Limited usefulness of neurocognitive functioning indices as predictive markers for treatment response to methylphenidate or neurofeedback@home in children and adolescents with ADHD.

Introduction: Earlier studies exploring the value of executive functioning (EF) indices for assessing treatment effectiveness and predicting treatment response in attention-deficit/hyperactivity disorder (ADHD) mainly focused on pharmacological treatment options and revealed rather heterogeneous results. Envisioning the long-term goal of personalized treatment selection and intervention planning, this study comparing methylphenidate treatment (MPH) and a home-based neurofeedback intervention (NF@Home) aimed to expand previous findings by assessing objective as well as subjectively reported EF indices and by analyzing their value as treatment and predictive markers. Methods: Children and adolescents (n = 146 in the per protocol sample) aged 7-13 years with a formal diagnosis of an inattentive or combined presentation of ADHD were examined. We explored the EF performance profile using the Conners Continuous Performance Task (CPT) and the BRIEF self-report questionnaire within our prospective, multicenter, randomized, reference drug-controlled NEWROFEED study with sites in five European countries (France, Spain, Switzerland, Germany, and Belgium). As primary outcome for treatment response, the clinician-rated ADHD Rating Scale-IV was used. Patients participating in this non-inferiority trial were randomized to either NF@home (34-40 sessions of TBR or SMR NF depending on the pre-assessed individual alpha peak frequency) or MPH treatment (ratio: 3:2). Within a mixed-effects model framework, analyses of change were calculated to explore the predictive value of neurocognitive indices for ADHD symptom-related treatment response. Results: For a variety of neurocognitive indices, we found a significant pre-post change during treatment, mainly in the MPH group. However, the results of the current study reveal a rather limited prognostic value of neurocognitive indices for treatment response to either NF@Home or MPH treatment. Some significant effects emerged for parent-ratings only. Discussion: Current findings indicate a potential value of self-report (BRIEF global score) and some objectively measured neurocognitive indices (CPT commission errors and hit reaction time variability) as treatment markers (of change) for MPH. However, we found a rather limited prognostic value with regard to predicting treatment response not (yet) allowing recommendation for clinical use. Baseline symptom severity was revealed as the most relevant predictor, replicating robust findings from previous studies.

Impact of the COVID-19 pandemic on mental health and family situation of clinically referred children and adolescents in Switzerland: results of a survey among mental health care professionals after 1 year of COVID-19.

The aim of this study was to assess the impact of the COVID-19 pandemic on mental well-being of clinically referred children and adolescents and on their families from the perspective of mental health care professionals in Switzerland during the first year of the pandemic. Psychiatrists and psychologists for children and adolescents participated in an anonymous survey conducted online in April/May 2021. The survey was completed by 454 mental health care professionals, most of them working in outpatient clinics for child and adolescent psychiatry or in independent practices. Most participants indicated an important increase of referrals for depression (86.8% of respondents), anxiety disorders (81.5%), crisis interventions (76.2%), psychosomatic disorders (66.1%), suicidality (63.8%), and behavioral addictions, e.g., excessive gaming (64.6%). In contrast, referrals or treatment demands for disorders such as autism spectrum disorder or psychosis showed no substantial change or a slight decrease, respectively. According to 69% of respondents, patients experienced the highest psychological burden in January/February/March 2021. Family problems very frequently reported by mental health professionals were parents' worries about loneliness/isolation of the child (49%), child's education and academic future (33%), increased media use due to missing options of recreational activities (37.6%), as well as multiple stresses of mothers (36.3%). To conclude, the pandemic has substantially changed the pattern of disorders and the number of clinical referrals of children and adolescents with mental health problems, which has serious consequences for the treatment supply in Switzerland.

Problematic use of digital media in children and adolescents with a diagnosis of attention-deficit/hyperactivity disorder compared to controls. A meta-analysis.

