Attention Deficit Hyperactivity Disorder (ADHD), an intellectual impairment, generally characterised by inattentiveness and impulsivity has become prevalent in South African schools. ADHD learners require support from within the classroom to accommodate their academic and behavioural needs. A quantitative research was undertaken to determine the impact of an educator's knowledge of ADHD on teaching support strategies. An educator's ADHD knowledge is based on their understanding of the diagnosis, causes, symptoms and management of ADHD as well as the effect that ADHD has on a learner's classroom skills. Data was obtained from responses to questionnaires from randomly selected respondents within randomly selected government secondary schools in the Umlazi District of Kwa-Zulu Natal. The data was descriptively analysed to conclude that the level of ADHD knowledge possessed by educators impact on the appropriateness of their teaching strategies. There is a need to impart knowledge regarding learning barriers to educators, to ensure the efficacy of teaching strategies. / Inclusive Education / M. Ed. (Inclusive Education)

The purpose of the study was to examine the relationship between sleep patterns, motor proficiency and commonly co-occurring neurodevelopmental disorders in children, attitude to physical activity, mental health, and age. The study also looked at differences in sleep efficiency, as well as, perceived adequacy in physical activity between typically developing children and children with low motor proficiency. The sample consisted of 127 participants, 6-12 years old living in Perth, Western Australia. 51% participants were considered typically developing and 49% to have low motor proficiency. Motor proficiency, indications of Attention-Deficit/Hyperactivity Disorder, Autism Spectrum Disorder and anxiety/depression, adequacy in, or predilection for physical activity did not show a relationship to sleep efficiency. Significant differences between groups in sleep efficiency or adequacy in physical activity were not found. No interaction effect of neurodevelopmental disorders were identified. Sleep in children with movement impairments caused by neurodevelopmental disorders is an area where continued studies are of great importance. Although no relationship was identified in the current study, previous research has suggested sleep may play an important role for development and optimal everyday functioning. A better understanding of physical and psychological consequences and possible contributing factors of low motor proficiency in childhood is important as the risk of long-term dysfunction in emotional, cognitive and physical areas may be reduced in an optimal environment.

Succédant à une théorisation centrée sur le rôle des déficits des fonctions exécutives, les modèles contemporains du trouble déficit de l'attention / hyperactivité (TDAH) mettent en avant l’hétérogénéité d’une catégorie diagnostique impliquant des déficits neuropsychologiques, voies cérébrales et mécanismes étiopathogéniques multiples. En dépit de cette évolution, la majorité des études d'imagerie cérébrale des corrélats structurels du trouble menées à ce jour ont été conduites au niveau de la catégorie diagnostique, sans spécification supplémentaire. Cette approche comparant en moyenne un groupe de patients avec TDAH à un groupe de sujets sains a donné des résultats très variables d'une étude à l'autre, la comparaison inter-étude étant toutefois rendue difficile par la présence de facteurs confondants, tels que des différences en terme de régions d’intérêt examinées, de comorbidités acceptées chez les patients, de pourcentages de sujets masculins et féminins, de fenêtre d’âge sélectionnée, de méthodologie d'analyse ou encore de pourcentage de patients traités par méthylphénidate. Dans ce doctorat, nous nous sommes appuyés sur la morphométrie voxel-à-voxel pour isoler l’influence sur les volumes de matière grise de deux facteurs d’hétérogénéité intra-catégorielle dans le TDAH : le genre d’une part, et un polymorphisme génétique (Val158Met du gène Catéchol-O-méthyltransferase (COMT)) d’autre part ; ces deux facteurs présentant l’intérêt de moduler le risque associé de développer un trouble de type externalisé. Nous avons également comparé les volumes de matière grise d’enfants avec TDAH ayant reçu un traitement par méthylphénidate, de patients n'ayant jamais été exposé à la médication, et de sujet sains. Ces recherches expérimentales ont été inscrites dans une discussion plus générale de l’hétérogénéité des résultats de la littérature structurelle consacrée au TDAH et des sources neuropsychologiques de cette hétérogénéité. Dans notre étude des effets du genre sur les volumes de matière grise dans le TDAH, nous reportons pour la première fois une interaction entre genre et diagnostic, avec des corrélats structurels du trouble différents chez les garçons et les filles avec TDAH dans des régions de la ligne médiane du cerveau, impliquées à la fois dans la régulation émotionnelle et dans le fonctionnement du mode de réseau par défaut. Nous suggérons que ces