Le trouble déficitaire de l'attention/hyperactivité (TDA/H) est une problématique qui touche un nombre important de jeunes Québécois. Un lien entre le TDA/H, plus particulièrement la composante inattention, et l’apparition de difficultés scolaires a été démontré à maintes reprises. Quelques études suggèrent que la pratique d'activités sportives pourrait influencer le lien entre l'inattention et les difficultés scolaires et augmenter ainsi la probabilité de perséverer dans les études et, conséquemment, d’obtenir un diplôme scolaire. La présente étude vise à examiner le lien entre l’inattention durant l’enfance et l’obtention du diplôme d’études secondaires, puis à vérifier si la pratique d'activités sportives durant l’adolescence influence ce lien. À cette fin, 1043 jeunes ont été suivis de 6 à 23 ans. Une analyse de régression logistique binaire de type hiérarchique a été utilisée pour tester les hypothèses proposées. D’une part, et tel que prévu, une forte association négative entre l’inattention et la diplomation est observée. Cette association demeure satistiquement significative après contrôle de différentes variables (hyperactivité, symptômes intériorisés, Q.I. et l’adversité familiale). La relation inattention-diplomation n’est toutefois pas modérée par la pratique d’activités sportives. Cette étude souligne l’importance de mettre en place des mesures efficaces pour permettre aux jeunes souffrant d’inattention d’avoir de meilleures chances de diplômer. / Attention deficit/hyperactivity disorder (ADHD) is a mental health issue that many youths have to deal with. It is of great concern as many authors report a link between ADHD and academic problems. It has been shown that inattention levels contribute more to academic problems than hyperactivity levels per se. On the other hand, the results of few studies suggest that sport activities could influence the link between inattention and academic problems. The aims of this study was to investigate the link between inattention at the end of childhood and high school graduation and to examine the hypothesis that sport activities during adolescence could moderate that relation. To this end, 1043 youths were followed from 6 to 23 years old, as part of the Montreal longitudinal and experimental stud. Binary logistic regression analysis was conduct to test the proposed hypotheses. The results indicate a strong association between inattention and high school graduation. This relation remained statistically significant after controlling for associated problems (hyperactivity, internalized symptoms), I.Q., and familial adversity. The relation inattention-high school graduation was not moderated by sport activities, however. This study emphasizes the importance of implementing measures that could help youths with inattention problems achieving academic success.

Background: Children born very preterm are at an elevated risk of behavioural adjustment problems, particularly Attention-Deficit/Hyperactivity Disorder (ADHD) or inattention/hyperactivity difficulties. Importantly, these risks remain even after controlling for the effects of social risk factors correlated with very preterm birth. Behavioural outcomes in follow-up studies of children born very preterm are typically assessed using parent reports only. However, the extent to which behavioural problems are evident across multiple contexts (i.e., parent or teacher report) is not well known. Furthermore, the neonatal neuropathology underlying these behavioural difficulties in this population remains poorly understood. Aims: Three research studies are undertaken primarily to examine: (1) the degree of agreement between parent and teacher reports of child behaviour adjustment, and the extent of situational (parent- or teacher-identified) and pervasive (parent- and teacher-identified) inattention/hyperactivity problems at ages 4, 6, and 9 years among children born very preterm and full-term; (2) to cross-validate the classification of children with situational and pervasive inattention/hyperactivity problems across the ages of 4 to 9, for a clinical diagnosis of ADHD at age 9 years; (3) to document risk of persistent ADHD symptoms between ages 4 and 9 years in children born very preterm, and to examine associations between qualitative measures of neonatal cerebral white matter injury/abnormality and quantitative volumetric measures of cerebral structural development, identified using magnetic resonance imaging (MRI) at term equivalent age, and children’s later risks of persistent symptoms. Persistent ADHD symptoms were defined as behavioural inattention/hyperactivity problems shown at ages 4, 6, and 9, along with meeting the criteria for an ADHD clinical diagnosis at age 9 years. Methods: As part of a prospective longitudinal study, a regional cohort of 110 very preterm (≤ 33 weeks of gestation) and 113 full-term children born between 1998 and 2000 were studied from birth to age 9 years. At term equivalent age, all children born very preterm and 10 children born full-term underwent an MRI scan that was analysed using qualitative measures for cerebral white matter injury/abnormality, and quantitative volumetric techniques with tissue segmentation