Incidence, prevalence, and global burden of ADHD from 1990 to 2019 across 204 countries: data, with critical re-analysis, from the Global Burden of Disease study.

Data on incidence, prevalence and burden of ADHD are crucial for clinicians, patients, and stakeholders. We present the incidence, prevalence, and burden of ADHD globally and across countries from 1990 to 2019 from the Global Burden of Disease (GBD) study. We also: (1) calculated the ADHD prevalence based on data actually collected as opposed to the prevalence estimated by the GBD with data imputation for countries without prevalence data; (2) discussed the GBD estimated ADHD burden in the light of recent meta-analytic evidence on ADHD-related mortality. In 2019, GBD estimated global age-standardized incidence and prevalence of ADHD across the lifespan at 0.061% (95%UI = 0.040-0.087) and 1.13% (95%UI = 0.831-1.494), respectively. ADHD accounted for 0.8% of the global mental disorder DALYs, with mortality set at zero by the GBD. From 1990 to 2019 there was a decrease of -8.75% in the global age-standardized prevalence and of -4.77% in the global age-standardized incidence. The largest increase in incidence, prevalence, and burden from 1990 to 2019 was observed in the USA; the largest decrease occurred in Finland. Incidence, prevalence, and DALYs remained approximately 2.5 times higher in males than females from 1990 to 2019. Incidence peaked at age 5-9 years, and prevalence and DALYs at age 10-14 years. Our re-analysis of data prior to 2013 showed a prevalence in children/adolescents two-fold higher (5.41%, 95% CI: 4.67-6.15%) compared to the corresponding GBD estimated prevalence (2.68%, 1.83-3.72%), with no significant differences between low- and middle- and high-income countries. We also found meta-analytic evidence of significantly increased ADHD-related mortality due to unnatural causes. While it provides the most detailed evidence on temporal trends, as well as on geographic and sex variations in incidence, prevalence, and burden of ADHD, the GBD may have underestimated the ADHD prevalence and burden. Given the influence of the GBD on research and policies, methodological issues should be addressed in its future editions.

Global DNA methylation changes in adults with attention deficit-hyperactivity disorder and its comorbidity with bipolar disorder: links with polygenic scores.

Genetic and environmental factors contribute to the etiology of Attention Deficit-Hyperactivity Disorder (ADHD). In this sense, the study of epigenetic mechanisms could contribute to the understanding of the disorder's neurobiology. Global DNA methylation (GMe) evaluated through 5-methylcytosine levels could be a promising epigenetic biomarker to capture long-lasting biological effects in response to environmental and hormonal changes. We conducted the first assessment of GMe levels in subjects with ADHD (n = 394) and its main comorbidities in comparison to populational controls (n = 390). Furthermore, given the high genetic contribution to ADHD (heritability of 80%), polygenic risk scores (PRS) were calculated to verify the genetic contribution to GMe levels in ADHD and the comorbidities associated with GMe levels. The GMe levels observed in patients were lower than controls (P = 1.1e-8), with women being significantly less globally methylated than men (P = 0.002). Regarding comorbidities, the presence of bipolar disorder (BD) among patients with ADHD was associated with higher methylation levels compared to patients with ADHD without BD (P = 0.031). The results did not change when pharmacological treatment was accounted for in the analyses. The ADHD and BD most predictive PRSs were negatively (P = 0.0064) and positively (P = 0.0042) correlated with GMe, respectively. This study is the first to report an association between GMe, ADHD, and its comorbidity with BD and associations between PRSs for specific psychiatric disorders and GMe. Our findings add to previous evidence that GMe may be a relevant piece in the psychiatric disorders' etiological landscape.

Disentangling the influences of parental genetics on offspring's cognition, education, and psychopathology via genetic and phenotypic pathways.

