Introdução: A dor lombar crônica inespecífica é um importante problema de saúde e de ordem socioeconômica responsável por alto índice de absenteísmo no trabalho e redução do desempenho funcional. A utilização da acupuntura manual como terapia alternativa no tratamento de dor lombar e a eletroacupuntura para potencializar o tratamento, tem se mostrado eficaz, entretanto, com poucas evidências sobre sua efetividade. Objetivo: Comparar a efetividade da eletroacupuntura versus acupuntura manual no tratamento da dor e incapacidade funcional em pacientes com dor lombar crônica inespecífica Método: Sessenta e seis pacientes com dor lombar crônica inespecífica foram distribuídos aleatoriamente em dois grupos: Grupo eletroacupuntura (GE n=33) e grupo acupuntura (GA n=33). Os desfechos clínicos primários foram dor, avaliada com a escala numérica de dor e incapacidade funcional pelo questionário de Incapacidade Roland Morris e os desfechos secundários foram: qualidade da dor medida com o questionário McGill de dor, percepção global com escala da percepção do efeito global, qualidade de vida por meio do Short-Form Health Survey questionnaire (SF-36), depressão com o inventário Beck de Depressão, e cinesiofobia com a Escala Tampa de Cinesiofobia. Os grupos foram tratados duas vezes por semana com duração de 40 minutos, durante seis semanas, totalizando 12 sessões. Foram realizadas três avaliações: inicial, final e follow-up de três meses. O nível de significância foi de alfa < 0,05. Resultados: Ambos os grupos relataram melhora na intensidade da dor e incapacidade funcional, sem diferença entre os grupos. Na intensidade e incapacidade escores de dor entre os grupos foram -0,4 (95% intervalo de confiança [IC] = -1,7 a -0,8) e -2,5 pontos (IC 95% = -5,6 a 0,6), respectivamente. Nos desfechos secundários, observamos uma diferença entre grupos apenas para cinesiofobia (diferença = -4.1 pontos, IC95% = -7,0 a -1,1) no grupo acupuntura manual. Conclusão: A eletroacupuntura e a acupuntura manual são eficazes na melhora da dor e incapacidade funcional em pacientes com dor lombar crônica inespecífica / Introduction: Chronic nonspecific low back pain is significant problem of health and socioeconomic order responsible for high rate of absenteeism at work and reduced functional performance. The use of manual acupuncture as an alternative therapy in the treatment of low back pain and electroacupuncture to enhance the treatment has been proven effective, however, with little evidence of effectiveness. Objective: Compare the effectiveness of electroacupuncture versus manual acupuncture in patients with chronic nonspecific low back pain. Methods: Sixty-six patients with chronic nonspecific low back pain were divided into: electroacupuncture (n=33) and acupuncture group (n=33). The primary clinical outcomes were pain, assessed with the numerical Scale of Pain and functional disability by questionnaire Disability Roland Morris and secondary outcomes were quality of pain measure with the McGill Pain Questionnaire, global perception with the perception of the Global Scale Effect, quality of life through the Short-Form Health Survey questionnaire (SF- 36), depression with the Beck depression inventory, and kinesiophobia with Tampa Scale kinesiophobia. The groups were treated twice a week lasting 40 minutes for six weeks, 12 sessions. Were three evaluations: baseline, post treatment and follow-up of three months. The level of significance was alfa < 0.05. Results: Both groups reported improvements in pain intensity and disability with no difference between groups. Differences in intensity and disability scores of pain between groups were -0.4 (95% confidence interval [CI] = -1.7 to - 0.8) and -2.5 points (95% CI = -5 6 to 0.6), respectively. Regarding secondary outcomes, we observed a difference between-groups for kinesiophobia (difference= -4.1 points, 95% CI - 7.0 -1.1) in acupuncture group. Conclusion: Electroacupuncture and manual acupuncture have similar efficacy in reducing pain and disability in patients with chronic nonspecific low back pain