and regional parcellation for cortical and subcortical grey matter, myelinated and unmyelinated white matter, and cerebrospinal fluid. At ages 4, 6 (corrected for the extent of prematurity), and 9 years (uncorrected), children were screened for behavioural adjustment problems including inattention/hyperactivity symptoms using the parent and teacher rated Strengths and Difficulties Questionnaire (SDQ). At age 9, the Development and Well-Being Assessment (DAWBA) structured psychiatric interview was also completed with primary caregiver and an independent clinical diagnosis of ADHD determined by a child psychiatrist blinded to child’s perinatal history and group status. Results: Agreement between parent and teacher reports regarding child behaviour adjustment was lower for children born very preterm than full-term (mean alternative chance-correlated coefficient, AC₁ = 0.63 vs. 0.80). Across all assessment time-points, very preterm birth was associated with on average a 2-fold increased risk of behavioural inattention/hyperactivity problems. These elevated risks largely reflected high rates of situational symptoms (very preterm = 22.3% − 31.7%; full-term = 10.9% − 16.7%). In contrast, rates of pervasive symptoms were relatively modest (very preterm = 6.8% − 11.5%; full-term = 4.7% − 7.3%). Examination of the predictive validity of inattention/hyperactivity problems identified using parent and teacher reports showed that children exhibiting situational symptoms at ages 4 and 6 were much less likely than those exhibiting pervasive symptoms, for a subsequent clinical diagnosis of ADHD at age 9 years (very preterm = 29% − 47.8% vs. 66.7% − 75%; full-term = 13.3% − 22.2% vs. 33.3% − 40%). Furthermore, receiver operating characteristic curves fitted to the data showed that children born very preterm exhibiting inattention/hyperactivity problems at two or three time-points (area under curve, AUC = .909) have better predictive validity for later ADHD diagnosis, compared to those exhibiting symptoms at age 4 (AUC = .794) or 6 years (AUC = .813) only. Children born very preterm were also at an elevated risk of persistent ADHD symptoms across the ages of 4 to 9 years, with the risk being 5-fold higher than their full-term peers (13.1% vs. 2.8%). Results also revealed possible associations between neonatal neuropathology and later risk of persistent ADHD symptoms. There were no significant linear associations between increasing severity of qualitative neonatal MRI measures of white matter injury/abnormality and very preterm children’s later risk of persistent ADHD symptoms. However, reduction in total cerebral tissue volumes and corresponding increase of cerebrospinal fluid (adjusted for intracranial volume) were significantly associated with increased risk of persistent symptoms in children born very preterm (p = .001). In terms of regional tissue volumes, total cerebral tissues in the dorsal prefrontal region showed the largest volumetric reductions among all the subregions in children born very preterm exhibiting persistent ADHD symptoms, with 3.2 ml (7%) and 8.2 ml (16%) lower tissue volumes than children born very preterm and full-term without persistent symptoms, respectively. Conclusions: Reliance on a single informant to examine child behaviour outcomes at a single time-point may lead to an under- or over-estimation of later ADHD risks. Combining reports from multiple informants and repeated assessments over time may provide better clinical prognostic validity. Children born very preterm are at an increased risk of behavioural inattention/hyperactivity problems during their early school years; although risks of more severe, pervasive problems are relatively modest compared with situational problems. Behavioural adjustment difficulties recognised as early as during preschool age using standardised behaviour screening tools can be a reliable indicator for identifying children born very preterm at risk of subsequent ADHD diagnosis. Finally, study findings suggest that increased risk of ADHD symptoms in children born very preterm can at least in part be accounted for by disturbances to neonatal cerebral growth and maturation.

ADHD affects executive functions and pharmacological treatment is the most common intervention. Medication is ineffective for some and psychosocial interventions are scarcely available. CBT that teaches organizational skills for managing ADHD-symptoms has shown promising results. Smartphones can help individuals perform executive tasks such as planning and organizationand they could beefficacious as a support tool for ADHD patients. The current study is aRCT that compares an online course (n=29) based on previouslyeffective CBT treatments for ADHD to a wait-list control (n=29). Theintervention focused on teaching the use of an online calendar and smartphone apps. The intervention brought significant improvement (p < 0.001) to participants regarding ADHD symptoms and 38% of participants were considered clinically significantly improved. This indicates that online treatments using IT-tools for ADHD is effective and that smartphones can be used as a tool for aiding individuals with impairments in executive functions.

