Executive and Daily Life Functioning Influence the Relationship Between ADHD and Mood Symptoms in University Students.

Objectives: Many studies have indicated a close relationship between ADHD and mood symptoms in university students. In the present study, we explore the role of daily functional impairments and executive functioning in the ADHD-mood relationship. Method: A total of 343 adults (126 males) filled out (a) the Conners' Adult ADHD Rating Scale, (b) the Depression Anxiety and Stress Scale, (c) the Weiss Functional Impairment Rating Scale, and (d) the Executive Function Index Scale. Results: The correlation between mood symptoms and ADHD was .48 (moderate correlation) and dropped to .15 (weak correlation) when controlling for functional problems and executive functioning. Hierarchical regression analyses showed that both functional impairments and executive functioning significantly explained 42% to 53% of the variance of mood symptoms. The addition of ADHD symptoms to the model slightly increased the explained mood variance by only 1%. Conclusion: These findings underline the role of experienced difficulties in triggering mood symptoms in ADHD symptomatology.

Error monitoring and daily life executive functioning.

Error monitoring during task execution is reflected in post-error slowing (PES), which refers to the tendency to slow down performance after making an error in order to prevent future mistakes. The key question of the present study is whether poor error monitoring (reduced magnitude of PES) has negative consequences for daily life executive function skills, as well as functioning in different life settings such as work, family, social, and academic settings. Eighty-five university students performed a lexical decision task and completed The Executive Function Index Scale (EFI), and the Weiss Functional Impairments Rating Scale (WFIRS). Individual academic achievement was measured using the Grade Point Average. Statistical analysis revealed that a decreased magnitude of PES was weakly associated with less efficient planning (one of the executive functions). Results suggest that error monitoring, as measured by PES, was not associated with functioning in a naturalistic environment, but could be interpreted to some extent as an experimental marker of planning in daily life executive functioning.

Post-error adjustments and ADHD symptoms in adults: The effect of laterality and state regulation.

Evidence is accumulating that individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) do not adjust their responses after committing errors. Post-error response adjustments are taken to reflect, among others, error monitoring that is essential for learning, flexible behavioural adaptation, and achieving future goals. Many behavioural studies have suggested that atypical lateral brain functions and difficulties in allocating effort to protect performance against stressors (i.e., state regulation) are key factors in ADHD. Whether these factors contribute to the absence of post-error response adjustments in ADHD is unknown. The aim of the present study is to investigate the contribution of the left and right hemispheres and the deficiency in effort allocation to deviant post-error processing in adults with high ADHD symptoms. From a pool of 87 university students, two groups were formed: a group with higher (n=30) and a group with lower (n=26) scores on the ADHD index subscale of the Conners' Adult ADHD Rating Scales. The groups performed a lateralized lexical decision task with a fast and slower stimulus presentation rate. Post-error slowing and post-error response accuracy to stimuli presented in the left and right visual field were measured in each stimulus presentation rate. Results indicated that subjects with the lower ADHD scores slowed down and improved their response accuracy after errors, especially when stimuli were presented in the right visual field at the slower rate. In contrast, subjects with the higher ADHD scores showed no post-error adjustments. Results suggest that during lexical decision performance, impaired error processing in adults with ADHD is associated with affected ability of the left hemisphere to compensate for errors, especially when extra effort allocation is needed to meet task demands.

Linking state regulation, brain laterality, and self-reported attention-deficit/hyperactivity disorder (ADHD) symptoms in adults.

INTRODUCTION: Many clinical studies have shown that performance of subjects with attention-deficit/hyperactivity disorder (ADHD) is impaired when stimuli are presented at a slow rate compared to a medium or fast rate. According to the cognitive-energetic model, this finding may reflect difficulty in allocating sufficient effort to regulate the motor activation state. Other studies have shown that the left hemisphere is relatively responsible for keeping humans motivated, allocating sufficient effort to complete their tasks. This leads to a prediction that poor effort allocation might be associated with an affected left-hemisphere functioning in ADHD. So far, this prediction has not been directly tested, which is the aim of the present study. METHOD: Seventy-seven adults with various scores on the Conners' Adult ADHD Rating Scale performed a lateralized lexical decision task in three conditions with stimuli presented in a fast, a medium, and a slow rate. The left-hemisphere functioning was measured in terms of visual field advantage (better performance for the right than for the left visual field). RESULTS: All subjects showed an increased right visual field advantage for word processing in the slow presentation rate of stimuli compared to the fast and the medium rate. Higher ADHD scores were related to a reduced right visual field advantage in the slow rate only. CONCLUSIONS: The present findings suggest that ADHD symptomatology is associated with less involvement of the left hemisphere when extra effort allocation is needed to optimize the low motor activation state.