BACKGROUND: Specific pathways of intergenerational transmission of behavioral traits remain unclear. Here, we aim to investigate how parental genetics influence offspring cognition, educational attainment, and psychopathology in youth. METHODS: Participants for the discovery sample were 2,189 offspring (aged 6-14 years), 1898 mothers and 1,017 fathers who underwent genotyping, psychiatric, and cognitive assessments. We calculated polygenic scores (PGS) for cognition, educational attainment, attention-deficit hyperactivity disorder (ADHD), and schizophrenia for the trios. Phenotypes studied included educational and cognitive measures, ADHD and psychotic symptoms. We used a stepwise approach and multiple mediation models to analyze the effect of parental PGS on offspring traits via offspring PGS and parental phenotype. Significant results were replicated in a sample of 1,029 adolescents, 363 mothers, and 307 fathers. RESULTS: Maternal and paternal PGS for cognition influenced offspring general intelligence and executive function via offspring PGS (genetic pathway) and parental education (phenotypic pathway). Similar results were found for parental PGS for educational attainment and offspring reading and writing skills. These pathways fully explained associations between parental PGS and offspring phenotypes, without residual direct association. Associations with maternal, but not paternal, PGS were replicated. No associations were found between parental PGS for psychopathology and offspring specific symptoms. CONCLUSIONS: Our findings indicate that parental genetics influences offspring cognition and educational attainment by genetic and phenotypic pathways, suggesting the expression of parental phenotypes partially explain the association between parental genetic risk and offspring outcomes. Multiple mediations might represent an effective approach to disentangle distinct pathways for intergenerational transmission of behavioral traits.

Reward- and threat-related neural function associated with risk and presence of depression in adolescents: a study using a composite risk score in Brazil.

BACKGROUND: Neuroimaging studies on adolescents at risk for depression have relied on a single risk factor and focused on adolescents in high-income countries. Using a composite risk score, this study aims to examine neural activity and connectivity associated with risk and presence of depression in adolescents in Brazil. METHODS: Depression risk was defined with the Identifying Depression Early in Adolescence Risk Score (IDEA-RS), calculated using a prognostic model that included 11 socio-demographic risk factors. Adolescents recruited from schools in Porto Alegre were classified into a low-risk (i.e., low IDEA-RS and no lifetime depression), high-risk (i.e., high IDEA-RS and no lifetime depression), or clinically depressed group (i.e., high IDEA-RS and depression diagnosis). One hundred fifty adolescents underwent a functional MRI scan while completing a reward-related gambling and a threat-related face-matching task. We compared group differences in activity and connectivity of the ventral striatum (VS) and amygdala during the gambling and face-matching tasks, respectively, and group differences in whole-brain neural activity. RESULTS: Although there was no group difference in reward-related VS or threat-related amygdala activity, the depressed group showed elevated VS activity to punishment relative to high-risk adolescents. The whole-brain analysis found reduced reward-related activity in the lateral prefrontal cortex of patients and high-risk adolescents compared with low-risk adolescents. Compared with low-risk adolescents, high-risk and depressed adolescents showed reduced threat-related left amygdala connectivity with thalamus, superior temporal gyrus, inferior parietal gyrus, precentral gyrus, and supplementary motor area. CONCLUSIONS: We identified neural correlates associated with risk and presence of depression in a well-characterized sample of adolescents. These findings enhance knowledge of the neurobiological underpinnings of risk and presence of depression in Brazil. Future longitudinal studies are needed to examine whether the observed neural patterns of high-risk adolescents predict the development of depression.

The role of glucocorticoid receptor gene in the association between attention deficit-hyperactivity disorder and smaller brain structures.

ADHD is associated with smaller subcortical brain volumes and cortical surface area, with greater effects observed in children than adults. It is also associated with dysregulation of the HPA axis. Considering the effects of the glucocorticoid receptor (NR3C1) in neurophysiology, we hypothesize that the blurred relationships between brain structures and ADHD in adults could be partly explained by NR3C1 gene variation. Structural T1-weighted images were acquired on a 3 T scanner (N = 166). Large-scale genotyping was performed, and it was followed by quality control and pruning procedures, which resulted in 48 independent NR3C1 gene variants analyzed. After a stringent Bonferroni correction, two SNPs (rs2398631 and rs72801070) moderated the association between ADHD and accumbens and amygdala volumes in adults. The significant SNPs that interacted with ADHD appear to have a role in gene expression regulation, and they are in linkage disequilibrium with NR3C1 variants that present well-characterized physiological functions. The literature-reported associations of ADHD with accumbens and amygdala were only observed for specific NR3C1 genotypes. Our findings reinforce the influence of the NR3C1 gene on subcortical volumes and ADHD. They suggest a genetic modulation of the effects of a pivotal HPA axis component in the neuroanatomical features of ADHD.