Objective: Problematic use of digital media and problematic use of the internet (PUI) in particular are growing problems in the general population. Moreover, studies have shown links between PUI and symptoms of attention-deficit/hyperactivity disorder (ADHD). This meta-analysis investigated whether children and adolescents with ADHD are more often affected by PUI compared to control groups. Method: Multiple databases (EBSCOhost, Pubmed) were reviewed. Studies were eligible if individuals (aged 6-18 years) were diagnosed with ADHD, assessed on PUI-related measures, and compared to non-clinical or/and clinical controls without a diagnosis of ADHD. Out of 3,859 identified studies, 14 studies assessing 2,488 participants met all inclusion criteria. Four meta-analyses examining time-based and scale-based measures, different informants and non-clinical vs. clinical controls using random-effects models were performed. Funnel plots were used to investigate publication bias. Results: The analyses revealed significantly more severe PUI in individuals with ADHD compared to controls, both when PUI was assessed via rating scale (scaled-based) and via units for time (time-based measures). Different informants (self- vs. parent-rating) had no impact on results. Differences in PUI between groups with ADHD and non-clinical controls were significant, whereas differences between ADHD and clinical controls were not. Due to the high heterogeneity observed and the small sample sizes, these latter findings should be interpreted cautiously. Conclusion: Children and adolescents with ADHD show more severe PUI compared to non-clinical controls without ADHD. However, the small number of studies does not allow for a systematic comparison between ADHD and groups with other psychopathologies.

The Impact of the COVID-19 Pandemic on Mental Health Care of Children and Adolescents in Switzerland: Results of a Survey among Mental Health Care Professionals after One Year of COVID-19.

BACKGROUND: To assess the impact of the COVID-19 pandemic on treatment demand and supply in children and adolescents with mental disorders during the first year of the pandemic from the perspective of child and adolescent psychiatrists and psychologists in Switzerland. METHODS: The survey was conducted anonymously, in German or French and online in April/May 2021. Mental health professionals working in child and adolescent psychiatry, psychotherapy services or independent practices were contacted by email. RESULTS: N = 454 professionals completed the survey (176 child and adolescent psychiatrists and 276 psychologists). After an initial period of decreased demand during the lockdown in spring 2020, requests for treatment increased, considerably exceeding the demand pre-pandemic and reaching a peak in January/February/March 2021. The vast majority of professionals (78.2%) estimated that there was currently too little supply during the pandemic, which differed from the evaluation of the pre-pandemic situation (37%). A total of 65% of participants indicated that waiting time until the initiation of treatment increased during the pandemic, 41% reported their current workload to be somewhat higher and 44.5% much higher. CONCLUSIONS: For the first pandemic year, youth mental health professionals reported a large increase in the treatment demand and waiting time and a worrisome overload of treatment services.

Media use and emotional distress under COVID-19 lockdown in a clinical sample referred for internalizing disorders: A Swiss adolescents' perspective.

The COVID-19 outbreak has profoundly affected adolescents' life. Adolescents with pre-existing psychiatric disorders have been at particular risk of increased mental health problems and problematic media use. 178 patients, aged 12-18 years, referred before the COVID-19 outbreak to child and adolescent psychiatry, participated in an anonymous online survey on the impact of the lockdown on media use and mental well-being. The survey was conducted approximately one month after the first easing of restrictions following a six-week lockdown in Switzerland. Based on self-report, half of the patients had been diagnosed with internalizing disorders (ID; depression or anxiety disorder) and the other half with other disorders (non-ID, e.g. ADHD, autistic spectrum disorder). Patients with ID reported higher emotional distress during the lockdown, and a larger number of patients with ID indicated a deterioration of pre-existing symptoms compared to non-ID patients. Although more patients with ID than with non-ID indicated spending a large amount of time on social media, social media time per day in hours was not significantly higher in ID. Patients with ID indicated a higher impact of media use on well-being and mood in everyday life during the lockdown. Social media time was higher in worsened than in improved non-ID patients, while the opposite was found in ID patients, indicating a possible protective effect of media use at least for some ID patients. The results confirm positive as well as negative associations between mental health, emotional well-being and media use for adolescents with ID during the lockdown.

Personalized at-home neurofeedback compared to long-acting methylphenidate in children with ADHD: NEWROFEED, a European randomized noninferiority trial.

BACKGROUND: Neurofeedback is considered a promising intervention for the treatment of attention-deficit hyperactivity disorder (ADHD). NEWROFEED is a prospective, multicentre, randomized (3:2), reference drug-controlled trial in children with ADHD aged between 7 and 13 years. The main objective of NEWROFEED was to demonstrate the noninferiority of personalized at-home neurofeedback (NF) training versus methylphenidate in the treatment of children with ADHD. METHODS: The NF group (n = 111) underwent eight visits and two treatment phases of 16 to 20 at-home sessions with down-training of the theta/beta ratio (TBR) for children with high TBR and enhancing the sensorimotor rhythm (SMR) for the others. The control group (n = 67) received optimally titrated long-acting methylphenidate. The primary endpoint was the change between baseline and endpoint in the Clinician ADHD-RS-IV total score in the per-protocol population (90 NF/59 controls). TRIAL REGISTRATION: US National Institute of Health, ClinicalTrials.gov #NCT02778360. RESULTS: Our study failed to demonstrate noninferiority of NF versus methylphenidate (mean between-group difference 8.09 90% CI [8.09; 10.56]). However, both treatment groups showed significant pre-post improvements in core ADHD symptoms and in a broader range of problems. Reduction in the Clinician ADHD-RS-IV total score between baseline and final visit (D90) was 26.7% (SMD = 0.89) in the NF and 46.9% (SMD = 2.03) in the control group. NF effects increased whereas those of methylphenidate were stable between intermediate and final visit. CONCLUSIONS: Based on clinicians' reports, the effects of at-home NF were inferior to those of methylphenidate as a stand-alone treatment.