Brain lateralization and self-reported symptoms of ADHD in a population sample of adults: a dimensional approach.

Many clinical studies reported a compromised brain lateralization in patients with Attention-Deficit/Hyperactivity Disorder (ADHD) without being conclusive about whether the deficit existed in the left or right hemisphere. It is well-recognized that studying ADHD dimensionally is more controlled for comorbid problems and medication effects, and provides more accurate assessment of the symptoms. Therefore, the present study applied the dimensional approach to test the relationship between brain lateralization and self-reported ADHD symptoms in a population sample. Eighty-five right-handed university students filled in the Conners' Adult ADHD Rating Scales and performed a lateralization reaction time task. The task consists of two matching conditions: one condition requires nominal identification for letters tapping left hemisphere specialization (Letter Name-Identity condition) and the other one requires physical and visuospatial identification for shapes tapping right hemisphere specialization (Shape Physical-Identity condition). The letters or shapes to be matched are presented in left or right visual field of a fixation cross. For both task conditions, brain lateralization was indexed as the difference in mean reaction time between left and right visual field. Linear regression analyses, controlled for mood symptoms reported by a depression, anxiety, and stress scale, showed no relationship between the variables. These findings from a population sample of adults do not support the dimensionality of lateralized information processing deficit in ADHD symptomatology. However, group comparison analyses showed that subjects with high level of inattention symptoms close to or above the clinical cut-off had a reduced right hemisphere processing in the Shape Physical-Identity condition.

Self-Reported ADHD Symptoms and Interhemispheric Interaction in Adults: A Dimensional Approach.

The present study applied the dimensional approach to test whether self-reported symptoms of Attention Deficit/Hyperactivity Disorder (ADHD) in adults are associated with the speed of interhemispheric interaction. A sample of first grade students (N = 112) completed Conners' Adult ADHD Rating Scales and letter matching reaction time tasks. In the tasks, participants had to match a single target letter displayed below the fixation cross, either on left or right visual field, with one of two letters displayed above the fixation cross, one letter on each visual field. For each task, identical letters were presented either within the same visual field (within hemisphere condition) or across visual fields (across hemisphere condition). Interhemispheric interaction was indexed as the difference in mean reaction time between within and across hemisphere conditions. Comorbid problems such as depression, anxiety, and stress may affect task performance and are controlled for in this study. Findings indicated that self-reported ADHD symptomology, especially hyperactivity, in the presence of stress was weakly but significantly associated with fast interhemispheric interaction.

Visual orientation in hospitalized boys with early onset conduct disorder and borderline intellectual functioning.

The aim of the present study is to investigate visual orientation in hospitalized boys with severe early onset conduct disorder and borderline intellectual functioning. It is tested whether boys with the dual diagnosis have a stronger action-oriented response style to visual-cued go signals than the norm. To this end, boys with the dual diagnosis were compared with a peer control group on Posner's (1980) visual-spatial detection test. Here, on each trial, a visual cue points either in the direction of the location of a subsequent go signal (valid cue), or points in the opposite direction away from the location of the subsequent go signal (invalid cue). Findings indicated superior orientation (a strong action-oriented response style) of children with the dual diagnosis in valid-cued trials as well as in invalid-cued trials in both the left and the right visual hemifield. Findings were controlled for attention scores on the Child Behavior Checklist -Teacher Form and IQ scores.

Interference control in children with first episode major depression: a brief report.

The ability to deal with sources of conflict, that is, interference control, was evaluated in a group of 11 children with first episode Major Depression and a peer control group. To this end, the Eriksen and Schultz (1979) task was used. Here, the participant is presented with a stimulus that simultaneously activates two conflicting response channels: One response is activated by the instructions, whereas the other response is activated by elements in the array that strongly invite an alternative - yet incorrect - response. Findings provided no evidence for an undisturbed interference control nor impaired overall processing speed in children with first episode Major Depression.