This research investigated elementary classroom teachers' experiences in a collaborative learning community (CLC) on the topic of supporting the literacy learning of students with characteristics of ADHD. Five general education classroom teachers participated in biweekly CLC meetings over a 5-month period. Qualitative methods of data gathering were employed in the form of participant observations in the classroom and during 9 CLC meetings. Participants were also interviewed three times. The first interview was conducted before the CLC meetings began, the second interview was conducted immediately after formal CLC meetings had ceased, and the final interview was conducted 6 months after meetings had ended. Three main findings emerged from the research. First, participants' literacy teaching of their students with characteristics of ADHD was positively influenced as a result of their participation in the CLC. This positive influence came through an interaction of factors related to their knowledge, skills, attitudes, and beliefs. It also resulted from a reconceptualization of both their understanding of their students with characteristics of ADHD and of themselves as literacy teachers. Second, certain aspects of the CLC contributed to this positive outcome. These aspects were the opportunity to work with colleagues, participant control over the format and content of CLC, and repeated opportunities to reflect on and refine teaching practice. Third, personal and contextual factors shaped the participants' experiences within the CLC. Participants who had challenges during their own schooling were more driven and committed to understand and respond to their students’ diverse learning needs. Participants with the most number of years of teaching experience had a more fully realized skill set, higher levels of self-efficacy, and lower levels of stress related to teaching and meeting the needs of their students with characteristics of ADHD. Implications for school literacy teaching, preservice education, in-service education, and future avenues for research are discussed in light of the findings.

[pt] Propomos uma nova solução para o paradoxo de Grossman Stiglitz [1980]. Trocando sua estrutura informacional por uma restrição de desatenção racional, nós mostramos que os preços podem refletir toda a informação disponível, sem quebrar os incentivos dos participantes do mercado em processar informação. Esse modelo reformula a hipótese dos mercados eficientes e concilia visões opostas: preços são completamente reveladores, mas apenas para aqueles que são suficientemente espertos. Finalmente, nós desenvolvemos um método para postular e resolver modelos de equilíbrio geral Walrasiano que circunscreve hipóteses simplificadoras anteriores. / [en] We propose a new solution for the Grossman and Stiglitz [1980] paradox. By substituting a rational inattention restriction for their information structure, we show that prices can reflect all the information available without breaking the incentives of market participants to gather information. This model reframes the efficient market hypothesis and reconciles opposing views: prices are fully revealing but only for those who are sufficiently smart. Finally, we develop a method for postulating and solving Walrasian general equilibrium models with rationally inattentive agents circumventing previous tractability assumptions.

The aim of my dissertation is to map parents´ life who have children with the ADHD syndrome. This presented dissertation consists of the theoretical and practical part. In the theoretical part I am dealing with ADHD syndrome, his definition, characteristics, causes of origin, diagnostics, then I mention difficulties which are connected to ADHD syndrome and his presence in population. Then in chapter Child with ADHD I focus on particularities of its evolution, then I describe the sense and role of the child´s family. The important part is the upbringing ADHD children and, also suitable attitudes for them. I am also dealing with parents who have ADHD child and their potential difficulties, which they can be faced. The last chapter is ADHD Child in the school, where I describe the sense of the teacher for ADHD child and how relations the family and the school have, possibilities how to help, support for parents and their ADHD children. The qualitative method which means interview was chosen for this research. The content of the practical part is to analyse and make dialogues with the parents of ADHD children with the aim to answer on given research questions and to fulfil the aim of my dissertation. Interviews was realised with four respondents. With one of them there was also respondent´s husband. The respondents´ children´s age was from 6 to 12 years, 3 boys and 1 girl. Interviews were rewritten word to word by direct transcription towards written form and subsequently were elaborated by open coding with the subsequent setting cards. Respondents described similar characteristics their children with ADHD as hyperactivity, inattentiveness, impulsiveness and madness. Also they agreed that child´s ADHD negatively influenced the relationship with their partners.