Objetivo: Comparar a efetividade da atividade gradual versus programa de exercícios supervisionados em pacientes com dor lombar crônica não específica para os desfechos intensidade da dor, qualidade da dor, incapacidade funcional, qualidade de vida, percepção do efeito global, retorno ao trabalho, atividade física, capacidade física e cinesiofobia. Método: Participaram do estudo 66 indivíduos com idade entre 18 a 65 anos com dor lombar crônica não específica, randomizados em dois grupos: Grupo atividade gradual (n=33) e Grupo fisioterapia (n=33). Os desfechos primários foram: intensidade da dor (Escala Numérica de dor) e incapacidade funcional (Questionário de Incapacidade de Roland Morris) e os defechos secundários: Qualidade da dor (Questionário de dor de McGill) qualidade de vida (Short-Form Health Survey Questionnaire), Percepção do Efeito Global (Escala de Percepção do Efeito Global), retorno ao trabalho, atividade física (Questionário de atividade física habitual de Baecke), capacidade física (Teste sentado para de pé e Teste de Caminhada de 15,2 metros), cinesiofobia (Escala Tampa para Cinesiofobia). As intervenções foram individualizadas, com duração de uma hora, por seis semanas e frequência de duas vezes por semana. Cada indivíduo foi avaliado na linha de base e no follow up de seis semanas, três e seis meses após o tratamento. O nível de significância estabelecido foi de ?=0,05. Resultados: Após seis meses, ambos os grupos melhoraram, porém não houve diferença significante entre os grupos para intensidade da dor (média da diferença de 0,1 pontos; IC a 95% -1,1 a 1,5) e incapacidade funcional (média da diferença de 0,0; IC a 95% -2,9 a 3,0). Não foram encontradas diferenças estatisticamente significante entre os grupos para os demais desfechos. Conclusão: Nossos resultados sugerem que atividade gradual e fisioterapia apresentam efetividade similar na redução da intensidade da dor e melhora da incapacidade funcional em pacientes com dor lombar crônica não específica / Objective: To compare the effectiveness of graded activity versus physiotherapy in patients with chronic nonspecific low back pain for pain intensity, quality of pain, disability, quality of life, global perceive effect, return to work, physical capacity and kinesiophobia. Methods: Sixty-six patients between 18 to 65 years old with chronic nonspecific low back pain were randomized into two groups: Graded activity group (n=33) and physiotherapy group (n = 33). The primary outcomes were: Intensity pain (Numerical Pain Scale) and disability (Roland Morris Disability Questionnaire). The secondary outcomes were: Quality of pain (McGill Pain Questionnaire), quality of life (Short-Form Health Survey Questionnaire), Global perceived effect (Global perceived effect scale), return to work, physical activity (Baecke Questionnaire of Habitual Physical Activity), physical capacity (sit-to-stand test and 15.24m walk test) and kinesiophobia (Tampa Scale of Kinesiophobia) The intervention was individualized, twice a week, one hour for six weeks. The participants were assessment for a blind assessor in the baseline and six weeks, three and six month\'s follow-up. The level of significance was established in ?=0.05. Results: After six weeks, both groups improved, but we not observed significance difference between groups (mean difference 0.1 points; CI 95% -1.1 a 1.5) and disability (mean difference 0.0; IC a 95% -2.9 a 3.0). We not observed statistical difference between groups for all outcomes. Conclusion: Our study provide high quality evidence that graded activity and physiotherapy have similar effectiveness reducing intensity pain and disability in patients with chronic nonspecific low back pain

Estudo de fase III, prospectivo, aleatorizado e duplo-cego de prevenção de mucosite oral com laser de baixa potência. Foram incluídos pacientes portadores de câncer de cabeça e pescoço, tratados com radioquimioterapia. Grupo A laser 2,5 J/cm2 diariamente durante o tratamento e grupo B laser placebo. Inclusão de 75 pacientes (A/B 37/38). Grau III /IV mucosite: A/B 2a semana (4/5) P=1.0, 4a semana (4/12) P=0.04 e 6a semana (8/9) P=1.0. Interrupções da RT devido à mucosite A/B 0/6 P=0.02. Dor severa A/B 2a semana (5/5), 4a semana (8/8) e 6a semana (8/8) P=1.0. O tratamento com laser foi efetivo, tendo adiado o aparecimento da mucosite severa e reduzido as interrupções da radioterapia. / Phase III, prospective, randomized, double-blind study of oral mucositis prophylaxis by low energy laser. Patients included had a diagnosis of head and neck cancer and were managed with radiochemotherapy. Arm A laser 2.5 J/cm2 daily throughout treatment and B sham laser. Inclusion of 75 patients (A/B 37/38). Grade III /IV mucositis A/B: week 2 (4/5) P=1.0, week 4 (4/12) P=0.04 and week 6 (8/9) P=1.0. Treatment breaks due to mucositis A/B 0/6 P=0.02. Severe pain A/B week 2 (5/5), week 4 (8/8) and week 6 (8/8) P=1.0. Low laser therapy was effective, delaying severe mucositis and reducing radiotherapy breaks.