différences structurelles pourraient contribuer aux différences de risque associé pour les troubles internalisés et externalisés présentées par les garçons et filles avec TDAH. Dans notre étude explorant l'influence du polymorphisme Val158Met sur les volumes de matière grise, nous mettons en évidence une modulation génétique des corrélats structurels du trouble : les sujets homozygotes pour l'allèle Val158, identifiés dans la littérature comme à risque pour le développement d'un trouble des conduites, présentent des volumes de matière grise supérieurs dans le noyau caudé comparativement aux sujets sains, tandis que les patients avec TDAH porteurs d'un allèle Met158 présentent des volumes de matière grise plus faibles dans le cortex préfrontal inférieur droit, une région cruciale pour les processus de contrôle attentionnel. Enfin, dans notre étude des corrélats structurels de l'exposition au méthylphénidate, nous reportons un effet potentiellement normalisateur du traitement sur les volumes de matière grise de l'insula et du pole temporal, des volumes de matière grise plus faibles chez les patients traités comparativement aux sujets sains dans le gyrus frontal moyen et dans le gyrus précentral, et une association entre volume de matière grise dans le nucleus accumbens gauche et durée d'exposition au méthylphénidate chez les sujets traités. (...) / Previous models of Attention Deficit / Hyperactivity Disorder (ADHD) such as Barkley’s or Brown’s conceptualized ADHD as essentially a developmental impairment of executive function. Against this view, it is now recognized that ADHD is a heterogeneous disorder, involving multiple deficits and multiple neuronal pathways. Despite this current theoretical framework, most structural brain imaging studies in ADHD have compared groups of children with ADHD with typically developing children, without trying to identify subgroups within the diagnostic category. This approach has yielded heterogeneous findings, possibly due to inter-studies variations in the type and number of comorbidities, the percentage of medicated participants included, the number of girls included, and/or methodological and statistical differences. Patients participating in these studies were also often exposed to methylphenidate, and potential medication effects on grey matter volumes are still unclear in certain brain regions such as the frontal lobe, despite a therapeutic action involving the preferential activation of catecholamine neurotransmission within the prefrontal cortex. In this thesis, we used voxel-based morphometry to study the influence of two important risk factors for the development of comorbid conditions in ADHD. The first of these two factors was gender, and the second a genetic polymorphism of the Catechol-O-methyltransferase gene known to put children with ADHD at risk for developing a conduct disorder (Val158Met). We also compared grey matter volumes in children with ADHD exposed to methylphenidate, never-medicated children with ADHD and typically developing children. These experimental studies were part of a more general discussion of ADHD neuropsychological and neurobiological heterogeneity. In our study exploring the influence of gender on the structural correlates of ADHD, we report for the first time a gender-by-diagnosis interaction, with grey matter volume differences in boys and girls with ADHD in midline cortical structures, involved in emotional regulation and part of the default mode network. We propose that these differences may contribute to explain why girls with ADHD more often develop inattentive and internalizing symptoms, whereas externalizing symptoms are predominant in boys with ADHD. In our study investigating the effects of Val158Met in ADHD, we report the first evidence of a COMT-related genetic modulation of ADHD-related grey matter volume alterations. Indeed, children with ADHD at higher risk for developing a conduct disorder (children homozygotes for the Val158 allele) presented increased grey matter volumes in the caudate nucleus when compared with typically developing children, whereas children carrying a Met158 allele presented with decreased grey matter volumes in the right inferior frontal cortex, a region known for its key role in attention. Finally, we measured grey matter volumes in medicated children with ADHD, never-medicated children with ADHD and typically developing children using both whole-brain voxel-based morphometry and automated tracing procedures in chosen regions of interest. We document potential methylphenidate-related grey matter volume normalization and deviation in previously unexplored frontal and temporal regions, and report a positive association between treatment history and grey matter volume in the nucleus accumbens, a key region for reward processing. Our first two experimental studies therefore contribute to a better understanding of the influence of important sources of within-category heterogeneity, while the third helps clarifying the potential confounding effect of medication exposure in previous structural brain imaging studies in ADHD.

