Exploring the relationship between admixture and genetic susceptibility to attention deficit hyperactivity disorder in two Latin American cohorts.

Contemporary research on the genomics of Attention Deficit Hyperactivity Disorder (ADHD) often underrepresents admixed populations of diverse genomic ancestries, such as Latin Americans. This study explores the relationship between admixture and genetic associations for ADHD in Colombian and Mexican cohorts. Some 546 participants in two groups, ADHD and Control, were genotyped with Infinium PsychArray®. Global ancestry levels were estimated using overall admixture proportions and principal component analysis, while local ancestry was determined using a method to estimate ancestral components along the genome. Genome-wide association analysis (GWAS) was conducted to identify significant associations. Differences between Colombia and Mexico were evaluated using appropriate statistical tests. 354 Single-nucleotide polymorphisms (SNPs) and Single-nucleotide variants (SNVs) related to some genes and intergenic regions exhibited suggestive significance (p-value < 5*10e-5) in the GWAS. None of the variants revealed genome-wide significance (p-value < 5*10e-8). The study identified a significant relationship between risk SNPs and the European component of admixture, notably observed in the LOC105379109 gene. Despite differences in risk association loci, such as FOXP2, our findings suggest a possible homogeneity in genetic variation's impact on ADHD between Colombian and Mexican populations. Current reference datasets for ADHD predominantly consist of samples with high European ancestry, underscoring the need for further research to enhance the representation of reference populations and improve the identification of ADHD risk traits in Latin Americans.

Effects of comorbidity on executive functions among children with ADHD, finding trends.

There is still no basic overview about the effect of various types of comorbidity in executive functions due to two main reasons: (1) the type and number of comorbidities in ADHD is significantly varied, (2) EFs are very diverse and have different neuropsychological properties. Our objective was to determine the effect of comorbid disorders (number and type) on the performance in a wide range (seven) of executive functions in a sample of children with ADHD. Fifty-five male children aged seven to nine years with ADHD were divided into six groups: G1 = ADHD only (ADHD-O), G1 = Oppositional defiant disorder (ODD), G3 = (anxiety/depressive disorder (ADD), G4 = ODD + ADD, G5 = ODD + learning disorder (LD), G6 = ODD + LD + conduct disorder (CD). The six groups exhibited different number of deficits in EFs; G1 showed only 1 deficit in contrast, G6 presented 11. Statistical analysis (ANOVA and logistic regression) identified three most affected EFs: Working memory, generation/classification of semantic categories, and inhibitory control. Alterations in EFs increased mainly in relation to the increase of the specific number and type of comorbidity. To date, no studies have addressed comorbidity from this perspective. A wide range approach of EF confirms the need to further study comorbidity in ADHD from a wide range/variety perspective and determine all possible combinations (number/type) to clarify its contribution to the complex neuropsychology functioning in ADHD.

Learning Process During Risk Detection in Adolescents With ADHD.

OBJECTIVE: To evaluate and describe the performance during the learning process of risk-detection versus risk-benefit processing in adolescents diagnosed with ADHD. METHOD: Thirty-five adolescents with ADHD and 26 paired controls participated. The tests applied are Iowa-type children version paradigm and Stroop test. RESULTS: Adolescents with ADHD exhibited lower risk-benefit processing capacity and lower ability to detect risk selections; main findings also indicate that adolescents with ADHD were slower to learn to avoid risk choices. In addition, they also presented a deficient inhibitory control. CONCLUSION: Results confirm the presence of a deficit in advantageous choice in adolescents with ADHD. By providing a measure of risk choice-and not only a net score-we show that adolescents with ADHD also fail to avoid risk choices. This deficit is mainly because they are slower in learning how to avoid risk choices, and not simply deficient. Literature is scarce concerning studies with Iowa-type paradigms in samples intregated exclusively by adolescents. More research is needed to clarify the nature of these deficiencies.

Desarrollo de funciones ejecutivas, de la niñez a la juventud / Executive functions development, from childhood to youthhood

Las funciones ejecutivas se encuentran entre los procesos más complejos del humano; su desarrollo permite la conformación de diversas capacidades de control, y organización de la conducta y la cognición. En este artículo se presenta una extensa revisión de la literatura más relevante a nivel internacional sobre el tema. Se abarca el proceso de desarrollo desde la niñez hasta la juventud, analizando las características de desarrollo de las principales funciones ejecutivas. Se muestra que la hipótesis planteada por Victoria Anderson hace ya una década es correcta: las funciones ejecutivas se desarrollan de forma secuencial y curvilínea: un intenso progreso en la infancia, con una desaceleración a inicios de la adolescencia. También se analiza el efecto de otros factores adicionales a la edad como son el efecto de la escolaridad, los estilos parentales y el contexto cultural

The executive functions are among the most complex cognitive processes in the human; during development they support the conformation of several capacities for organization and control of behavior and cognition. In this article an extensive review on the most relevant scientific literature is presented, with a developmental range from childhood to youth hood. An analysis on the developmental characteristics of the main executive functions is offered. The review indicates that the hypothesis stated by Victoria Anderson a decade ago, is accurate: the executive functions develops in a sequential form, with a curvilinear behavior: an intense progression during childhood, with slowness by early adolescence. Effects of additional factors like school level, parenting, and cultural context are also analyzed