Media use before, during and after COVID-19 lockdown according to parents in a clinically referred sample in child and adolescent psychiatry: Results of an online survey in Switzerland.

BACKGROUND: To investigate the consequences of COVID-19 lockdown on screen media use in children and adolescents with mental health problems, an online survey was conducted on leisure media use before, during and after the lockdown of spring 2020. METHOD: Parents of patients (10-18 yrs) referred to child and adolescent psychiatry participated in an anonymous online survey, approximately six weeks after the first easing of lockdown measures. Parents rated the amount, the content and the psychological impact of their children's media use before, during and after the lockdown. RESULTS: N = 477 parents completed the survey. Patients showed a significant increase in media time during the lockdown (including devices such as mobile, tablet/PC, video game console, TV, and activities such as gaming, social media) and a moderate increase in the negative impact of media use on everyday life. After the lockdown, total media time returned to pre-COVID-19 levels in most patients, but remained slightly higher in males. A worsening of the main psychopathological problem during lockdown was related to elevated media time in children (10-13 yrs), but not in adolescents (14-18 yrs). CONCLUSION: According to parents' retrospective ratings, the increase in screen media time was reversible, and seems to reflect an expected coping strategy during lockdown. However, male patients did not completely return to pre-COVID-19 gaming time, and a small number continued to display excessive gaming.

Impact of the COVID-19 lockdown on screen media use in patients referred for ADHD to child and adolescent psychiatry: an introduction to problematic use of the internet in ADHD and results of a survey.

The COVID-19 outbreak and lockdown have been associated with multiple consequences for mental health, including an excessive and potentially harmful increase in screen media use. The specific consequences for children, adolescents and young adults with ADHD are still unknown. In the first part of this study, a short review of problematic use of the internet (PUI) in ADHD is presented, showing that patients with ADHD are at risk for different aspects of PUI, such as excessive gaming or problematic social media use. In the second part, we report original data of an online survey on screen media use before, during and after the lockdown completed by parents of children and adolescents clinically referred for ADHD. Parents rated children's/adolescents' media-related behavior and media time on a new screening questionnaire for PUI. Each item was rated three times, referring to the observed behavior before, during and 1-2 months after the lockdown. N = 126 parents of patients referred for ADHD aged 10-18 years participated in the study. Total media time increased by 46% during the lockdown and did not completely return to pre-Corona levels afterwards. Patients with difficulties concentrating, high irritability or deterioration of ADHD problems under lockdown spent more time with screen media than those with milder or no such problems. While the effects of the lockdown on screen media use and its negative impact on everyday life appear to be largely reversible, a small proportion of patients with ADHD apparently continue to show increased media use.

Verbal Memory Performance in Depressed Children and Adolescents: Associations with EPA but Not DHA and Depression Severity.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been described as positively associated with cognitive functioning. Current meta-analyses have identified eicosapentaenoic acid (EPA) as potentially more effective than docosahexaenoic acid (DHA). An especially vulnerable subgroup that might benefit from these beneficial effects are depressed youths. In this study, we examined associations between red blood cell (RBC) DHA and EPA levels and depression severity and verbal memory performance in a sample of 107 moderately (n = 63) and severely (n = 44) depressed youths. The findings showed that youths with high RBC EPA levels had steeper learning curves compared to those with moderate or low RBC EPA levels (Pillai's Trace = 0.195, p = 0.027, ηp2 = 0.097). No associations between RBC DHA levels or depression severity and verbal memory performance were observed. Our results further confirm previous findings indicating a more important role of EPA compared to DHA in relation to cognitive functioning. Future research should further investigate the differential role of EPA and DHA concerning cognitive functioning in depressed youths. Evidence supporting beneficial supplementation effects could potentially establish a recommendation for a natural and easily accessible intervention for cognitive improvement or remission.