À ce jour, plusieurs études se sont penchées sur l’influence des comportements problématiques des enfants présentant un trouble déficitaire de l'attention avec ou sans hyperactivité (TDAH) sur les pratiques parentales (Chronis-Tuscano et al., 2008), mais peu de recherches se sont intéressées à la relation entre ce que pensent les parents et la façon dont ils se comportent avec leur enfant (Rudy & Grusec, 2006). L’objectif principal de cette thèse est d’étudier la relation entre les cognitions sociales des parents, les pratiques parentales et les caractéristiques comportementales de l’enfant présentant un TDAH. Une première étude examine la relation entre les cognitions sociales des parents (attributions causales, sentiment d’auto-efficacité parental (SAEP)), les caractéristiques comportementales de l’enfant (sous-type TDAH, symptômes concomitants) en lien avec les pratiques parentales utilisées. Cent dix familles dont l’enfant a un TDAH ont participé à l’étude. Les résultats indiquent que plus les parents ont un SAEP élevé, plus ils rapportent employer une discipline appropriée, une discipline verbale positive, des félicitations/récompenses et moins ils rapportent utiliser une discipline sévère/inconstante ou la punition physique. Les résultats montrent également que l’attribution des comportements de désobéissance de l’enfant soit à l’effort important du parent, soit au manque d’effort de l’enfant joue un rôle prédicteur en regard respectivement de l’utilisation d’une discipline verbale positive ou de l’utilisation d’une discipline sévère et inconstante par le parent. Par ailleurs, le fait de percevoir des symptômes d’opposition chez l’enfant TDAH prédit l’utilisation d’une discipline appropriée et d’une discipline verbale positive. Enfin, la présence de symptômes concomitants au TDAH prédit l’utilisation d’une discipline sévère et inconstante. L’objectif de la seconde étude est d’examiner le rôle des cognitions sociales des parents d’enfant ayant un TDAH en lien avec les pratiques parentales utilisées après leur participation à deux types d’intervention (programme d’entraînement aux habiletés parentales (PEHP) ou soutien téléphonique (ST)) comparativement à un groupe contrôle (GC). Les résultats suggèrent que dans certains cas, le SAEP ou les attributions causales prédisent différemment les pratiques parentales selon que les parents ont ou non participé à une intervention, mais il est prématuré de conclure que les cognitions sociales des parents d’enfant TDAH sont des modérateurs du changement des pratiques parentales. Les implications méthodologiques, conceptuelles et cliniques de ces deux études sont discutées. / Studies have confirmed that behavior of children with attention-deficit/hyperactivity disorder (ADHD) affects parents’ parenting practices (Chronis-Tuscano et al., 2008). However, only few studies have investigated the association between parental social cognition and parenting practices in parents of children with ADHD (Rudy & Grusec, 2006). The principal purpose of this thesis was to examine the association between parental social cognitions, parental practices and the behavioural characteristics of their child diagnosed with ADHD. The purpose of the first study was to examine the association between parental social cognitions (parental causal attributions, parental self-efficacy), behavioural characteristics of their child (ADHD subtypes, comorbidity symptoms) and parental practices. Multiple regressions indicate that parental self-efficacy is associated with more use of appropriate discipline, praise and incentives, positive verbal discipline, and less use of harsh and inconsistent discipline and physical punishment. Results also show that parental causal attributions for the child’s misbehaviour to their own efforts are a predictor of positive verbal discipline whereas parents’ causal attributions for the child’s misbehaviour to the child’s lack of efforts are a predictor of harsh and inconsistent discipline. Parents’ perception of their child’s oppositional symptom is a predictor of appropriate discipline and positive verbal discipline. Finally, the presence of comorbidity symptoms in ADHD children is a predictor of harsh and inconsistent discipline. The purpose of the second study was to examine the association between cognitions (self-efficacy, causal attributions) of parents of ADHD children about their child’s behavior and their parental practices following an intervention (parent training program (PTP), support phone call (SPC)) in comparison with a control group (CG). Multiple regressions indicated that in some instances parental self-efficacy and causal attributions were predictors of parenting practices after the intervention. However it would be premature to conclude to the moderating role of social cognitions with regard to parenting practices following an intervention. Clinical implications of these results are explored in the discussion.

