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Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset mental disorder, demonstrates genetical effects, and is characterized by attention deficit, hyperactivity, and impulsivity. While ADHD was previously only considered a childhood disorder, longitudinal studies over the past decades have proven that in a significant number of cases, the symptoms of the disorder can also be detected in adulthood, and therefore affects 2-4% of the adult population. In Hungary, adult ADHD programs started about 20 years ago and has been able to provide help to many adults living with ADHD. However, this form of care needs further development in many aspects and suffers from capacity deficits at the national level. On July 4-6, 2023 we organized a CME course on adult ADHD at the Department of Psychiatry and Psychotherapy Semmelweis University. The objective of this course was to deepen the knowledge of participants and alleviate care difficulties in the long term through the sharing of information and good practices. As part of this, a narrative review was written, which touches on the current issues of diagnosing and treating ADHD in adults.

Our aim was to delineate the electrophysiological basis of dysfunctional inhibitory control of adult ADHD via investigating the anteriorization of the P3 component of the event-related brain response associated with the NoGo task condition (i.e., NoGo anteriorization, NGA). NGA is a neurophysiological measure of brain topography for cognitive response control, which indexes an overall shift of the brain's electrical activity in anterior direction towards the prefrontal areas. While the NoGo P3 received considerable attention in the adult ADHD literature, the brain topography of this component, which reflects the inhibitory process, remains largely unaddressed. EEG recordings were obtained during a Go/NoGo task from 51 subjects (n = 26 adult patients with ADHD, n = 25 healthy controls) using a high-density, 128-channel BioSemi ActiveTwo recording system. ADHD patients had significantly lower P3 NGA response compared to controls. The decrease in NGA was related to impulsivity scores as measured by the Conners' Adult ADHD Rating Scale: patients with higher impulsivity scores had significantly lower NGA. Treatment with stimulant medication, as compared to the lack of such treatment, was associated with a correction of the lower NGA response in ADHD patients. The current study revealed a lower NGA in adult ADHD, a finding which is consistent with the inhibitory control and frontal lobe dysfunctions described in the disorder. Our finding of the inverse relationship between NGA and impulsivity suggests that clinically more severe impulsivity is linked to a more pronounced frontal dysfunction in adult ADHD subjects., (© 2023. The Author(s).)

Decreased gamma activity has been reported both in children and adults with attention deficit/hyperactivity disorder (ADHD). However, while ADHD is a lifelong neurodevelopmental disorder, our insight into the associations of spontaneous gamma band activity with age is limited, especially in adults. Therefore, we conducted an explorative study to investigate trajectories of resting gamma activity in adult ADHD patients (N = 42) versus matched healthy controls (N = 59). We investigated the relationship of resting gamma activity (30-48 Hz) with age in four right hemispheric electrode clusters where diminished gamma power in ADHD had previously been demonstrated by our group. We found significant non-linear association between resting gamma power and age in the lower frequency gamma 1 range (30-39 Hz) in ADHD as compared to controls in all investigated locations. Resting gamma 1 increased with age and was significantly lower in ADHD than in control subjects from early adulthood. We found no significant association between gamma activity and age in the gamma 2 range (39-48 Hz). Alterations of gamma band activity might reflect altered cortical network functioning in adult ADHD relative to controls. Our results reveal that abnormal gamma power is present at all ages, highlighting the lifelong nature of ADHD. Nonetheless, longitudinal studies are needed to confirm our results., (© 2021. The Author(s).)

Background: Children with attention-deficit/hyperactivity disorder (ADHD) often demonstrate sensory processing difficulties in the form of altered sensory modulation, which may contribute to their symptomatology. Our objective was to investigate the neurophysiological correlates of sensory processing deficits and the electrophysiological characteristics of early information processing in adult ADHD, measured by the P1 event-related potential (ERP)., Methods: We obtained ERPs during a Go/NoGo task from 26 adult patients with ADHD and 25 matched controls using a high-density 128-channel BioSemi ActiveTwo recording system., Results: ADHD patients had a significantly reduced P1 component at occipital and inferotemporal scalp areas compared to controls. The reduction was associated with inattention and hyperactivity symptom severity, as measured by the Conners' Adult ADHD Rating Scale. ADHD patients with higher inattention scores had significantly smaller P1 amplitudes at posterior scalp sites, while higher hyperactivity scores were associated with higher P1 amplitudes., Conclusions: Deficits in early sensory processing, as measured by the P1 ERP component, are present in adult ADHD patients and are associated with symptom severity. These findings are suggestive of bottom-up cognitive deficits in ADHD driven by impairments in early visual processing, and provide evidence that sensory processing problems are present at the neurophysiological level in this population.