ADHD: Current Concepts and Treatments in Children and Adolescents.

Attention deficit hyperactivity disorder (ADHD) is among the most frequent disorders within child and adolescent psychiatry, with a prevalence of over 5%. Nosological systems, such as the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and the International Classification of Diseases, editions 10 and 11 (ICD-10/11) continue to define ADHD according to behavioral criteria, based on observation and on informant reports. Despite an overwhelming body of research on ADHD over the last 10 to 20 years, valid neurobiological markers or other objective criteria that may lead to unequivocal diagnostic classification are still lacking. On the contrary, the concept of ADHD seems to have become broader and more heterogeneous. Thus, the diagnosis and treatment of ADHD are still challenging for clinicians, necessitating increased reliance on their expertise and experience. The first part of this review presents an overview of the current definitions of the disorder (DSM-5, ICD-10/11). Furthermore, it discusses more controversial aspects of the construct of ADHD, including the dimensional versus categorical approach, alternative ADHD constructs, and aspects pertaining to epidemiology and prevalence. The second part focuses on comorbidities, on the difficulty of distinguishing between "primary" and "secondary" ADHD for purposes of differential diagnosis, and on clinical diagnostic procedures. In the third and most prominent part, an overview of current neurobiological concepts of ADHD is given, including neuropsychological and neurophysiological researches and summaries of current neuroimaging and genetic studies. Finally, treatment options are reviewed, including a discussion of multimodal, pharmacological, and nonpharmacological interventions and their evidence base.

Omega-3 and its domain-specific effects on cognitive test performance in youths: A meta-analysis.

Omega-3 fatty acids are vital for brain development. The aim of this meta-analysis was to broaden current knowledge of the effects of omega-3 supplementation on cognitive test performance in youths. Randomized controlled trials (RCTs) meeting selection criteria were identified through two independent literature searches on PubMed, Cochrane Library, PsycARTICLES and PsycINFO (last search June 2019). Twenty-nine out of 1126 studies assessing 4247 participants met all selection criteria. A meta-analysis using random-effects model was performed for eight different cognitive domains. This first analysis revealed no main effect of omega-3 fatty acid supplementation on domain-specific cognitive test performance in youths. Subgroup analyses identified beneficial effects of eicosapentaenoic acid (EPA)-rich but not docosahexaenoic acid (DHA)-rich formulations in the domains of long-term memory, working memory and problem solving and a tendency towards beneficial effects in clinical rather than non-clinical populations. Future research should investigate differential effects of EPA and DHA and consider their baseline levels, other nutritional components and interactions with gene variations as potential predictors of response.

Specific Effects of Individualized Cognitive Training in Children with Attention-Deficit/Hyperactivity Disorder (ADHD): The Role of Pre-Training Cognitive Impairment and Individual Training Performance.

Objective: We investigated the impact of the pre-training neuropsychological (NP) impairment and of the training progress on the NP and behavioural outcome after computerized cognitive training (CogT) in children with ADHD. Method: Thirty-one participants underwent individualized CogT (focussing on one or two cognitive domains: working memory, inhibition, attention) over 12 weeks. NP tests and behaviour ratings served as outcome measures. Results: After CogT, significant improvements emerged according to parents' ratings, but only on very few NP test measures. Children with milder/no pre-training NP impairment showed larger improvements on behavioural ratings than more impaired children. A steeper training performance slope was related to better behavioural outcomes. Conclusion: We find partial support for specific effects of CogT, but the assumption that an individually tailored selection of training tasks would be particularly beneficial for children with ADHD with NP deficits was not confirmed. Trial registration number: NCT02358941.

Mixed-Effects Modeling of Neurofeedback Self-Regulation Performance: Moderators for Learning in Children with ADHD.

Introduction: Neurofeedback (NF) has gained increasing popularity as a training method for children and adults with attention deficit hyperactivity disorder (ADHD). However, it is unclear to what extent children learn to regulate their brain activity and in what way NF learning may be affected by subject- and treatment-related factors. Methods: In total, 48 subjects with ADHD (age 8.5-16.5 years; 16 subjects on methylphenidate (MPH)) underwent 15 double training sessions of NF in either a clinical or a school setting. Four mixed-effects models were employed to analyze learning: training within-sessions, across-sessions, with continuous feedback, and with transfer in which performance feedback is delayed. Results: Age and MPH affected the NF performance in all models. Cross-session learning in the feedback condition was mainly moderated by age and MPH, whereas NF learning in the transfer condition was mainly boosted by MPH. Apart from IQ and task types, other subject-related or treatment-related effects were unrelated to NF learning. Conclusion: This first study analyzing moderators of NF learning in ADHD with a mixed-effects modeling approach shows that NF performance is moderated differentially by effects of age and MPH depending on the training task and time window. Future studies may benefit from using this approach to analyze NF learning and NF specificity. The trial name Neurofeedback and Computerized Cognitive Training in Different Settings for Children and Adolescents With ADHD is registered with NCT02358941.