Therapeutic horseback riding is one of the most popular and the most used form of animal based therapy. The term "therapeutic horseback riding" itself is very broad and it consists of four basic branches. The most used, yet least described, is the branch that has been called "pedagogical-psychological horseback riding therapy" since 2011. This branch is further divided into two sub-branches, Equine assisted psychotherapy and Horse-based activities. These two sub-branches overlap each other and are usually conducted together. With school-age children they are mostly used in cases of behavioral disorders and ADHD. The goal of the thesis is to evaluate the effectiveness of the methods with children diagnosed as such. The research was realized in "Stredisko hyporehabilitace Pirueta" which operates within the Mental Hospital in Havlickuv Brod. The method of the research was observation of five subjects within the one complete therapy unit. At the beginning and at the end of the unit the tutors of the subjects were given observational scale, which served as supplementary technique for diagnostics. Data obtained from own observation and the data gained from observational scaled matched each other approximately in 90%. During the therapy unit all the subjects improved in areas of self-confidence, self-...

The issue of psychiatric co-morbidity is a serious public health problem occurring more and more frequently in the treatment of addiction and bringing with it various complications and often premature termination of treatment. The scoring system with a fixed set regime is still being used as the main instrument for treatment of addicted clients on the most specialized departments of psychiatric hospitals, although the effectiveness of the scoring system has not yet been clinically verified. The aim of this pilot study is to demonstrate and verify of the individual cases of clients with different categories of dual diagnosis, how they perceive the balance of the sanctions and rewards and fair setting in the context of the scoring system. Other goals are to find out and verify what is the influence of the scoring system on the motivation to change the behavior and success of treatment, what weaknesses clients with dual diagnosis perceive in this system and how they represent the treatment system, which would make them more fit and motivated to change behavior. Further, this study seeks to establish whether difficulties and obstacles on the way to stand up and go through the scoring system are different for individual dual diagnoses. A qualitative approach is used in the research part of the thesis....

Background: Given the incomplete benefits of the pharmacological therapy for ADHD and its over-prescription in children over the last decades, there is an explicit need for alternative treatments. Mindfulness-based Interventions (MBIs) are a family of emergent self-regulation practices including meditation, yoga and body-awareness exercises, found to be an effective therapy for ADHD. Due to poor methodological design and significant risk of bias across studies, mindfulness approach remains an investigational treatment. Aim: This systematic review sought to identify and critically appraise the evidence on the functioning outcomes of MBIs in children and youth with ADHD. Method: The literature search was conducted in 7 databases for psychology and social sciences to identify controlled trials – randomized- and non-randomized, evaluating MBIs published in peer-reviewed journal in English between 2000-2019. Only studies focusing on children and youth aged 7-18 years with documented ADHD symptoms were considered for inclusion. Results: Six controlled trials were included and analysed. Meditation, breathing techniques, self-awareness and yoga exercises were the most common activities implemented across the 6 studies. Significant reduction of inattention and hyperactivity/impulsivity symptoms; and improvements of sustained attention, working memory and emotional regulation were reported across studies, with small to large effect size. Conclusion: Despite the limitations, MBIs do prove to be an effective complementary treatment for reduction of the core ADHD symptoms and improvement of executive functioning (EF). Further research is needed to elucidate how these interventions improve social functioning and participation of children and youth with ADHD, which would enable a wider implementation of these practices at the community level.