Objectives: To delineate task-free gamma activity in adult ADHD and healthy control subjects based on high-density EEG recordings. Relationship of gamma activity with symptom severity was also examined, since gamma activity is considered to be an index of network functions in the brain that underlie higher-order cognitive processes. Methods: Spontaneous EEG was recorded in adult ADHD subjects ( N  = 42; 25 methylphenidate-naïve and 17 on methylphenidate treatment) and controls ( N  = 59) with eyes open. EEG absolute power gamma was investigated in the gamma 1 (30.25-39 Hz) and gamma 2 (39.25-48 Hz) frequency bands. Results: Gamma 1 and gamma 2 activity was diminished in ADHD compared with healthy control subjects. The difference between ADHD and controls was the most pronounced in the right centroparietal region for both gamma 1 and gamma 2 . Inverse associations were found between gamma 1 and gamma 2 activity and ADHD symptoms in centroparietal scalp regions. Conclusions: Gamma activity is reduced in adult ADHD, and the reduction has a predominantly right centroparietal distribution. Our findings are consistent with childhood ADHD literature with respect to diminished posterior gamma activity in patients, which may reflect altered dorsal attention network functions. Gamma abnormalities might provide a link between neurophysiological functioning and neuropsychological deficiencies, thereby offering an opportunity to investigate the neurobiological mechanisms that underlie the clinical symptoms of ADHD.

Deficits in error-processing are postulated in core symptoms of ADHD. Our goal was to investigate the neurophysiological basis of abnormal error-processing and adaptive adjustments in ADHD, and examine whether error-related alterations extend beyond traditional Regions of Interest (ROIs), particularly to those involved in adaptive adjustments, such as the Salience Network system. We obtained event-related potentials (ERPs) during a Go/NoGo task from 22 adult-ADHD patients and 29 matched healthy controls using a high-density 256-electrode array. Error-related ERPs with error-negativity (ERN) and error-positivity (Pe) served as probes of error-processing. In ADHD patients both ERN and Pe were significantly reduced, and the reduction was associated with core psychopathological symptoms. The ERP-attenuation was prominent not only at traditional ROI-electrodes but across many other brain areas, with a distinctive subset of group-differences and symptom-correlations manifested at temporo-parietal sites, with right-lateralization. Source-localization uncovered two neural-sources for the error-related ERPs: one in the cingulate cortex near midline, which was present in both groups; and one in the right insular cortex, which was present only in the control group. The neural patterns of impairments may be the result of coexisting deficits in the dorsal midline error-processing brain network involved in "error-processing proper" and the right-lateralized temporo-parietal salience network involved in the evaluation of significance of the error-signals. Our source-localization findings potentially identify a missing link between the previously reported structural change, i.e., reduced insular volume, and the well-established behavioral deficits in ADHD.

The authors' aim was to investigate the modulation of event-related potentials (ERPs) by the affective content of stimuli in adult attention deficit hyperactivity disorder (ADHD) patients during error monitoring. By obtaining ERPs from 26 adult ADHD patients and 14 healthy controls in an emotional go/no-go task, the authors investigated two error-related ERP components, the error-related negativity (ERN) and error positivity (Pe). In ADHD patients, the ERN amplitude decreased for negative stimuli after failed response inhibition ("no-go response") and Pe amplitude decreased for neutral stimuli compared with the controls. These findings suggest that ADHD patients differ from controls both in the early and in the later stages of error processing.

Aberrations in early-developing bottom-up processes, such as stimulus-driven response preparation, are thought to play a critical role in the onset of ADHD, and in its persistence over time. Electrophysiology offers a unique tool to gain insight into response preparation, since response preparation has been associated with distinctive ERP changes, including negative potential-shifts which occur predominantly over frontal brain areas. We examined response-preceding negative potential shifts (RPNS) as a probe of response-preparation in adult ADHD patients by obtaining high-density event-related potentials from 33 ADHD and 29 matched healthy subjects during a Go/Nogo task using a 128-channel BioSemi recording-system. Compared to controls, ADHD patients showed enhancement of the RPNS in fronto-central brain regions in the Go condition during correct responses. This change was associated with poor performance in the Stroop incongruency-task: the greater the enhancement, the higher the proportion of errors. Moreover, the ERP-enhancement showed association with the severity of ADHD-symptoms; and with heightened response-variability. Thus, ADHD patients demonstrate neurophysiological alterations in response-preparation and response-preceding brain activity, suggestive of excessive activation of prefrontal neural circuits. Given the correlation with neuropsychological and psychopathological measures, these changes may constitute a pathway for core symptoms of ADHD, including premature and impaired response-preparation and motor-hyperactivity., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Introduction: According to a recent assessment the prevalence of adult attention-deficit/hyperactivity disorder (ADHD) was 1.5% in the Hungarian adult population (1), which is in line with previous results indicating that ADHD is a disorder of high prevalence. The core symptoms, including the attention deficit, the hyperactivity and impulsivity are all characteristics that have a significant impact on cognitive functions. Our review focuses on event-related potentials of patients suffering from adult ADHD. With information gained from electrophysiological measurement, our goal is to give an overview of the process leading to a functional impairment based on the available literature., Method: PubMed and Medline search engines were used in order to identify all relevant articles, published between 1993 and 2010. For the purpose of the current paper we reviewed publications summarizing results of clinical studies., Results: With regard to evoked potentials reflecting early sensorial information processing a significant difference between ADHD and control subjects was detected in the auditory N2 and P2, and visual N2 components. The P300 component, which is independent of modality, was significantly lower in ADHD patients compared to the control group. Similar results were reported with regard to error related negativity (ERN)., Conclusion: Since electrophysiological research investigating event-related evoked potientials in adults suffering from ADHD have come to the focus of scientific interest only recently, the amount of literature available is relatively limited. Considering that all three core symptoms of the disorder have a significant impact on both information processing and on concomitant cognitive functions, patients with ADHD should be divided into subgroups based on their neuropsychologically measured dominant symptoms.