L’Afrique sub-saharienne (SSA) se caractérise par une croissance démographique rapide et une pauvreté notoire. Cette région du monde fait face à une charge de morbidité causée à la fois par les maladies infectieuses traditionnelles et par l’émergence des maladies chroniques. Les essais contrôlés randomisés (ECR) prenant en compte le contexte local sont nécessaires pour renforcer les politiques de santé publique et améliorer l’état de santé des populations. Toutefois à cause des capacités limitées de recherche, les ECR conduits en ASS doivent répondre à des questions prioritaires, les biais (erreurs systématiques) doivent être évités dans les méthodes, et les interventions de santé évaluées doivent être décrites de manière pour faciliter leur implémentation dans la pratique clinique courante. Ces mesures permettent d’éviter le « gâchis de la recherche ». Nos objectifs étaient de décrire l’épidémiologie des ECR conduits en ASS, et d’évaluer la qualité méthodologique (risque de biais) ainsi que le « reporting » des interventions évaluées. Nos travaux ont montré d’une part qu’en ASS, les ECR portent fréquemment sur les maladies à forte morbi-mortalité dans cette région ; mais que les financements des recherches effectuées proviennent surtout des pays à haut revenu (Europe occidentale et Amérique du Nord), et que les auteurs correspondants sont majoritairement affiliés aux institutions des pays à haut revenu. D’autre part, nous avons montré que les méthodes à haut risque de biais peuvent être évitées au moyen d’ajustements méthodologiques simples au coût mineur. L’amélioration de la qualité méthodologique des ECR conduits en ASS implique une large diffusion des méthodes à faible risque de biais ainsi que celle des recommandations pour la description complète des interventions. En outre, une compréhension des barrières et des facilitateurs à l’adhérence à ces méthodes et à ces recommandations est également nécessaire. / Sub-saharan Africa (SSA) is characterized by a high population growth and a significant poverty. In addition, this area deals with a burden of disease due to both traditional infection diseases and the emerging chronic diseases. Randomised controlled trials (RCTs) taking into account the local context are needed to strength health policy and to improve the population health. However, because of constraint research capacities, RCTs performed in SSA must investigate relevant research questions, biases must be avoided in methods, and health interventions evaluated must be reported completely for easing implementation in current clinical practice. Such efforts help to avoid waste of research. Our objectives were to describe the epidemiology of SSA RCTs, and then to evaluate the methodological quality as well as the reporting of evaluated interventions. On the one hand, our works highlighted that SSA RCTs mainly focused on diseases of the highest burden in that area, although they were frequently funded by high-income countries, and most of the corresponding authors were affiliated to those countries. In the other hand, we have shown that methods at high risk of bias can be avoided through simple methodological adjustments of minor cost. Improving the methodological quality of SSA RCTs implies a large dissemination of available methods at low risk of bias and guidelines on the complete reporting of interventions. Furthermore, understanding barriers and facilitators to the uptake of those methods and guidelines is equally required.