Succédant à une théorisation centrée sur le rôle des déficits des fonctions exécutives, les modèles contemporains du trouble déficit de l'attention / hyperactivité (TDAH) mettent en avant l’hétérogénéité d’une catégorie diagnostique impliquant des déficits neuropsychologiques, voies cérébrales et mécanismes étiopathogéniques multiples. En dépit de cette évolution, la majorité des études d'imagerie cérébrale des corrélats structurels du trouble menées à ce jour ont été conduites au niveau de la catégorie diagnostique, sans spécification supplémentaire. Cette approche comparant en moyenne un groupe de patients avec TDAH à un groupe de sujets sains a donné des résultats très variables d'une étude à l'autre, la comparaison inter-étude étant toutefois rendue difficile par la présence de facteurs confondants, tels que des différences en terme de régions d’intérêt examinées, de comorbidités acceptées chez les patients, de pourcentages de sujets masculins et féminins, de fenêtre d’âge sélectionnée, de méthodologie d'analyse ou encore de pourcentage de patients traités par méthylphénidate. Dans ce doctorat, nous nous sommes appuyés sur la morphométrie voxel-à-voxel pour isoler l’influence sur les volumes de matière grise de deux facteurs d’hétérogénéité intra-catégorielle dans le TDAH : le genre d’une part, et un polymorphisme génétique (Val158Met du gène Catéchol-O-méthyltransferase (COMT)) d’autre part ; ces deux facteurs présentant l’intérêt de moduler le risque associé de développer un trouble de type externalisé. Nous avons également comparé les volumes de matière grise d’enfants avec TDAH ayant reçu un traitement par méthylphénidate, de patients n'ayant jamais été exposé à la médication, et de sujet sains. Ces recherches expérimentales ont été inscrites dans une discussion plus générale de l’hétérogénéité des résultats de la littérature structurelle consacrée au TDAH et des sources neuropsychologiques de cette hétérogénéité. Dans notre étude des effets du genre sur les volumes de matière grise dans le TDAH, nous reportons pour la première fois une interaction entre genre et diagnostic, avec des corrélats structurels du trouble différents chez les garçons et les filles avec TDAH dans des régions de la ligne médiane du cerveau, impliquées à la fois dans la régulation émotionnelle et dans le fonctionnement du mode de réseau par défaut. Nous suggérons que ces différences structurelles pourraient contribuer aux différences de risque associé pour les troubles internalisés et externalisés présentées par les garçons et filles avec TDAH. Dans notre étude explorant l'influence du polymorphisme Val158Met sur les volumes de matière grise, nous mettons en évidence une modulation génétique des corrélats structurels du trouble : les sujets homozygotes pour l'allèle Val158, identifiés dans la littérature comme à risque pour le développement d'un trouble des conduites, présentent des volumes de matière grise supérieurs dans le noyau caudé comparativement aux sujets sains, tandis que les patients avec TDAH porteurs d'un allèle Met158 présentent des volumes de matière grise plus faibles dans le cortex préfrontal inférieur droit, une région cruciale pour les processus de contrôle attentionnel. Enfin, dans notre étude des corrélats structurels de l'exposition au méthylphénidate, nous reportons un effet potentiellement normalisateur du traitement sur les volumes de matière grise de l'insula et du pole temporal, des volumes de matière grise plus faibles chez les patients traités comparativement aux sujets sains dans le gyrus frontal moyen et dans le gyrus précentral, et une association entre volume de matière grise dans le nucleus accumbens gauche et durée d'exposition au méthylphénidate chez les sujets traités. (...) / Previous models of Attention Deficit / Hyperactivity Disorder (ADHD) such as Barkley’s or Brown’s conceptualized ADHD as essentially a developmental impairment of executive function. Against this view, it is now recognized that ADHD is a heterogeneous disorder, involving multiple deficits and multiple neuronal pathways. Despite this current theoretical framework, most structural brain imaging studies in ADHD have compared groups of children with ADHD with typically developing children, without trying to identify subgroups within the diagnostic category. This approach has yielded heterogeneous findings, possibly due to inter-studies variations in the type and number of comorbidities, the percentage of medicated participants included, the number of girls included, and/or methodological and statistical differences. Patients participating in these studies were also often exposed to methylphenidate, and potential medication effects on grey matter volumes are still unclear in certain brain regions such as the frontal lobe, despite a therapeutic action involving the preferential activation of catecholamine neurotransmission within the prefrontal cortex. In this thesis, we used voxel-based morphometry to study the influence of two important risk factors for the development of comorbid conditions in ADHD. The first of these two factors was gender, and the second a genetic polymorphism of the Catechol-O-methyltransferase gene known to put children with ADHD at risk for developing a conduct disorder (Val158Met). We also compared grey matter volumes in children with ADHD exposed to methylphenidate, never-medicated children with ADHD and typically developing children. These experimental studies were part of a more general discussion of ADHD neuropsychological and neurobiological heterogeneity. In our study exploring the influence of gender on the structural correlates of ADHD, we report for the first time a gender-by-diagnosis interaction, with grey matter volume differences in boys and girls with ADHD in midline cortical structures, involved in emotional regulation and part of the default mode network. We propose that these differences may contribute to explain why girls with ADHD more often develop inattentive and internalizing symptoms, whereas externalizing symptoms are predominant in boys with ADHD. In our study investigating the effects of Val158Met in ADHD, we report the first evidence of a COMT-related genetic modulation of ADHD-related grey matter volume alterations. Indeed, children with ADHD at higher risk for developing a conduct disorder (children homozygotes for the Val158 allele) presented increased grey matter volumes in the caudate nucleus when compared with typically developing children, whereas children carrying a Met158 allele presented with decreased grey matter volumes in the right inferior frontal cortex, a region known for its key role in attention. Finally, we measured grey matter volumes in medicated children with ADHD, never-medicated children with ADHD and typically developing children using both whole-brain voxel-based morphometry and automated tracing procedures in chosen regions of interest. We document potential methylphenidate-related grey matter volume normalization and deviation in previously unexplored frontal and temporal regions, and report a positive association between treatment history and grey matter volume in the nucleus accumbens, a key region for reward processing. Our first two experimental studies therefore contribute to a better understanding of the influence of important sources of within-category heterogeneity, while the third helps clarifying the potential confounding effect of medication exposure in previous structural brain imaging studies in ADHD.