Feasibility trial of the dialectical behavior therapy skills training group as add-on treatment for adults with attention-deficit/hyperactivity disorder.

OBJECTIVE: Our aim was to explore the feasibility, and efficacy of a Dialectical Behavior Therapy Skill Training Group (DBT-ST) as an add-on treatment for adult attention-deficit/hyperactivity disorder (ADHD) in Latin America. METHOD: Adults with ADHD (n = 31) with stable medication treatment for ADHD and residual symptoms (ASRS > 20) were randomly assigned to DBT-ST (n = 16) or treatment as usual (TaU; n = 15) for 12 weeks. Feasibility was accessed by attendance and completion rates at 12 weeks. Efficacy outcomes were measured with the ASRS, and performed at 0, 6, 12, and 16 weeks. RESULTS: The DBT-ST protocol had 81.25% completion rate, with a mean attendance of 87.25% of the sessions. No significant interactions between group and time were detected for outcome measures. DISCUSSION: The DBT-ST was feasible as add-on treatment for adult patients with ADHD in Latin America. Replicating previous findings, DBT-ST has shown no significantly higher improvement in ADHD symptoms in comparison with TaU. Registered at the Clinical Trials database (NCT03326427).

Are serum brain-derived neurotrophic factor concentrations related to brain structure and psychopathology in late childhood and early adolescence?

OBJECTIVE: Mental disorders can have a major impact on brain development. Peripheral blood concentrations of brain-derived neurotrophic factor (BDNF) are lower in adult psychiatric disorders. Serum BDNF concentrations and BDNF genotype have been associated with cortical maturation in children and adolescents. In 2 large independent samples, this study tests associations between serum BDNF concentrations, brain structure, and psychopathology, and the effects of BDNF genotype on BDNF serum concentrations in late childhood and early adolescence. METHODS: Children and adolescents (7-14 years old) from 2 cities (n = 267 in Porto Alegre; n = 273 in São Paulo) were evaluated as part of the Brazilian high-risk cohort (HRC) study. Serum BDNF concentrations were quantified by sandwich ELISA. Genotyping was conducted from blood or saliva samples using the SNParray Infinium HumanCore Array BeadChip. Subcortical volumes and cortical thickness were quantified using FreeSurfer. The Development and Well-Being Behavior Assessment was used to identify the presence of a psychiatric disorder. RESULTS: Serum BDNF concentrations were not associated with subcortical volumes or with cortical thickness. Serum BDNF concentration did not differ between participants with and without mental disorders, or between Val homozygotes and Met carriers. CONCLUSIONS: No evidence was found to support serum BDNF concentrations as a useful marker of developmental differences in brain and behavior in early life. Negative findings were replicated in 2 of the largest independent samples investigated to date.

Predictive utility of childhood diagnosis of ICD-10 hyperkinetic disorder: adult outcomes in the MTA and effect of comorbidity.

Diagnostic guidelines differ between DSM attention-deficit/hyperactivity disorder (ADHD) and ICD hyperkinetic disorder (HKD). Only 145 of 579 children age 7-9 in the Multimodal Treatment Study of ADHD (the MTA) with combined-type DSM-IV ADHD met criteria for ICD-10 HKD, because major internalizing comorbidities and more stringent symptom count/pervasiveness requirements excluded most. The 145 HKD had significantly better 14-month medication response than the rest. We explored whether HKD had greater adult symptom persistence and/or impairment than other ADHD. Multi-informant assessments were done for 16 years. We used the 12/14/16-year assessments, in young adulthood. The post-attrition 109 with baseline HKD had no greater adult persistence of ADHD symptoms/impairment than 367 without HKD, but had more cumulative stimulant use, more job losses, lower emotional lability, and fewer car crashes. However, those excluded for internalizing comorbidity but otherwise meeting HKD criteria had significantly more persistence. Only 6 of the 109 (5.5%) with baseline HKD met ICD-10 criteria for HKD in adulthood, compared to 25 of 367 (6.8%) without a childhood HKD diagnosis. Despite greater initial symptom severity, HKD had no worse 16-year young adult outcome than others, except for job losses, balanced by less emotional lability and fewer crashes. Comorbid internalizing disorder seems to have worse prognosis than initial severity/pervasiveness of ADHD symptoms.