Introduction : La majorité des enfants ayant l’anémie falciforme (AF) sont déficients en vitamine D. Cette déficience causerait ou exacerberait possiblement les complications de l’AF telles que les crises de douleur et les complications osseuses. Nous avons récemment publié que près de 70% des enfants suivis à notre clinique d’AF étaient déficients en vitamine D (<50 nmol/L), que ceux-ci avaient de faibles apports alimentaires en vitamine D et prenaient peu de suppléments. Cliniquement, les enfants déficients en vitamine D avaient un moins bon profil hématologique que les enfants suffisants en vitamine D. Ces résultats nous ont amené à proposer une intervention pour résoudre ces problèmes. Objectifs : Primaires : Évaluer la faisabilité, l’acceptabilité et la sécurité d’un bolus oral de 300 000 UI de vitamine D3, chez les enfants ayant l’AF, combiné à une supplémentation quotidienne de 1 000 UI de vitamine D3 pour 3 mois. Secondaires : Évaluer le changement des taux sériques de 25(OH)D après 3 mois ainsi que les impacts cliniques d’une telle supplémentation. Méthode : Des enfants avec AF (5 à 17 ans, tous les génotypes) ont été randomisés à un bolus oral de vitamine D3 (300 000 UI) ou à un placebo. Tous les enfants ont également reçu une prescription pour des comprimés de 1 000 UI vitamine D3 à prendre quotidiennement. La 25(OH)D sérique a été mesurée au début de l’étude et 3 mois post-bolus (efficacité de l’intervention). Les autres paramètres mesurés lors de l’étude étaient le ratio calcium/créatinine urinaire et le calcium sérique (sécurité), la douleur musculosquelettique, la qualité de vie, l’hématologie et les marqueurs osseux (paramètres cliniques exploratoires). Résultats : Trente-huit enfants ont participé à l’étude (âge moyen de 10,1 +/- 3,6 ans; 63% HbSS, 29% HbSC et 8% S/β thal+) : 18 ont reçu le bolus de vitamine D et 20 le placebo. Au début de l’étude, les niveaux moyens de 25(OH)D étaient de 75 +/- 27 nmol/L et 50% des enfants étaient insuffisants en vitamine D (<75 nmol/L). Chez les enfants ayant pris le bolus, les taux de 25(OH)D se sont élevés à 94 nmol/L après 3 mois et le taux d’insuffisance en vitamine D est descendu à 17%, alors que pour le placebo, les taux de 25(OH)D post 3 mois étaient de 74 +/- 19 nmol/L et le taux d’insuffisance en vitamine D était de 45% (p=0,001). Aucun épisode d’hypercalcémie, d’hypercalciurie ou d’hypervitaminose D (>250 nmol/L) n’a eu lieu durant l’étude, mais les enfants du groupe bolus ont expérimenté plus de symptômes gastro-intestinaux dans le premier mois suivant l’ingestion du bolus, comparativement au groupe placebo. Le décompte de réticulocytes était plus faible à la fin de l’étude pour les enfants du groupe bolus. Aucun autre effet clinique de l’intervention n’a été observé. Conclusion : L’utilisation d’un bolus de vitamine D à haute dose combiné à une supplémentation quotidienne en vitamine D chez des enfants ayant l’AF était plus efficace à élever les taux de 25(OH)D à des taux supérieurs à 75 nmol/L que la supplémentation quotidienne seule. Des études multicentriques à plus grande échelle et de plus longue durée sont nécessaires afin d’évaluer les effets cliniques d’une telle supplémentation. / Background: Most children with sickle cell disease (SCD) are vitamin D deficient. This deficiency could possibly cause or exacerbate SCD complications such as pain crisis and bone complications. We previously showed that nearly 70% of children followed in our SCD Clinic were vitamin D deficient (<50 nmol/L) with low vitamin intake and poor use of supplements. Clinically, worse hematological profile was seen in vitamin D-deficient children compared to vitamin D-sufficient children. This study was designed to overcome these issues. Objectives: Primary objectives were to assess feasibility, acceptability, and safety of a single oral bolus of 300,000 IU of vitamin D3 combined to daily 1,000 IU vitamin D3 for 3 months in children with SCD. Secondary objectives were to asses the mean change in serum 25(OH)D from baseline to 3 months post-bolus and its clinical impact. Procedure: A randomized controlled trial was carried out in children with SCD (5-17 years, all genotypes). Children were randomized to a single bolus of vitamin D3 (300,000 IU) or placebo and also received prescription for daily 1,000 IU vitamin D3. Serum 25OHD (efficacity outcome) was measured at baseline and 3 months post-bolus. Other outcomes measured were urinary calcium/creatinine ratio and serum calcium (safety), musculoskeletal pain, quality of life as well as hematology and bone markers (exploratory outcomes). Results: Thirty-eight children were randomized to received the vitamin D bolus (n=18) or the placebo (n=20) (mean age 10.1 +/- 3.6 years; 63% HbSS, 29% HbSC and 8% S/β thal+). At baseline, 50% of the children were vitamin D insufficient (<75 nmol/L) and mean serum 25(OH)D levels were 75 +/- 27 nmol/L. In the vitamin D bolus group, insufficiency dropped to 17% post 3 months and mean 25(OH)D levels raised to 94 nmol/L. In children who took the placebo, rates of vitamin D insufficiency were 45% and mean 25(OH)D levels were 74 +/-19 nmol/L post 3 months (p=0.001). The vitamin D bolus caused no hypercalcemia, hypercalciuria nor hypervitaminosis D (>250 nmol/L). However compared to the placebo group, more children in the bolus group experienced gastro-intestinal symptoms within the first month following the vitamin D bolus. As for the hematology parameters, only a slight difference in reticulocytes counts was observed with lower reticulocytes count the end of the study in children from the bolus group. No other clinical effects of the intervention were observed. Conclusions: High-dose vitamin D bolus combined to daily supplementation in children with SCD is more efficient than daily supplementation alone to raise 25(OH)D levels ≥75 nmol/L. Large-scale multicenter studies of longer duration are needed to assess whether this intervention can improve clinical outcomes of children with SCD.