O desenvolvimento de novas tecnologias vem contribuindo para um conhecimento mais aprofundado da fisiopatologia dos transtornos psiquiátricos, mas os resultados ainda são controversos e não parecem ser específicos para cada diagnóstico. As altas taxas de comorbidade também questionam as características principais de um diagnóstico específico. Em 2009, o Instituto Nacional de Saúde Mental dos EUA iniciou um projeto chamado Research Domain Criteria (RDoC) com o objetivo de desenvolver novas classificações para a pesquisa baseadas em dimensões de comportamentos observáveis associadas a medidas neurobiológicas. Para o estudo da fisiopatologia da comorbidade entre duas doenças mentais, esta proposta sugere que se execute o estudo de sintomas compartilhados e não partir de dois grupos diagnósticos distintos. Na psiquiatria infantil, as altas taxas de comorbidade entre o transtorno do humor bipolar (THB) e o transtorno de déficit de atenção e hiperatividade (TDAH) são um tema controverso. O prejuízo na atenção é um forte candidato para um estudo com a metodologia proposta pelo RDoC visto que os poucos estudos que avaliaram concomitantemente a atenção em jovens com THB e TDAH apresentaram resultados contraditórios. Um dos testes mais utilizados para o estudo da atenção em THB e TDAH é o Continuous Performance Test (CPT). Nossos objetivos foram: 1.Verificar qual é o melhor agrupamento dos sujeitos através dos resultados do Conner\'s Continuous Performance Test (CPT II) independentemente do grupo de origem (THB, TDAH, THB+TDAH, controles); 2. Construir um classificador baseado nos resultados do CPT II; 3com THB+TDAH e 18 controles com idades entre 12 e 17 anos. A melhor divisão dos sujeitos, baseada nos resultados do CPT II, foi em dois novos subgrupos. Grupo A com 35 sujeitos composto de: 30% THB, 52,2% TDAH, 51,5% THB+TDAH, e 16,7% controles. Grupo B com 49 sujeitos: 70% THB, 47,8% TDAH, 48,5% THB+TDAH, e 83,3% controles. O grupo A comparado com o B apresentou um prejuízo funcional maior evidenciado por médias significativamente mais altas no CPT II, com uma diferença significativa em oito das 12 variáveis do CPT II: omissão (p=0,0003), comissão (p=0,00000002), erro padrão (EP) do tempo de reação (TR) (p=1,7x10-20), variabilidade do EP (p=4,3x10-22), detectabilidade (p=0,000008), perseveração (p=0,0000001), TR por intervalo interestímulo (IIE) (p=4,7x10-10) e TR(EP)IIE (p= 1,5x10 -13). Foi possível construir um classificador baseado nas doze variáveis do CPT II, sendo sua acurácia de 98,8% em relação a nossa amostra e 95,2% em relação à validação cruzada confirmando a consistência desses novos grupos. As principais variáveis do CPT II usadas na função discriminante desses novos agrupamentos foram: variabilidade do erro padrão, erro padrão de TR e erro padrão de TR por intervalo interestímulo. Não houve diferença estatística em nenhuma das variáveis do CPT II quando realizamos a comparação tradicional entre THB, TDAH, THB+TDAH, e controles; e a acurácia do classificador para esses grupos foi mais baixa, de 40,5% na nossa amostra e 23,8% na validação cruzada. Discussão: Esses resultados evidenciam a heterogeneidade encontrada nas respostas do CPT II pelos grupos THB, TDAH, THB+TDAH, e controles. As três medidas que mais influenciaram a diferenciação entre os novos agrupamentos A e B foram as que medem a variação no tempo de resposta, que é um dos prejuízos mais replicados no TDAH e também está associada com THB. Essa variabilidade de resposta aumentada é sugerida como um marcador endofenotípico inespecífico de psicopatologia. Conclusão: Nossos achados refletem a heterogeneidade encontrada em pacientes classificados através de categorias diagnósticas vigentes e sugerem que a abordagem da metodologia do RDoC pode ser de grande valia para a melhor compreensão dos transtornos psiquiátricos que acometem crianças e adolescentes. Essa metodologia pode identificar subgrupos com diferenças relevantes do ponto de visto