Little is known about specific learning disorder (SLD) in low- and middle-income countries (LMICs), and even less from representative school samples in small size cities outside huge urban centers. Few studies addressed the new DSM-5 criteria for SLDs. We investigated the prevalence of DSM-5 SLDs, their comorbidities and correlates in school samples of students from the second to sixth grades living in median cities from four different geographic regions in Brazil. A national test for academic performance covering reading, writing and mathematical abilities was applied. Psychiatric diagnoses were assessed by the K-SADS-PL applied to the primary caregiver. A total of 1618 children and adolescents were included in the study. The following prevalence rates of SLDs were found: 7.6% for global impairment, 5.4% for writing, 6.0% for arithmetic, and 7.5% for reading impairment. Attention-deficit/hyperactivity disorder (ADHD) was the only comorbidity significantly associated with SLD with global impairment (p = 0.031). Anxiety disorders and ADHD were associated with SLD with arithmetic impairment. Significant differences were detected in prevalence rates among cities, and several socio-demographic correlates (age, gender, IQ, and socioeconomic status) were significantly associated with SLD with global impairment in our sample. Careful validation and normatization of instruments to assess academic performance is a major problem in LMICs. As expected, we found a significant heterogeneity in prevalence rates of SLD according to geographic regions considering that Brazil is a country with a robust diversity. SLD with global and arithmetic impairment was significantly associated with psychiatric comorbidities.

Early vulnerabilities such as low IQ, presence of disability, and dimensions of temperament were associated with psychiatric disorders among Brazilian elementary school children, after controlling for familial and ecological confounders. These early vulnerabilities should be considered in mental health prevention/intervention programs in low-middle-income countries like Brazil.

AgradecimentosÀ minha família, base principal da minha vida, pelo amor e apoio sem fim: à minha mãe Sandra, por ser sempre tão guerreira e ter me transmitido um pouco dessa garra, além de toda ajuda, mesmo nos momentos mais delicados da sua vida; ao meu pai Luiz Paulo, por todo suporte, sendo este na área acadêmica ou pessoal, que com certeza me ajudou e muito para que eu chegasse até aqui; e à minha irmã Luciana, minha companheira de todas as horas, por ser meu racional quando precisei e pelas gargalhadas intermináveis, na alegria e na tristeza.Ao Mercadante, por ter aberto as portas para que todo esse processo fosse possível de acontecer.Ao Rohde, por ter sido o melhor orientador que eu poderia ter após a perda de uma pessoa tão querida. Obrigada por todas as orientações quando precisei, assim como os esclarecimentos de todas as minhas dúvidas, sempre tão prontamente.Ao Prof. Euri, agradeço de coração, por ter me acolhido quando realmente precisei e por todo aprendizado científico durante estes anos da minha jornada acadêmica. À toda minha família Saldanha e Fortes e especialmente aos meus avós MariaRegina e Francisco, aos meus tios Cláudio, Helena e Alex, e ao meu primo Henrique por terem acompanhado de perto todo o processo e por me incentivarem a continuar em frente sempre, mesmo diante de pedras no caminho.