<p>We followed up with about 2,000 smallholder households in Senegal, two years after these households participated in a randomized controlled trial (RCT) aimed at reducing levels of aflatoxins in smallholders’ stored maize. In the initial intervention, treated households were provided with training on proper post-harvest practices, low-cost moisture meters for testing if maize was sufficiently dry to store, plastic tarps for drying maize of the ground, and hermetic (airtight) storage bags to mitigate aflatoxin development in stored maize. Using cross-sectional follow up data on aflatoxins levels and drying and storage practices from 2019 along with baseline demographic data from 2016, we estimate both the longer-term intention-to-treat (ITT) effects and the treatment on the treated (TOT) effects that the four inputs provided on households’ aflatoxins levels in stored maize. The ITT analyses estimate the intervention’s average effect by treatment group, but this may underestimate the true impact for households who complied with recommended post-harvest practices and adopted the recommended technologies. The TOT analyses estimate the local average treatment effects (LATE) of the intervention, that is its impacts on those who were driven by the intervention to follow best practices or use a given technology. Since the decision to follow these practices or adopt a technology was not random, we instrumented the usage decision with the exogenous, random treatment group assignment to get an unbiased estimate. Outside of our main models, we conducted a heterogeneity analysis to test if households with different characteristics benefit differently from the intervention. We interacted each treatment assignment with various household characteristics, including the woman’s level of involvement in the intervention. Additionally, we estimate the cost-effectiveness of providing training and a tarp, according to WHO guidelines for public health interventions. </p>

The effectiveness of memory specificity training (MeST) was compared with standard cognitive processing therapy (CPT) in treatment of individuals with posttraumatic stress disorder. Eighteen adults aged 18-36 were randomly assigned to the MeST intervention (n = 9) or to the active control group (n = 9) of CPT. Both treatments were administered in group format across 6 weeks. MeST consisted of 6 weekly sessions, while CPT consisted of 12 biweekly sessions. The trial was undertaken in the Psychology Clinic of the University of North Texas, with randomization to conditions accomplished via computer random number generator. The primary outcome measure was change in PTSD symptoms post-treatment from baseline. Sixteen individuals (13 women and 3 men; MeST n = 8 and CPT n = 8) completed treatment and their data was analyzed. MeST significantly decreased PTSD symptomology at post-treatment and these results were maintained at 3 months post-treatment. MeST was found to be as effective as the established CPT intervention at reducing PTSD symptomology. Both MeST and CPT significantly increased participants' ability to specify memories upon retrieval at post-treatment, with results maintained at follow-up. There were no significant effects of MeST or CPT in ability to increase overall controlled cognitive processing at post-treatment or follow-up. No individual in either group reported any adverse effects during treatment or at 3 months follow-up. MeST appears to hold promise as an efficacious treatment option for PTSD. MeST was as effective as CPT in reducing symptoms of PTSD, but required only half the number of treatment sessions to accomplish these gains. Replication of these findings in larger samples is encouraged.

No description available.