neurobiológico contribuindo para a melhor compreensão da fisiopatologia dos transtornos e promovendo caminhos nos quais a pesquisa pode trazer benefícios para decisões clínicas / The better understanding of psychiatric disorders\' pathophysiology is undeniable. Yet, the results are still replete of controversy and are not diagnostic specific. Categorical approach analysis implicitly involves the notion of a unitary entity, not taking into account the acknowledged heterogeneity present in clinical diagnoses. High comorbidity rates also raises questions about the core features of a specific diagnosis. For this purpose, the National Institute of Mental Health has initiated the Research Domain Criteria (RDoC) project. Instead of using disorders categories as the basis for grouping individuals, RDoC suggests to find relevant dimensions that can cut across traditional disorders. The starting point suggested to study comorbid disorders should be shared symptoms and behaviors, instead of two distinct diagnostic groups. One of the strongest controversies in child psychiatry is the high comorbidity rate between bipolar disorder (BD) and attention-deficit/hyperactivity disorder (ADHD). Distractibility, one of the most common symptoms in BD and ADHD could be a good candidate for an RDoC unit of analysis. Our aim was first to study the patterns of attention based on the Conners\' Continuous Performance Test (CPTII) results in youth with BD, ADHD, BD+ADHD and controls; followed by developing a classifier to compare the classification accuracy of this new formed groups and the original diagnostic ones. Results: 18 healthy controls, 23 patients with ADHD, 33 BD+ADHD and 10 BD were assessed. Using cluster analysis, the entire sample was best clustered in two new groups, A and B, based on the twelve CPT II variables performance, independently of the original diagnoses. 35 subjects in group A: 30% BD, 52.2% ADHD, 51.5% BD+ADHD and 16.7% controls. 49 individuals in group B: 70% BD, 47.8% ADHD, 48.5% BD+ADHD and 83.3% controls. Group A presented a greater impairment exhibited by higher means in all CPTII variables, SNAP-IV means, and lower CGAS means. When we compared the CPT II variables performance between the new clustered groups A and B we found eight out of the twelve CPT II measures that were statistically significant: omission (p=0.0003), commission (p=0.00000002), standard error (SE) of hit reaction time (RT) (p=1.7x10-20), variability of SE (p=4.3x10 -22), detectability (p=0.000008), perseveration (p=0.0000001), hit RT by interstimulus interval (ISI) (p=4.7x10 - 10) and hit RT SE ISI. We found high cross-validated classification accuracy for A and B groups: 95.2%. The stronger CPT II variables in the discriminative pattern were: variability of standard error ranking first, followed by hit RT SE, hit RT SE ISI. There were no statistically significant differences in any of the CPT II measures when comparing the four original groups (BD, ADHD, BD+ADHD, controls). The cross-validated classification accuracy based on the CPT II measures performance in order to classify subjects in the original four groups was much lower (23.8%). Discussion: These results highlight the heterogeneity of CPT II responses among each of the four original groups: BD, ADHD, BD+ADHD and controls. The three variables that most influenced the new clustered groups were the ones that measure and adolescents may share this attentional trait marker. Conclusion: In summary, our findings highlighted the heterogeneity of patients clustered by categorical diagnostic classification. In addition, our classificatory exercise supports the concept behind new approaches like the RDoC framework for child and adolescent psychiatry. It can define meaningful clinical subgroups for the purpose of pathophysiological studies and treatment selection, and provide a pathway by which research findings can be translated into changes in clinical decision making

Abstract Not Available.