetic influences. Both disorders are associated with multiple cognitive impairments, but it remains unclear which cognitive impairments share the aetiological pathway, underlying the co-occurrence of the symptoms. We address this question using a sample of twins aged 7–10 and a range of cognitive measures previously associated with ADHD symptoms or RD.MethodsWe performed multivariate structural equation modelling analyses on parent and teacher ratings on the ADHD symptom domains of inattention and hyperactivity, parent ratings on RD, and cognitive data on response inhibition (commission errors, CE), reaction time variability (RTV), verbal short-term memory (STM), working memory (WM) and choice impulsivity, from a population sample of 1312 twins aged 7–10 years.ResultsThree cognitive processes showed significant phenotypic and genetic associations with both inattention symptoms and RD: RTV, verbal WM and STM. While STM captured only 11% of the shared genetic risk between inattention and RD, the estimates increased somewhat for WM (21%) and RTV (28%); yet most of the genetic sharing between inattention and RD remained unaccounted for in each case.ConclusionWhile response inhibition and choice impulsivity did not emerge as important cognitive processes underlying the co-occurrence between ADHD symptoms and RD, RTV and verbal memory processes separately showed significant phenotypic and genetic associations with both inattention symptoms and RD. Future studies employing longitudinal designs will be required to investigate the developmental pathways and direction of causality further.     

The Relationship between Stroop and Stop-Signal Measures of Inhibition in Adolescents: Influences from Variations in Context and Measure Estimation

The Stroop and stop-signal tasks are commonly used to index prepotent response inhibition in studies of cognitive development and individual differences. Inhibitory measures from the two tasks have been derived using a variety of methods. Findings of low inter-correlations amongst these measures have been interpreted as evidence for different kinds of inhibitory functions. Our previous study found Stroop and stop-signal accuracy measures to be uncorrelated and they loaded on different inhibitory components in a principal component analysis. The present study examined whether this finding is replicated across different task contexts, derived measures, and methods of derivation. Adolescents (N = 247) were administered a number-quantity Stroop and word and number stop-signal tasks. For each stop-signal task, inhibitory efficiency was estimated using a stop-signal reaction time measure estimated with the central versus the integration methods. For the Stroop interference task, inhibitory efficiency was indexed by reaction time measures (including inverse efficiency scores) generated from difference scores and regression residuals, and delta-plot slopes. The reaction time measures from the two tasks were generally not correlated. The only exception was that Stroop inhibitory ability, indexed by Stroop errors, was related to stop-signal inhibitory efficiency, indexed by stop-signal reaction time. These findings are consistent with previous findings suggesting that measures from the Stroop and stop-signal tasks are influenced by different underlying processes. The impact of variations in dependent measure derivation on the resulting reliabilities of Stroop and stop-signal measures and on observed correlations between them were examined. Variables that may have contributed to the null findings are discussed.     

Comorbidity and continuity of attention deficit hyperactivity disorder (ADHD) from childhood to adolescence in Turkey

The aim of this study was to examine clinical outcomes, psychiatric comorbidity and neuropsychological characteristics in Turkish adolescents with an attention deficit hyperactivity disorder (ADHD) diagnosis in childhood. A total of 45 children with ADHD diagnosis and 28 children with a psychiatric diagnosis other than ADHD in a 1-year cohort of 7–10-year-olds were reevaluated 6 years later using Schedule for Affective Disorders and Schizophrenia for School-Age Children Present and Lifetime version and Wechsler Intelligence Scale for Children-Revised and Stroop Test TBAG version. This study shows that the clinical outcomes and the comorbidity patterns for ADHD from childhood to adolescence in Turkey are similar to reported rates in the Western countries. In the ADHD group, 75.6 % still has impairing ADHD symptoms and 46.6 % has comorbid psychiatric disorders. The main difference is anxiety disorders being the most common comorbid disorders (37.8 %) in Turkish ADHD youth. These findings stress the high comorbidity associated with ADHD and support the importance of assessment and treatment for ADHD and comorbidities during adolescence.     