Performance variability, impulsivity errors and the impact of incentives as gender-independent endophenotypes for ADHD.

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is one of the most common and highly heritable child psychiatric disorders. There is strong evidence that children with ADHD show slower and more variable responses in tasks such as Go/Nogo tapping aspects of executive functions like sustained attention and response control which may be modulated by motivational factors and/or state-regulation processes. The aim of this study was (1) to determine if these executive functions may constitute an endophenotype for ADHD; (2) to investigate for the first time whether known modulators of these executive functions may also be familial; and (3) to explore whether gender has an impact on these measures. METHODS: Two hundred and five children with ADHD combined type, 173 nonaffected biological siblings and 53 controls with no known family history of ADHD were examined using a Go/Nogo task in the framework of a multi-centre study. Performance-measures and modulating effects of event-rate and incentives were examined. Shared familial effects on these measures were assessed, and the influence of gender was tested. RESULTS: Children with ADHD responded more slowly and variably than nonaffected siblings or controls. Nonaffected siblings showed intermediate scores for reaction-time variability, false alarms and omission errors under fast and slow event-rates. A slower event-rate did not lead to reduced performance specific to ADHD. In the incentive condition, mean reaction-times speeded up and became less variable only in children with ADHD and their nonaffected siblings, while accuracy was improved in all groups. Males responded faster, but also committed more false alarms. There were no interactions of group by gender. CONCLUSIONS: Reaction-time variability and accuracy parameters could be useful neuropsychological endophenotypes for ADHD. Performance-modulating effects of incentives suggested a familially driven motivational dysfunction which may play an important role on etiologic pathways and treatment approaches for ADHD. The effects of gender were independent of familial effects or ADHD-status, which in turn suggests that the proposed endophenotypes are independent of gender.

Very low birth weight and attention deficit/hyperactivity disorder.

It is well recognized that reaction time performance of term-born children with a normal birth weight (NBW > 2500 g) who fulfill the DSM-IV criteria for attention deficit/hyperactivity disorder (ADHD) in the primary school age is sensitive for the presentation rate of stimuli. They have been found to perform more poorly in conditions of relatively slow event rates as compared with fast event rates. The purpose of the current study was to explore whether reaction time performance of children with very low birth weight (VLBW < 1500 g) with or without ADHD showed the same sensitivity for the factor presentation rate of stimuli compared to children with a normal birth weight plus ADHD. To this end, reaction time performance of four groups of children was compared on a Go/No-Go test with a fast presentation rate of 1 second and a slow presentation rate of 6 seconds. Groups were: children with VLBW plus ADHD, children with VLBW only, children born full term with normal birth weight (NBW >2500 g) plus ADHD, and children born full term without ADHD (the control group). Findings indicated that, compared to the non-ADHD groups, the groups with ADHD (NBW and VLBW) showed a more dramatic decline in their reaction time performance in the slow condition: a state regulation deficit. In addition, both groups showed a response inhibition deficit. No difference was found in reaction time performance between the groups of children with VLBW only and the control group.

Impulsive responses in children with conduct disorder and borderline intellectual functioning.

The study is designed to investigate response inhibition in children with conduct disorder and borderline intellectual functioning. To this end, children are compared to a normal peer control group using the Alertness test. The test has two conditions. In one condition, children are instructed to push a response button after a visual "go" signal is presented on the screen. In a second condition the "go" signal is preceded by an auditory signal, telling the child that a target stimulus will occur soon. Compared to the control group, the group carrying the dual diagnosis made many preliminary responses (responses before the presentation of the "go" signal), especially in the condition with an auditory signal. This impulsive response style was controlled for attention deficit/hyperactivity disorder characteristics of the children.

Attention and impulse control in children with borderline intelligence with or without conduct disorder.

This study was designed to investigate attention and impulse control in 21 boys with dual diagnoses of conduct disorder and borderline intelligence and in 19 boys with borderline intelligence only. Using the Continuous Performance Test A-not-X, it appeared that children with the dual diagnosis made substantially more errors reflecting poor impulse control than the other group. The frequency of these errors was associated with scores on Impulsiveness, Aggression, and Delinquency subscales of the Child Behavior Checklist (Teacher Version). Also, the group with the dual diagnosis showed signs of a deficit in attention.