Introdução: O metilfenidato de liberação imediata (MFD-LI) é um psicofármaco receitado mundialmente para o tratamento do Transtorno de Déficit de Atenção/hiperatividade (TDAH). Embora eficaz, o MFD-LI está associado a problemas de adesão ao tratamento, uma vez que os pacientes necessitam ingerir os comprimidos várias vezes ao dia. O Spheroidal Oral Drug Absorption System (SODAS™) é uma formulação de metilfenidato de liberação prolongada (MFD-LP) que mimetiza a administração de MFD-LI duas vezes ao dia, e que apresenta menor flutuação nos níveis séricos. Nesta formulação, cinqüenta por cento dos grânulos com revestimento para liberação entérica são liberados aproximadamente 4 horas após a administração, proporcionando um perfil de ação semelhante a duas tomadas ao dia do MFD-LI. O MFD SODAS™ libera de imediato 50% do medicamento, proporcionando um rápido início de ação quando comparado ao sistema de liberação OROS®. Poucos estudos avaliaram a troca do MFD-LI para o MFD-LP, sendo que desses, apenas crianças e adolescentes foram avaliados, e nenhum verificou os preditores de insatisfação da troca do MFD-LI para o MFD-LP. Objetivos: Este estudo tem como objetivo avaliar os sintomas de TDAH, ou preditores de insatisfação e/ou desistência do tratamento naqueles pacientes clinicamente estáveis que fizeram a troca do MDF-LI para o MFD SODAS™. Método: Os critérios de inclusão foram: diagnóstico de TDAH de acordo com os critérios do DSM-IV, e estabilidade de sintomas com o uso do MFD-LI. Os critérios de exclusão foram: condição clínica coexistente que pudesse impedir a prescrição de MFD SODAS™; diagnóstico de abuso ou dependência de álcool e/ou drogas de abuso; diagnóstico prévio de retardo mental moderado; tratamento psicoterápico concomitante. Este é um ensaio clínico aberto realizado em oito semanas. Os pacientes foram designados a receber doses de MFD SODAS™ de acordo com a dose de MFD-LI previamente estabelecida. A eficácia foi avaliada através das escalas SNAP-IV e CGI-S, e eventos adversos através da Barkley's Side Effect Rating Scale (SERS). Foi solicitado aos participantes que classificassem sua satisfação com o tratamento através de uma escala Likert de 5 pontos. Também foram avaliados os seguintes potenciais preditores de resposta: sexo, idade, etnia, nível socioeconômico, comorbidades, subtipos de TDAH, resultados das escalas SNAP-IV e SERS no baseline, tempo de tratamento, tratamento farmacológico concomitante, dose de MFD-LI prévia ao início do estudo e a existência de pausa do tratamento nos finais de semana. Resultados: A partir de uma amostra total de 207 crianças, adolescentes e adultos (provenientes do ambulatório adulto e infantil de transtorno de déficit de atenção/hiperatividade do Hospital de Clínicas de Porto Alegre) foi possível contatar 133 pacientes, os quais sessenta e dois pacientes foram elegíveis a participar do estudo, e 47 completaram as oito semanas de tratamento. Não se encontrou diferença significativa no escore total do SNAP-IV durante o protocolo - baseline, semana 4 e 8 [F(1, 51,26) =0,012; p=0,913]. Ao todo, 46 (74,2%) dos pacientes relataram estar satisfeitos com o novo tratamento, 16 (25,8%) estavam insatisfeitos ou saíram do protocolo. Nas análises univariadas, foi detectada uma tendência para a associação entre etnia e insatisfação (p=0.05). Não se encontrou uma diferença significativa nos escores da SERS durante o ensaio clínico [F(1, 111,49) =0,748; p=0,389]. Em onze eventos adversos ocorreram ao menos 5% em alguma das avaliações (baseline, 4ª ou 8ª semana). Um adulto, que apresentava uma doença cardiovascular previamente ao estudo, apresentou um acidente vascular cerebral hemorrágico (AVCH) após a quarta semana de tratamento, evoluindo ao óbito após três semanas. Conclusão: Poucos estudos abordaram os sintomas de TDAH após a troca do MFD-LI para qualquer formulação de MFD-LP, e nenhum estudo prévio foi conduzido em populações de países em desenvolvimento ou em amostras com adultos. A taxa de satisfação encontrada (74,2%) na troca do MFD-LI para MFD SODAS™ possivelmente reflete a conveniência da dose única diária deste MFD-LP, como já especulado em estudos prévios. Não foram identificados fatores preditores de insatisfação. O número médio de efeitos colaterais pode ser considerado alto, mas isso pode ser o resultado do uso de uma escala de avaliação adequada, diferentemente do relato espontâneo do evento adverso. Não foi possível encontrar uma relação direta entre os efeitos do MFD SODAS™ e a morte por AVCH ocorrida em um dos sujeitos da amostra. Entretanto, o evento cardiovascular ocorrido sugere extrema cautela ao medicar pacientes com doenças cardiovasculares, conforme proposto pelo FDA. Os achados desse estudo sugerem que o MFD SODAS™ possui eficácia e perfil de eventos adversos similares ao MFD-LI. / Introduction: Immediate-release methylphenidate (MPH-IR) is a pharmacological treatment prescribed worldwide for patients with attention-deficit/hyperactivity disorder (ADHD). The MPH-IR, although highly efficacious, need to be used more than once a day, and consequently might be associated with poor adherence. The Spheroidal Oral Drug Absorption System (SODAS™) is one type of MPH-ER (Extended-release methylphenidate) that mimics the twice-daily administration of MPH-immediate release, but presents less peak and trough fluctuations. This formulation allows the immediate release of 50% of the drug, providing a rapid onset if compared with OROS® formulation. Few studies have evaluated