Attention-deficit/hyperactivity disorder and alexithymia: a pilot study

Although the relationship between alexithymia and psychopathology has been studied extensively in adults, research is lacking on alexithymia in childhood psychopathology. The aim of this study was to investigate the relationship between alexithymia and attention-deficit/hyperactivity disorder (ADHD). The Italian version of the Alexithymia Questionnaire for Children was administered to a sample of 50 children with a DSM-IV diagnosis of ADHD, as assessed by means of the K-SADS PL, and to 100 healthy, age- and sex-matched children without ADHD. The total alexithymia score as well as the difficulty in identifying feelings (DIF) and externally oriented thinking factors were significantly associated with ADHD. The total alexithymia score, the DIF, and the difficulty in describing feelings factors were also significantly associated with symptoms of hyperactivity/impulsivity. No significant relationship between alexithymia and inattentiveness symptoms emerged. Results provide preliminary data on the relationship between alexithymia and ADHD. Findings point to an association between difficulty in identifying emotions and hyperactivity/impulsivity. Future studies conducted on larger patient samples, as well as longitudinal designs, are warranted to confirm our findings.     

The effect of polyphenolic extract from pine bark, Pycnogenol on the level of glutathione in children suffering from attention deficit hyperactivity disorder (ADHD)

Attention deficit hyperactivity disorder (ADHD) belongs to the neurodevelopmental disorders characterized by impulsivity, distractibility and hyperactivity. In the pathogenesis of ADHD genetic and non-genetic factors play an important role. It is assumed that one of non-genetic factors should be oxidative stress. Pycnogenol, an extract from the pine bark, consists of bioflavonoids, catechins, procyanidins and phenolic acids. Pycnogenol acts as powerful antioxidant, chelating agent; it stimulates the activities of some enzymes, like SOD, eNOS, and exhibits other biological activities. AIM: The aim of this randomized, double-blind, placebo-controlled trial was to investigate the influence of administered Pycnogenol or placebo on the level of reduced (GSH) and oxidized (GSSG) glutathione in children suffering from ADHD and on total antioxidant status (TAS). This is the first investigation of the redox glutathione state in relation to ADHD. RESULTS: One month of Pycnogenol administration (1 mg/kg body weight/day) caused a significant decrease in GSSG and a highly significant increase in GSH levels as well as improvement of GSH/GSSG ratio in comparison to a group of patients taking a placebo. TAS in children with ADHD was decreased in comparison with reference values. Pycnogenol administration normalizes TAS of ADHD children.     

Analysis of Personal and Family Factors in the Persistence of Attention Deficit Hyperactivity Disorder: Results of a Prospective Follow-Up Study in Childhood

Objectives

To study the course of ADHD during childhood and analyze possible personal and family predictor variables of the results.

Method

Sixty-one children with ADHD who were between 6 and 12 years old at the baseline assessment were evaluated 30 months later (mean age at baseline: 8.70 ± 1.97; mean age at follow-up: 10.98 ± 2.19). Status of ADHD in follow-up was identified as persistent (met DSM-IV-TR criteria according to parents’ and teachers’ ratings), contextually persistent (met ADHD criteria according to one informant, and there was functional impairment) and remitted ADHD (with subthreshold clinical symptomatology). Associated psychological disorders of the three groups were analyzed in the follow-up with the Conners'' Rating Scales. The groups were compared on ADHD characteristics (symptoms of ADHD and impairment), child psychopathology, executive functioning (EF; inhibition, working memory) and parenting characteristics (parental stress and discipline styles) at baseline.

Results

At the follow-up, 55.7% of the children continued to meet the DSM-IV-TR criteria for ADHD, 29.5% showed contextual persistence, and 14.8% presented remission of the disorder. The persistent and contextually persistent ADHD groups showed more associated psychological disorders. Inattention, oppositional problems, cognitive problems and impairment at baseline distinguished the remitted ADHD children from the persistent and contextually persistent ADHD children. Moreover, the persistent groups had significantly more emotional liability and higher parental stress than the group in remission, while no differences in EF where found among the groups.

Conclusions

ADHD children continue to present symptoms, as well as comorbid psychological problems, during adolescence and early adulthood. These findings confirm that persistence of ADHD is associated with child psychopathology, parental stress and impairment in childhood.