Standardised assessment of functioning in ADHD: consensus on the ICF Core Sets for ADHD.

Attention-deficit/hyperactivity disorder (ADHD) is associated with significant impairments in social, educational, and occupational functioning, as well as specific strengths. Currently, there is no internationally accepted standard to assess the functioning of individuals with ADHD. WHO's International Classification of Functioning, Disability and Health-child and youth version (ICF) can serve as a conceptual basis for such a standard. The objective of this study is to develop a comprehensive, a common brief, and three age-appropriate brief ICF Core Sets for ADHD. Using a standardised methodology, four international preparatory studies generated 132 second-level ICF candidate categories that served as the basis for developing ADHD Core Sets. Using these categories and following an iterative consensus process, 20 ADHD experts from nine professional disciplines and representing all six WHO regions selected the most relevant categories to constitute the ADHD Core Sets. The consensus process resulted in 72 second-level ICF categories forming the comprehensive ICF Core Set-these represented 8 body functions, 35 activities and participation, and 29 environmental categories. A Common Brief Core Set that included 38 categories was also defined. Age-specific brief Core Sets included a 47 category preschool version for 0-5 years old, a 55 category school-age version for 6-16 years old, and a 52 category version for older adolescents and adults 17 years old and above. The ICF Core Sets for ADHD mark a milestone toward an internationally standardised functional assessment of ADHD across the lifespan, and across educational, administrative, clinical, and research settings.

The dopamine transporter role in psychiatric phenotypes.

The dopamine transporter (DAT) is one of the most relevant and investigated neurotransmitter transporters. DAT is a plasma membrane protein which plays a homeostatic role, controlling both extracellular and intracellular concentrations of dopamine (DA). Since unbalanced DA levels are known to be involved in numerous mental disorders, a wealth of investigations has provided valuable insights concerning DAT role into normal brain functioning and pathological processes. Briefly, this extensive but non-systematic review discusses what is recently known about the role of SLC6A3 gene which encodes the dopamine transporter in psychiatric phenotypes. DAT protein, SLC6A3 gene, animal models, neuropsychology, and neuroimaging investigations are also concisely discussed. To conclude, current challenges are reviewed in order to provide perspectives for future studies.

Association between irritability and bias in attention orienting to threat in children and adolescents.

BACKGROUND: Irritability, a frequent complaint in children with psychiatric disorders, reflects increased predisposition to anger. Preliminary work in pediatric clinical samples links irritability to attention bias to threat, and the current study examines this association in a large population-based sample. METHODS: We studied 1,872 children (ages 6-14) using the Development and Well-Being Assessment (DAWBA), Childhood Behavior Checklist (CBCL), and dot-probe tasks. Irritability was defined using CBCL items that assessed temper tantrums and hot temper. The dot-probe task assessed attention biases for threat-related (angry face) stimuli. Multiple regression analysis was used to assess specificity of associations to irritability when adjusting for demographic variables and co-occurring psychiatric traits. Propensity score matching analysis was used to increase causal inference when matching for demographic variables and co-occurring psychiatric traits. RESULTS: Irritability was associated with increased attention bias toward threat-related cues. Multiple regression analysis suggests associations between irritability and threat bias are independent from demographic variables, anxiety, and externalizing traits (attention-deficit/hyperactivity, conduct, and headstrong/hurtful), but not from broad internalizing symptoms. Propensity score matching analysis indicated that this association was found for irritable versus nonirritable groups matched on demographic and co-occurring traits including internalizing symptoms. CONCLUSIONS: Irritability in children is associated with biased attention toward threatening information. This finding, if replicated, warrants further investigation to examine the extent to which it contributes to chronic irritability and to explore possible treatment implications.

Psychopathology and friendship in children and adolescents: disentangling the role of co-occurring symptom domains with serial mediation models.