specifically the switching from MPH-IR to MPH-ER. All previous studies accessed only children and adolescents; none evaluated switching to MPH SODAS™ and no predictors of treatment dissatisfaction were mentioned. Objectives: The present study aims to assess ADHD symptoms for 08 weeks after switching from MPH-IR to MPH SODAS™ in clinically stable patients, and to identify predictors of dissatisfaction with MPH SODAS™, and/ or withdrawal from the protocol. Method: The inclusion criteria were: ADHD diagnosis according to the DSM-IV criteria and clinical stability with MPH-IR. The exclusion criteria were: a clinically coexisting medical condition interfering with the administration of MPH SODAS™; previous diagnosis of alcohol and/or drug abuse or dependence; previous diagnosis of moderate mental retardation; concomitant psychotherapy. This is an 8-week open clinical trial. Patients were assigned to doses of MPH SODAS™ according to their pre-study dose of MPH-IR. Assessment of efficacy and side effects was performed by means of the SNAP-IV, CGI-S, Barkley's Side Effect Rating Scale (SERS). Subjects were also asked to report their satisfaction with the treatment in a 5-point Likert scale. We also evaluated the following potential predictors of treatment response: sex, age, ethnicity, socioeconomic status, comorbidities, baseline scores on the SNAP-IV, and SERS, length of treatment, concomitant treatment, previous prescribed dose of MPH-IR, and pause of treatment on weekends. Results: From a total sample of 207 children, adolescents and adults (enrolled from the ADHD outpatient clinic at both Adult and Child and Adolescent Psychiatric Division of Hospital de Clínicas de Porto Alegre) we were able to re-contact 133 patients, where sixty-two patients were eligible to the clinical trial, and 47 completed the 08 weeks of treatment. There was no significant change in the total score of the SNAP-IV during the protocol – baseline, week 4 and 8 [F(1, 51.26)=0.012; p=0.913]. Overall, 46 (74.2%) patients had reported to be satisfied with the new treatment, and 16 (25.8%) were dissatisfied or withdrew from the protocol. In univariate analyses, only ethnicity (p=0.05) were associated with dissatisfaction. No significant change in the SERS score was found during the protocol [F(1, 111.49)=0.748; p=0.389]. Eleven adverse events occurring in at least 5% of the group in any assessment (baseline, 04 or 08 weeks) were observed according to SERS. One adult, with previous cardiovascular disease, presented a hemorrhagic cerebral vascular accident (CVA) after the forth week assessment, resulting in her obit. Conclusion: There is a scarcity of research assessing the switch from MPH-IR to different forms of MPH-ER, and none across the life cycle or in populations from developing countries. The 74.2% of satisfaction with the new treatment may reflect the convenience of the once-a-day dosing of the MPH SODAS™. No predictor of dissatisfaction/withdrawal from the trial was found. The number of adverse events reported during the protocol could be considered high, but this can be the result of the use of an appropriate assessment scale, rather than monitoring only by spontaneous report. It was not possible to find a direc relationship between the MPH SODAS™ and death from a CVA occurred in one of the subjects. However, the cardiovascular event found during the trial, suggest extreme caution when medicating patients with cardiovascular diseases as recently proposed by the FDA. Findings from this study suggest that MPH SODAS™ has similar efficacy and adverse event profile than MPH-IR.

Submitted by Rodrigo dos Santos Barbosa (rdsbar@gmail.com) on 2016-06-13T19:54:58Z No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) / Approved for entry into archive by Letícia Monteiro de Souza (leticia.dsouza@fgv.br) on 2016-06-13T21:06:35Z (GMT) No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) / Made available in DSpace on 2016-06-13T22:04:05Z (GMT). No. of bitstreams: 1 Tese.pdf: 895418 bytes, checksum: 64d50c7a9b78e9d3f89b6737e052eb58 (MD5) Previous issue date: 2016-05-17 / My dissertation focuses on dynamic aspects of coordination processes such as reversibility of early actions, option to delay decisions, and learning of the environment from the observation of other people’s actions. This study proposes the use of tractable dynamic global games where players privately and passively learn about their actions’ true payoffs and are able to adjust early investment decisions to the arrival of new information to investigate the consequences of the presence of liquidity shocks to the performance of a Tobin tax as a policy intended to foster coordination success (chapter 1), and the adequacy of the use of a Tobin tax in order to reduce an economy’s vulnerability to sudden stops (chapter 2). Then, it analyzes players’ incentive to acquire costly information in a sequential decision setting (chapter 3). In chapter 1, a continuum of foreign agents decide whether to enter or not in an investment project. A fraction λ of them are hit by liquidity restrictions in a second period and are forced to withdraw early investment or precluded from investing in the interim period, depending on the actions they chose in the first period. Players not affected by the liquidity shock are able to revise early decisions. Coordination