Sustained attention in major unipolar depression.

Patients suffering from a major unipolar depression (n=17) and a normal control group (n=17) were compared on a noninterrupted vigilance task with a duration of 36 min. The performance decrement over time of the depressed group was indicative of a deficit in sustained attention.

Reaction time, inhibition, working memory and 'delay aversion' performance: genetic influences and their interpretation.

BACKGROUND: For candidate endophenotypes to be useful for psychiatric genetic research, they first of all need to show significant genetic influences. To address the relative lack of previous data, we set to investigate the extent of genetic and environmental influences on performance in a set of theoretically driven cognitive-experimental tasks in a large twin sample. We further aimed to illustrate how test-retest reliability of the measures affects the estimates. METHOD: Four-hundred 7- to 9-year-old twin pairs were assessed individually on tasks measuring reaction time, inhibition, working memory and 'delay aversion' performance. Test-retest reliability data on some of the key measures were available from a previous study. RESULTS: Several key measures of reaction time, inhibition and working-memory performance indicated a moderate degree of genetic influence. Combining data across theoretically related tasks increased the heritability estimates, as illustrated by the heritability estimates of 60% for mean reaction time and 50% for reaction-time variability. Psychometric properties (reliability or ceiling effects) had a substantial influence on the estimates for some measures. CONCLUSIONS: The data support the usefulness of several of the variables for endophenotype studies that aim to link genes to cognitive and motivational processes. Importantly, the data also illustrate specific conditions under which the true extent of genetic influences may be underestimated and hence the usefulness for genetic mapping studies compromised, and suggest ways to address this.

ADHD deficit as measured in adolescent boys with a continuous performance task is related to antenatal maternal anxiety.

Antenatal maternal anxiety has been shown to be related to infant temperament, childhood disorders, and impulsivity in adolescence. This study prospectively investigated whether antenatal maternal anxiety is associated with performance on a continuous performance task. Sixty-four adolescents (mean age, 15 y; 34 boys, 30 girls) were examined with a computerized continuous performance task (CPT) measuring sustained attention. Results showed that the CPT performance of boys of mothers with high levels of state anxiety during the 12th to 22nd postmenstrual week of pregnancy declined as the task progressed: their processing speed became slower and the variability in their reaction times increased. The study controlled for the possible confounding influences of postnatal maternal anxiety, the parents' educational level, and intelligence. Establishing a link between antenatal maternal anxiety and an objective measure of sustained attention/self-regulation, our results extend the growing evidence for an association between antenatal maternal anxiety and the neurobehavioral development of the offspring up into adolescence.

Testing assumptions for endophenotype studies in ADHD: reliability and validity of tasks in a general population sample.

BACKGROUND: Advances in both genetic and cognitive-experimental studies on attention deficit hyperactivity disorder (ADHD) have opened new opportunities for cognitive endophenotype research. In such genetic designs the focus is on individual differences in characteristics, associated with ADHD, that can be measured reliably over time. Genetic studies that take a 'quantitative trait loci' approach hypothesise that multiple susceptibility genes contribute to a continuous dimension of ADHD symptoms. As an important initial step, we aimed to investigate the underlying assumptions that (1) key cognitive-experimental tasks indicate adequate test-retest reliability and (2) ADHD symptom scores in a general population sample are associated with performance on these tasks. METHODS: Forty-nine children were assessed on a go/no-go task and a reaction time task (the 'fast task') that included manipulations with event rate and incentives. The children were assessed twice, with a test-retest interval of two weeks. RESULTS: The majority of the task variables demonstrated moderate-to-good test-retest reliability. The correlations between teacher ratings of ADHD symptoms and key task variables were .4-.6: ADHD symptoms were associated with poor performance (especially high reaction time variability) in a slow baseline condition, whereas there was low or no association in conditions with a faster event rate or incentives. In contrast, no clear pattern of findings emerged based on parent ratings of ADHD symptoms. CONCLUSION: The data support the usefulness of the go/no-go and fast tasks for genetic studies, which require reliable and valid indices of individual differences. The overall pattern of associations between teacher ratings of ADHD symptoms and task variables is consistent with effects of event rate and incentives on performance, as predicted by the model of activation and arousal regulation. The lack of a clear pattern of findings with parent ratings of ADHD symptoms warrants further study.