The consolidation of social friendship groups is a vital part of human development. The objective of this study is to understand the direct and indirect influences of three major symptomatic domains-emotional, hyperkinetic, and conduct-on friendship. Specifically, we aim to study if the associations of one domain with friendship may be mediated by co-occurring symptoms from another domain. A total of 2512 subjects aged 6-14 years participated in this study. Friendship was evaluated by the Development and Well-Being Assessment's friendship section. We evaluated two main constructs as outcomes: (1) social isolation and (2) friendship latent construct. Emotional, hyperkinetic, and conduct symptomatic domains were evaluated with the Strengths and Difficulties Questionnaire (SDQ). All SDQ domains were positively associated with social isolation and negatively associated with friendship latent construct in univariate analysis. However, serial mediation models showed that the association between conduct domains with social isolation was mediated by emotion and hyperkinetic domains. Moreover, the associations between emotional and hyperkinetic domains with friendship latent construct in non-isolated children were mediated by the conduct domain. Emotion and hyperkinetic domains were directly and indirectly associated with social isolation, whereas conduct was directly and indirectly associated with overall friendship in non-isolated children. Results suggest that interventions aimed to improve social life in childhood and adolescence may have stronger effects if directed towards the treatment of emotion and hyperkinetic symptoms in socially isolated children and directed towards the treatment of conduct symptoms in children with fragile social connections.

COMT and DAT1 genes are associated with hyperactivity and inattention traits in the 1993 Pelotas Birth Cohort: evidence of sex-specific combined effect.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) symptoms are dimensionally distributed in the population. This study aimed to assess the role of the catechol-O-methyltransferase (COMT) and of the dopamine transporter (DAT1) genes on ADHD symptoms in the general population. METHODS: We investigated 4101 individuals from the 1993 Pelotas Birth Cohort Study using the parent version of the Strengths and Difficulties Questionnaire (SDQ) at ages 11 and 15 years. The SDQ hyperactivity/inattention scores were the main outcomes. RESULTS: Linear regression analyses demonstrated that the increasing number of COMT158Val and DAT1 10R alleles significantly predicted increasing SDQ hyperactivity/inattention scores in boys at both 11 and 15 years of age (ß coefficient = 0.049, t = 2.189, p = 0.029, R2 = 0.012, and ß coefficient = 0.064, t = 2.832, p = 0.005, R2 = 0.008, respectively). The presence of both COMT158Val and DAT1 10R alleles was also associated with full categorical ADHD diagnosis at 18 years of age in boys (χ2 = 4.561, p = 0.033, odds ratio 2.473, 95% confidence interval 1.048-5.838) from this cohort. We did not observe these associations in girls. LIMITATIONS: Our analyses of SDQ hyperactivity/inattention scores were not corrected for SDQ scores of conduct problems because these variables were highly correlated. CONCLUSION: This study demonstrates a role for COMT and DAT1 genes on hyperactivity/inattention symptoms and provides further support for ADHD as the extreme of traits that vary in the population. It also confirms previous evidence for sexual dimorphism on COMT and DAT1 gene expression.

MAP1B and NOS1 genes are associated with working memory in youths with attention-deficit/hyperactivity disorder.

Diverse efforts have been done to improve the etiologic understanding of mental disorders, such as attention-deficit/hyperactivity disorder (ADHD). It becomes clear that research in mental disorders needs to move beyond descriptive syndromes. Several studies support recent theoretical models implicating working memory (WM) deficits in ADHD complex neuropsychology. The aim of this study was to examine the association between rs2199161 and rs478597 polymorphisms at MAP1B and NOS1 genes with verbal working memory in children and adolescents with ADHD. A total of 253 unrelated ADHD children/adolescents were included. The sample was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-4th edition criteria. Digit Span from the Wechsler Intelligence Scale for Children-Third Edition was used to assess verbal WM. The raw scores from both forward and backward conditions of Digit Span were summed and converted into scaled scores according to age. The means of scaled Digit Span were compared according to genotypes by ANOVA. Significant differences in Digit Span scores between MAP1B genotype groups (rs2199161: F = 5.676; p = 0.018) and NOS1 (rs478597: F = 6.833; p = 0.009) genes were detected. For both polymorphisms, the CC genotype carriers showed a worse performance in WM task. Our findings suggest possible roles of NOS1 and MAP1B genes in WM performance in ADHD patients, replicating previous results with NOS1 gene in this cognitive domain in ADHD children.