success is increasing in the aggregate investment and decreasing in the aggregate volume of capital exit. Without liquidity shocks, aggregate investment is (in a pivotal contingency) invariant to frictions like a tax on short term capitals. In this case, a Tobin tax always increases success incidence. In the presence of liquidity shocks, this invariance result no longer holds in equilibrium. A Tobin tax becomes harmful to aggregate investment, which may reduces success incidence if the economy does not benefit enough from avoiding capital reversals. It is shown that the Tobin tax that maximizes the ex-ante probability of successfully coordinated investment is decreasing in the liquidity shock. Chapter 2 studies the effects of a Tobin tax in the same setting of the global game model proposed in chapter 1, with the exception that the liquidity shock is considered stochastic, i.e, there is also aggregate uncertainty about the extension of the liquidity restrictions. It identifies conditions under which, in the unique equilibrium of the model with low probability of liquidity shocks but large dry-ups, a Tobin tax is welfare improving, helping agents to coordinate on the good outcome. The model provides a rationale for a Tobin tax on economies that are prone to sudden stops. The optimal Tobin tax tends to be larger when capital reversals are more harmful and when the fraction of agents hit by liquidity shocks is smaller. Chapter 3 focuses on information acquisition in a sequential decision game with payoff complementar- ity and information externality. When information is cheap relatively to players’ incentive to coordinate actions, only the first player chooses to process information; the second player learns about the true payoff distribution from the observation of the first player’s decision and follows her action. Miscoordination requires that both players privately precess information, which tends to happen when it is expensive and the prior knowledge about the distribution of the payoffs has a large variance. / A presente tese concentra-se em aspectos dinâmicos de processos que envolvem coordenação entre agentes em ambientes com interação estratégica. Propomos utilizar os chamados global games para estudar a capacidade de uma Tobin tax elevar a probabilidade de sucesso em um ambiente em que investidores internacionais sujeitos a choques de liquidez precisam coordenar suas decisões de investimento (capítulo 1), e reduzir a vulnerabilidade de uma economia aberta a fluxos internacionais de capitais a sudden stops (capítulo 2). Também, investigamos o problema da aquisição de informação em jogos sequenciais com informação incompleta e complementaridade em ações (capítulo 3). No capítulo 1, agentes estrangeiros decidem se entram ou não em um projeto, cujo sucesso depende em parte da capacidade dos mesmos em coordenarem suas escolhas. Uma fração λ desses investidores é afetada por restrições de liquidez no segundo período do modelo e é forçada a se retirar do projeto ou impedida de entrar, dependendo de suas respectivas escolhas no primeiro período. Agentes não afetados pelo choque de liquidez possuem a opção de reavaliar decisões tomadas no primeiro estágio do jogo. É assumido que a probabilidade de sucesso do projeto de investimento é crescente no volume total de capital que a economia recebe, mas decrescente no volume de capitais que deixa a economia no segundo período. Na ausência de choques de liquidez (λ = 0), o volume de capital que é recebido em um estado pivotal para o sucesso do projeto de investimento independe da existência de um imposto sobre capitais de curto prazo. Como tal imposto sempre desestimula saídas de capitais, uma Tobin tax sempre favorece as chances de sucesso em uma economia em que λ = 0. Contudo, na presença de choques de liquidez, o volume total de investimento que a economia recebe torna-se decrescente em um imposto incidente sobre capitais de curto prazo. Neste caso, uma Tobin tax pode prejudicar as chances do processo de coordenação ser bem sucedido, caso o benefício de reduzir o volume de saída de capitais não seja suficientemente grande. O capítulo 2 estuda os efeitos de uma Tobin tax no mesmo cenário do capítulo 1, porém considera que a extensão da restrição de liquidez a que os agentes podem estar sujeitos é aleatória. Neste modelo, identificamos condições sob as quais uma Tobin tax reduz a probabilidade de se observar um sudden stop e eleva o bem estar no único equilíbrio de uma economia onde a probabilidade de ocorrência de um choque de liquidez é pequena, mas a magnitude de tal choque pode ser significativa. O capítulo final investiga o problema de aquisição de informação em um jogo sequencial com 2 agentes, externalidade informacional e complementaridade em ações. Demonstramos que, quando o custo de aquisição de informação é pequeno relativamente ao incentivo que os agentes possuem para coordenarem suas ações, apenas o primeiro jogador escolhe adquirir novas informações a respeito da distribuição dos payoffs, e o jogador 2 sempre segue a ação escolhida pelo jogador 1. Probabilidade positiva de se observar divergência em ações requer que ambos os jogadores processem informação privadamente, o que tende a ocorrer quando o custo de aquisição de informação é baixo e a distribuição a priori dos payoffs possui variância elevada.