Parce qu’il favorise l’initiation précoce du traitement qui limite la morbi-mortalité et les transmissions secondaires, le dépistage du VIH est essentiel au contrôle de l’épidémie. En France, plusieurs milliers de personnes ignorent encore leur séropositivité et un quart des diagnostics du VIH est tardif. La participation infirmière au dépistage du VIH suscite un vif intérêt car elle permet d’élargir les acteurs impliqués. Nous avons suggéré à partir d’une revue de littérature systématique que, dans les pays à épidémie concentrée du VIH comme la France, les Etats Unis ou le Royaume Uni, les infirmiers pouvaient renforcer l’offre et la réalisation du dépistage du VIH. Dans ces pays, les autorités de santé ont préconisé un dépistage généralisé (non ciblé) du VIH dans les structures de santé non spécialisées. En raison de son efficacité modeste et de la charge de travail associée, cette recommandation a progressivement été remise en cause. L’étude DICI-VIH a été conçue pour explorer un nouveau mode, ciblé, de dépistage du VIH par les infirmiers dans les services d’urgences d’Ile-de-France, une région à forte prévalence. Nous avons montré, à l’aide d’un essai à large échelle randomisé en cluster et crossover en deux périodes, que ce mode de dépistage constitue une approche intéressante. En optimisant l’utilisation des ressources consacrées au dépistage dans les services d’urgences, cette stratégie ciblant un nombre limité de patients est réalisable et efficace pour identifier les personnes qui ne connaitraient pas leur séropositivité et, de plus, son coût est limité. Ces résultats fournissent de nouvelles données permettant l’adaptation des stratégies de dépistage du VIH proposées dans les régions où l’épidémie est concentrée. Ils participent également à l’évaluation de l’implication infirmière dans les programmes de dépistage. / Screening is essential to controlling the HIV epidemic as it ensures early treatment initiation, which limits morbidity, mortality and secondary transmission. In France, thousands of individuals remain unaware of their HIV status and a quarter of diagnoses occur at a late stage of infection. Nurse participation in HIV screening is widely discussed as a means by which to get a greater number of actors involved. Through a systematic review we suggested that, in countries with concentrated epidemics such as France, the United States and the United Kingdom, nurses could increase the number of screening tests being offered and performed. In these countries, Health authorities have recommended non-targeted systematic HIV screening in non-specialized health care settings. While this recommendation has gradually been questioned due to its limited effectiveness and associated increased workload, the DICI-VIH trial was designed to explore a new targeted method of HIV screening, performed by nurses in the Emergency Departments of the Paris metropolitan area, where HIV prevalence is high. A large-scale trial with a cluster-randomized two-period crossover design showed that this screening strategy is a compelling approach. By limiting the use of resources allocated to screening in Emergency Departments and by targeting a limited number of patients, this strategy is shown to be feasible and effective in identifying individuals who are unaware of their HIV status. It is also associated with limited costs. These results contribute new data to the discussion on how to best adapt HIV screening strategies in contexts where the epidemic is concentrated and to the evaluation of the contribution of the nursing profession to screening programs.

Thèse de doctorat présentée en vue de l'obtention du doctorat en psychologie (Ph.D) / Depuis les dernières années, un problème en particulier semble de plus en plus reconnu par les différents acteurs de la santé et des services sociaux : l’anxiété de performance scolaire. Elle se définit par un ensemble de réponses cognitives, physiologiques et comportementales à un contexte d’évaluation scolaire. Les études relèvent que jusqu’à 43 % des jeunes vivraient de l’anxiété de performance scolaire modérée à élevée. L’anxiété de performance scolaire est un problème complexe et multifactoriel. Malgré le peu de recherches longitudinales sur le sujet, différentes associations ont été observées concernant notamment le rôle de facteurs individuels (genre féminin, distorsions cognitives et préoccupations perfectionnistes, comportements d’évitement, stratégies d’étude inefficaces, etc.) et de facteurs environnementaux (manque de soutien parental, promotion d’aspirations extrinsèques de la part des parents ou du milieu scolaire, négativité du personnel enseignant, environnement de classe compétitif). Ces facteurs contribueraient au développement de l’anxiété de performance scolaire et à son maintien. La littérature montre que ce type d’anxiété engendre plusieurs conséquences négatives, telles que des difficultés psychologiques et scolaires. Bien que les chercheurs s’intéressent de plus en plus à l’anxiété de performance scolaire, à notre connaissance, aucun programme validé n’a encore été développé pour ce problème dans les écoles secondaires du Québec. Dans ce contexte, l’objectif de cette thèse était d’abord de développer une intervention basée sur les données