Serum copeptin in children exposed to maltreatment.

AIM: Childhood maltreatment (CM) has been related to a persistent reprograming of stress-response. Copeptin is a marker of hypothalamic-pituitary-adrenal axis activation; however, few studies have examined copeptin levels in children exposed to CM. The aim of this study was to compare serum copeptin levels in children reporting child abuse and/or neglect and children with no history of CM. METHODS: This study included 65 children with a positive history of moderate to severe CM, as reported by themselves and their parent(s) during a clinical interview, and 71 children with no history of CM as a comparison group. CM was considered moderate to severe based on the child-reported frequency of being exposed to events related to sexual abuse, physical abuse, emotional abuse, emotional neglect, and/or physical neglect. Child psychopathology symptoms were assessed using the Child Behavior Checklist (CBCL). We measured serum copeptin concentration using enzyme-linked immunosorbent assay. RESULTS: Children exposed to CM exhibited higher levels of serum copeptin compared to children without CM when controlling for sex, age, and psychiatric morbidity. The CBCL total score, including internalizing and externalizing symptoms, was higher in children with CM. We found no correlation between copeptin and CBCL scores for internalizing symptoms and externalizing symptoms. CONCLUSION: CM is associated with copeptin serum levels independently of age, sex, and symptom severity. Copeptin is a promising new biomarker for children with a history of abuse and/or neglect.

Predictors of persistence of ADHD into adulthood: a systematic review of the literature and meta-analysis.

Attention-deficit/hyperactivity disorder (ADHD) is traditionally conceptualized as a neurodevelopmental disorder that continues into adulthood in up to half of diagnosed cases. In light of current evidence, factors associated with the course of the disorder remain unknown. We performed a systematic review of the literature searching for risk markers from childhood that predicted the persistence of ADHD into adulthood. We reviewed 26,168 abstracts and selected 72 for full-text review. We identified data from 16 studies, comprising 6 population-based retrospective samples and 10 clinical follow-ups. We performed meta-analyses of factors evaluated by at least three studies. Severity of ADHD (OR 2.33, 95 % CI = 1.6-3.39, p < 0.001), treatment for ADHD (OR 2.09, 95 % CI = 1.04-4.18, p = 0.037), comorbid conduct disorder (OR 1.85, 95 % CI = 1.06-3.24, p = 0.030), and comorbid major depressive disorder (OR 1.8, 95 % CI = 1.1-2.95, p = 0.019) emerged as predictors already presented in childhood for ADHD persistence into adulthood. Further, we suggest that cohort studies should be designed to clarify such an important question for research and clinical practice.

Attentional bias to threat in children at-risk for emotional disorders: role of gender and type of maternal emotional disorder.

Previous studies suggested that threat biases underlie familial risk for emotional disorders in children. However, major questions remain concerning the moderating role of the offspring gender and the type of parental emotional disorder on this association. This study addresses these questions in a large sample of boys and girls. Participants were 6-12 years old (at screening) typically developing children participating in the High Risk Cohort Study for Psychiatric Disorders (n = 1280; 606 girls, 674 boys). Children were stratified according to maternal emotional disorder (none; mood disorder; anxiety disorder; comorbid anxiety/mood disorder) and gender. Attention biases were assessed using a dot-probe paradigm with threat, happy and neutral faces. A significant gender-by-parental emotional disorder interaction predicted threat bias, independent of anxiety and depression symptoms in children. Daughters of mothers with an emotional disorder showed increased attention to threat compared with daughters of disorder-free mothers, irrespective of the type of maternal emotion disorder. In contrast, attention bias to threat in boys only occurred in mothers with a non-comorbid mood disorder. No group differences were found for biases for happy-face cues. Gender and type of maternal emotional disorder predict attention bias in disorder-free children. This highlights the need for longitudinal research to clarify whether this pattern of threat-attention bias in children relates to the risk of developing anxiety and mood disorders later in life.

A cross-sectional study to assess the prevalence of DSM-5 specific learning disorders in representative school samples from the second to sixth grade in Brazil.

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.