Introdução: O metilfenidato de liberação imediata (MFD-LI) é um psicofármaco receitado mundialmente para o tratamento do Transtorno de Déficit de Atenção/hiperatividade (TDAH). Embora eficaz, o MFD-LI está associado a problemas de adesão ao tratamento, uma vez que os pacientes necessitam ingerir os comprimidos várias vezes ao dia. O Spheroidal Oral Drug Absorption System (SODAS™) é uma formulação de metilfenidato de liberação prolongada (MFD-LP) que mimetiza a administração de MFD-LI duas vezes ao dia, e que apresenta menor flutuação nos níveis séricos. Nesta formulação, cinqüenta por cento dos grânulos com revestimento para liberação entérica são liberados aproximadamente 4 horas após a administração, proporcionando um perfil de ação semelhante a duas tomadas ao dia do MFD-LI. O MFD SODAS™ libera de imediato 50% do medicamento, proporcionando um rápido início de ação quando comparado ao sistema de liberação OROS®. Poucos estudos avaliaram a troca do MFD-LI para o MFD-LP, sendo que desses, apenas crianças e adolescentes foram avaliados, e nenhum verificou os preditores de insatisfação da troca do MFD-LI para o MFD-LP. Objetivos: Este estudo tem como objetivo avaliar os sintomas de TDAH, ou preditores de insatisfação e/ou desistência do tratamento naqueles pacientes clinicamente estáveis que fizeram a troca do MDF-LI para o MFD SODAS™. Método: Os critérios de inclusão foram: diagnóstico de TDAH de acordo com os critérios do DSM-IV, e estabilidade de sintomas com o uso do MFD-LI. Os critérios de exclusão foram: condição clínica coexistente que pudesse impedir a prescrição de MFD SODAS™; diagnóstico de abuso ou dependência de álcool e/ou drogas de abuso; diagnóstico prévio de retardo mental moderado; tratamento psicoterápico concomitante. Este é um ensaio clínico aberto realizado em oito semanas. Os pacientes foram designados a receber doses de MFD SODAS™ de acordo com a dose de MFD-LI previamente estabelecida. A eficácia foi avaliada através das escalas SNAP-IV e CGI-S, e eventos adversos através da Barkley's Side Effect Rating Scale (SERS). Foi solicitado aos participantes que classificassem sua satisfação com o tratamento através de uma escala Likert de 5 pontos. Também foram avaliados os seguintes potenciais preditores de resposta: sexo, idade, etnia, nível socioeconômico, comorbidades, subtipos de TDAH, resultados das escalas SNAP-IV e SERS no baseline, tempo de tratamento, tratamento farmacológico concomitante, dose de MFD-LI prévia ao início do estudo e a existência de pausa do tratamento nos finais de semana. Resultados: A partir de uma amostra total de 207 crianças, adolescentes e adultos (provenientes do ambulatório adulto e infantil de transtorno de déficit de atenção/hiperatividade do Hospital de Clínicas de Porto Alegre) foi possível contatar 133 pacientes, os quais sessenta e dois pacientes foram elegíveis a participar do estudo, e 47 completaram as oito semanas de tratamento. Não se encontrou diferença significativa no escore total do SNAP-IV durante o protocolo - baseline, semana 4 e 8 [F(1, 51,26) =0,012; p=0,913]. Ao todo, 46 (74,2%) dos pacientes relataram estar satisfeitos com o novo tratamento, 16 (25,8%) estavam insatisfeitos ou saíram do protocolo. Nas análises univariadas, foi detectada uma tendência para a associação entre etnia e insatisfação (p=0.05). Não se encontrou uma diferença significativa nos escores da SERS durante o ensaio clínico [F(1, 111,49) =0,748; p=0,389]. Em onze eventos adversos ocorreram ao menos 5% em alguma das avaliações (baseline, 4ª ou 8ª semana). Um adulto, que apresentava uma doença cardiovascular previamente ao estudo, apresentou um acidente vascular cerebral hemorrágico (AVCH) após a quarta semana de tratamento, evoluindo ao óbito após três semanas. Conclusão: Poucos estudos abordaram os sintomas de TDAH após a troca do MFD-LI para qualquer formulação de MFD-LP, e nenhum estudo prévio foi conduzido em populações de países em desenvolvimento ou em amostras com adultos. A taxa de satisfação encontrada (74,2%) na troca do MFD-LI para MFD SODAS™ possivelmente reflete a conveniência da dose única diária deste MFD-LP, como já especulado em estudos prévios. Não foram identificados fatores preditores de insatisfação. O número médio de efeitos colaterais pode ser considerado alto, mas isso pode ser o resultado do uso de uma escala de avaliação adequada, diferentemente do relato espontâneo do evento adverso. Não foi possível encontrar uma relação direta entre os efeitos do MFD SODAS™ e a morte por AVCH ocorrida em um dos sujeitos da amostra. Entretanto, o evento cardiovascular ocorrido sugere extrema cautela ao medicar pacientes com doenças cardiovasculares, conforme proposto pelo FDA. Os achados desse estudo sugerem que o MFD SODAS™ possui eficácia e perfil de eventos adversos similares ao MFD-LI. / Introduction: Immediate-release methylphenidate (MPH-IR) is a pharmacological treatment prescribed worldwide for patients with attention-deficit/hyperactivity disorder (ADHD). The MPH-IR, although highly efficacious, need to be used more