Informant-related effects of neurofeedback and cognitive training in children with ADHD including a waiting control phase: a randomized-controlled trial.

There is controversy regarding the clinical efficacy of neurofeedback (NF) and computerized cognitive training (CogT) as treatments for ADHD. Meta-analyses claim that probably blinded teachers observe smaller effects than parents, because they are less biased. We investigated informant-specific effects by manipulating the involvement of informants, by controlling for waiting time effects, and by adding a blinded outcome measure. Seventy-seven children with ADHD were randomly allocated to slow cortical potential NF or to individualized CogT (of attention, working memory or inhibition). The training was conducted in schools (NF: n = 19, CogT: n = 19) or in outpatient clinics (NF: n = 19, CogT: n = 20). Three assessments were scheduled: baseline, followed by a waiting period, pre-training, and post-training. Multivariate Analyses of Variance were conducted to assess parent- and teacher-rated changes in ADHD symptoms and executive functions (EF), and changes according to standardized classroom observations. Both treatments resulted in significant improvements according to informants, with larger effects for parents (ADHD symptoms: parent η p2  = .32; teacher η p2  = .10), and according to observations (η p2  = .19). The setting had no effect on outcome. Considerable waiting time effects were revealed for ADHD symptom ratings by both informants, for EF ratings only by teachers. Changed classroom behavior was uncorrelated with teacher-rated changes. Overall, the results do not support the notion that teachers are more objective while being as sensitive to change as parents. The three sources seem to contribute differential and mostly unrelated pieces of information to the evaluation of treatments.

The Relations Between Temperament, Character, and Executive Functions in Children With ADHD and Clinical Controls.

OBJECTIVE: The purpose of this study was to investigate the overlap between executive functions and temperament as measured by two questionnaires and to examine characteristic profiles in children with ADHD and clinical controls. METHOD: Parents of 111 clinically referred children, half of whom were diagnosed with ADHD and half with other or no diagnoses, completed the Behavior Rating Inventory of Executive Function (BRIEF) and the Cloninger Junior Temperament and Character Inventory (JTCI). RESULTS: Factor analysis of both instruments resulted in three common factors representing aspects of (1) cognitive regulation, (2) behavioral regulation, and (3) anxious/rigid tendencies. Factor (4) represented strengths and positive resources and loaded on JTCI scales only. Both instruments discriminated significantly between ADHD and non-ADHD children. Conduct disorder/oppositional defiant disorder (CD/ODD) but not ADHD accounted for problems in BRIEF Emotional Control and Self-Monitor and JTCI low Cooperativeness. CONCLUSION: The two instruments only partially overlap and may complement each other.

A Review of the Clinical Utility of Systematic Behavioral Observations in Attention Deficit Hyperactivity Disorder (ADHD).

This review evaluates the clinical utility of tools for systematic behavioral observation in different settings for children and adolescents with ADHD. A comprehensive search yielded 135 relevant results since 1990. Observations from naturalistic settings were grouped into observations of classroom behavior (n = 58) and of social interactions (n = 25). Laboratory observations were subdivided into four contexts: independent play (n = 9), test session (n = 27), parent interaction (n = 11), and peer interaction (n = 5). Clinically relevant aspects of reliability and validity of employed instruments are reviewed. The results confirm the usefulness of systematic observations. However, no procedure can be recommended as a stand-alone diagnostic method. Psychometric properties are often unsatisfactory, which reduces the validity of observational methods, particularly for measuring treatment outcome. Further efforts are needed to improve the specificity of observational methods with regard to the discrimination of comorbidities and other disorders.

Increased decision thresholds enhance information gathering performance in juvenile Obsessive-Compulsive Disorder (OCD).