probantes pour réduire l’anxiété de performance scolaire, soit le programme Pastel. Ce programme est une intervention brève de groupe d’approche cognitivo-comportementale pour les adolescents, combinant l’apprentissage d’habiletés d’étude et d’organisation. Cette thèse comporte cinq chapitres. Le premier chapitre est une introduction générale permettant de situer le contexte de cette recherche. Le deuxième chapitre présente le contexte théorique sous la forme d’un chapitre de livre. Le troisième chapitre, sous forme d’un article, présente les résultats de l’évaluation des effets du programme Pastel l, tandis que le quatrième chapitre, également sous forme d’un article, présente les résultats de l’évaluation des mécanismes de changement du programme. Plus précisément, à l’aide d’un devis randomisé contrôlé composé de 48 adolescents répartis en deux groupes (intervention et contrôle), les résultats montrent une réduction de l’anxiété de performance scolaire à court terme plus importante chez les adolescents ayant participé au programme comparativement aux participants du groupe contrôle. Un large effet est également observé chez les participants du groupe d’intervention entre le pré-test et le post-test, ainsi qu’entre le pré-test et le suivi six mois plus tard (chapitre III). Des analyses qualitatives se basant sur des entrevues de groupe réalisées auprès de 21 participants et des entrevues individuelles réalisées auprès de neuf animateurs ont permis d’identifier onze thèmes pouvant expliquer les effets bénéfiques du programme, soit six qui concernent les mécanismes de changement spécifiques : 1) capacités d’auto-observation, 2) distorsions cognitives, 3) résolution de problèmes, 4) comportements d’évitement, 4) habiletés d’organisation et d’étude et 5) gestion des tensions physiologiques, ainsi que cinq qui concernent les mécanismes de changement généraux : 1) format de groupe, 2) motivation et engagement, 3) renforcement, 4) matériel adapté aux participants et 5) schèmes relationnels (chapitre IV). Finalement, le dernier chapitre de cette thèse présente une discussion générale ainsi qu’une courte conclusion. / In recent years, one problem in particular seems to have been increasingly recognized by the health and social services actors: test anxiety. It is defined by cognitive, physiological and behavioral responses in an academic assessment context. Studies show that up to 43% of adolescents experience moderate to high levels of test anxiety. Test anxiety is a complex and multifactorial problem. Despite the lack of longitudinal research on the subject, different associations have been observed with regard to individual factors (female gender, cognitive distortions and perfectionist concerns, avoidance behaviors, ineffective study skills) and environmental factors (lack of parental support, promotion of extrinsic aspirations by parents or school environment, negativity of teachers, competitive classroom environment). These factors can contribute to the development and maintenance of test anxiety. The literature shows that this type of anxiety has several negative consequences such as psychological and academic difficulties. Although an increasing amount of research is being conducted on test anxiety, to our knowledge, no validated program has yet been developed for test anxiety in Quebec high schools. In this context, the objective of this thesis was to develop an evidence-based intervention to reduce test anxiety, namely the Pastel program. Based on a cognitive-behavioral approach combining study skills, this program is a brief group intervention for adolescents. This thesis consists of five chapters. The first chapter is a general introduction of the context of this research. The second one presents a theoretical background of test anxiety in the form of a book chapter. The third chapter, in the form of an article, presents the results of the evaluation of the effects of the Pastel program, while the fourth chapter, also in the form of an article, presents the results of the evaluation of the mechanisms of change. More specifically, we used a randomized controlled trial composed of 48 adolescents divided into two groups (intervention vs control). The results show a greater decrease in short-term of test anxiety in adolescents who participated in the program in contrast to participants in the control group. A larger effect is also observed among participants in the intervention group between pretest and post-test, as well as between pretest and the six-month follow-up (chapter III). Qualitative analyzes based on group interviews with 21 participants and individual interviews with nine animators identified eleven themes that could explain the beneficial effects of the program. Five are related to specific mechanisms of change: 1) self-observation skills, 2) cognitive distortions, 3) problem-solving, 4) avoidance behaviors, 5) organizational and study skills, and 6) management of physiological stress, and five are related to general mechanisms of change: 1) group format, 2) motivation and commitment, 3) reinforcement, 4) material adapted to the participants and 5) relational schemes (chapter IV). Finally, the last chapter of this thesis presents a general discussion and a short conclusion.