than once a day, and consequently might be associated with poor adherence. The Spheroidal Oral Drug Absorption System (SODAS™) is one type of MPH-ER (Extended-release methylphenidate) that mimics the twice-daily administration of MPH-immediate release, but presents less peak and trough fluctuations. This formulation allows the immediate release of 50% of the drug, providing a rapid onset if compared with OROS® formulation. Few studies have evaluated specifically the switching from MPH-IR to MPH-ER. All previous studies accessed only children and adolescents; none evaluated switching to MPH SODAS™ and no predictors of treatment dissatisfaction were mentioned. Objectives: The present study aims to assess ADHD symptoms for 08 weeks after switching from MPH-IR to MPH SODAS™ in clinically stable patients, and to identify predictors of dissatisfaction with MPH SODAS™, and/ or withdrawal from the protocol. Method: The inclusion criteria were: ADHD diagnosis according to the DSM-IV criteria and clinical stability with MPH-IR. The exclusion criteria were: a clinically coexisting medical condition interfering with the administration of MPH SODAS™; previous diagnosis of alcohol and/or drug abuse or dependence; previous diagnosis of moderate mental retardation; concomitant psychotherapy. This is an 8-week open clinical trial. Patients were assigned to doses of MPH SODAS™ according to their pre-study dose of MPH-IR. Assessment of efficacy and side effects was performed by means of the SNAP-IV, CGI-S, Barkley's Side Effect Rating Scale (SERS). Subjects were also asked to report their satisfaction with the treatment in a 5-point Likert scale. We also evaluated the following potential predictors of treatment response: sex, age, ethnicity, socioeconomic status, comorbidities, baseline scores on the SNAP-IV, and SERS, length of treatment, concomitant treatment, previous prescribed dose of MPH-IR, and pause of treatment on weekends. Results: From a total sample of 207 children, adolescents and adults (enrolled from the ADHD outpatient clinic at both Adult and Child and Adolescent Psychiatric Division of Hospital de Clínicas de Porto Alegre) we were able to re-contact 133 patients, where sixty-two patients were eligible to the clinical trial, and 47 completed the 08 weeks of treatment. There was no significant change in the total score of the SNAP-IV during the protocol – baseline, week 4 and 8 [F(1, 51.26)=0.012; p=0.913]. Overall, 46 (74.2%) patients had reported to be satisfied with the new treatment, and 16 (25.8%) were dissatisfied or withdrew from the protocol. In univariate analyses, only ethnicity (p=0.05) were associated with dissatisfaction. No significant change in the SERS score was found during the protocol [F(1, 111.49)=0.748; p=0.389]. Eleven adverse events occurring in at least 5% of the group in any assessment (baseline, 04 or 08 weeks) were observed according to SERS. One adult, with previous cardiovascular disease, presented a hemorrhagic cerebral vascular accident (CVA) after the forth week assessment, resulting in her obit. Conclusion: There is a scarcity of research assessing the switch from MPH-IR to different forms of MPH-ER, and none across the life cycle or in populations from developing countries. The 74.2% of satisfaction with the new treatment may reflect the convenience of the once-a-day dosing of the MPH SODAS™. No predictor of dissatisfaction/withdrawal from the trial was found. The number of adverse events reported during the protocol could be considered high, but this can be the result of the use of an appropriate assessment scale, rather than monitoring only by spontaneous report. It was not possible to find a direc relationship between the MPH SODAS™ and death from a CVA occurred in one of the subjects. However, the cardiovascular event found during the trial, suggest extreme caution when medicating patients with cardiovascular diseases as recently proposed by the FDA. Findings from this study suggest that MPH SODAS™ has similar efficacy and adverse event profile than MPH-IR.

This graduation thesis deals with problems of motivation in children with ADHD (Attention Deficit Hyperactivity Disorder). The theoretical part contains the definition of ADHD, definition, typical symptoms, factors contributing to the emergence of sowing disorder (malfunction) and problems of children with ADHD. The next section describes the motivation, resources and ways to motivate students. The practical part is devoted to research, the technique used was a questionnaire and interview. The research group consisted twenty-five ADHD children from the second degree of primary schools. The research question was set up: Do motivation in children with ADHD from children without the disorder differ any way? The aim was to determine the level of motivation of students with ADHD on school work. This mentioned graduation work will be used to familiarize the public with ADHD problems, this work could serve as an outline of the targeted educational development of motivation of students with ADHD.