Patients with obsessive-compulsive disorder (OCD) can be described as cautious and hesitant, manifesting an excessive indecisiveness that hinders efficient decision making. However, excess caution in decision making may also lead to better performance in specific situations where the cost of extended deliberation is small. We compared 16 juvenile OCD patients with 16 matched healthy controls whilst they performed a sequential information gathering task under different external cost conditions. We found that patients with OCD outperformed healthy controls, winning significantly more points. The groups also differed in the number of draws required prior to committing to a decision, but not in decision accuracy. A novel Bayesian computational model revealed that subjective sampling costs arose as a non-linear function of sampling, closely resembling an escalating urgency signal. Group difference in performance was best explained by a later emergence of these subjective costs in the OCD group, also evident in an increased decision threshold. Our findings present a novel computational model and suggest that enhanced information gathering in OCD can be accounted for by a higher decision threshold arising out of an altered perception of costs that, in some specific contexts, may be advantageous.

German Validation of the Conners 3® Rating Scales for Parents, Teachers, and Children.

Objective: Attention-deficit/hyperactivity disorder (ADHD) rating scales such as the Conners' Rating Scales (CRS) are valuable adjuncts for diagnosis, since they offer parent, teacher, and self-ratings of children susceptible for ADHD. Even though the scales are widely used internationally, cross-cultural comparability has rarely been verified, and culture and language invariance have only been presumed. The Conners 3(®) rating scales are the updated version of the CRS, though hardly any studies report the psychometric properties apart from the results published in the test edition itself. To our knowledge there are no studies on the various adaptations of the Conners 3(®) in other languages. Method: The German translations of the Conners 3(®) were completed by 745 children, 953 parents, and 741 teachers (children's age range: 6­18 years, mean: 11.74 years of age). Exploratory and confirmatory factor analyses on content scale items were conducted to obtain the factor structure for the German version and to replicate the factor structure of the original American models. Cronbach's α was calculated to establish internal consistency. Results: The exploratory analyses for the German model resulted in factor structures globally different from the American model, though confirmatory analyses revealed very good model fi ts with highly satisfying Cronbach's αs. We were able to provide empirical evidence for the subscale Inattention which had only hypothetically been derived by Conners (2008). Conclusions: Even though the exploratory analyses resulted in different factor structures, the confirmatory analyses have such excellent psychometric properties that use of the German adaptation of the Conners 3(®) is justifi ed in international multicenter studies.

Are treatment effects of neurofeedback training in children with ADHD related to the successful regulation of brain activity? A review on the learning of regulation of brain activity and a contribution to the discussion on specificity.

While issues of efficacy and specificity are crucial for the future of neurofeedback training, there may be alternative designs and control analyses to circumvent the methodological and ethical problems associated with double-blind placebo studies. Surprisingly, most NF studies do not report the most immediate result of their NF training, i.e., whether or not children with ADHD gain control over their brain activity during the training sessions. For the investigation of specificity, however, it seems essential to analyze the learning and adaptation processes that take place in the course of the training and to relate improvements in self-regulated brain activity across training sessions to behavioral, neuropsychological and electrophysiological outcomes. To this aim, a review of studies on neurofeedback training with ADHD patients which include the analysis of learning across training sessions or relate training performance to outcome is presented. Methods on how to evaluate and quantify learning of EEG regulation over time are discussed. "Non-learning" has been reported in a small number of ADHD-studies, but has not been a focus of general methodological discussion so far. For this reason, selected results from the brain-computer interface (BCI) research on the so-called "brain-computer illiteracy", the inability to gain control over one's brain activity, are also included. It is concluded that in the discussion on specificity, more attention should be devoted to the analysis of EEG regulation performance in the course of the training and its impact on clinical outcome. It is necessary to improve the knowledge on characteristic cross-session and within-session learning trajectories in ADHD and to provide the best conditions for learning.

The neurobiological link between OCD and ADHD.

Obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) are two of the most common neuropsychiatric diseases in paediatric populations. The high comorbidity of ADHD and OCD with each other, especially of ADHD in paediatric OCD, is well described. OCD and ADHD often follow a chronic course with persistent rates of at least 40-50 %. Family studies showed high heritability in ADHD and OCD, and some genetic findings showed similar variants for both disorders of the same pathogenetic mechanisms, whereas other genetic findings may differentiate between ADHD and OCD. Neuropsychological and neuroimaging studies suggest that partly similar executive functions are affected in both disorders. The deficits in the corresponding brain networks may be responsible for the perseverative, compulsive symptoms in OCD but also for the disinhibited and impulsive symptoms characterizing ADHD. This article reviews the current literature of neuroimaging, neurochemical circuitry, neuropsychological and genetic findings considering similarities as well as differences between OCD and ADHD.