ADHD Endophenotypes in Caribbean Families.

Objective: The aim of this study is to contrast the genetics of neuropsychological tasks in individuals from nuclear families clustering ADHD in a Caribbean community. Method: We recruited and clinically characterized 408 individuals using an extensive battery of neuropsychological tasks. The genetic variance underpinning these tasks was estimated by heritability. A predictive framework for ADHD diagnosis was derived using these tasks. Results: We found that individuals with ADHD differed from controls in tasks of mental control, visuospatial ability, visuoverbal memory, phonological and verbal fluency, verbal and semantic fluency, cognitive flexibility, and cognitive ability. Among them, tasks of mental control, visuoverbal memory, phonological fluency, semantic verbal fluency, and intelligence had a significant heritability. A predictive model of ADHD diagnosis using these endophenotypes yields remarkable classification rate, sensitivity, specificity, and precision values (above 80%). Conclusion: We have dissected new cognitive endophenotypes in ADHD that can be suitable to assess the neurobiological and genetic basis of ADHD.

[Behavioural and neuropsychological characteristics of children of both sexes, between 6 and 11 years of age, with attention deficit hyperactivity disorder]. / Características conductuales y neuropsicológicas de niños de ambos sexos, de 6 a 11 años, con trastorno por déficit de atención/hiperactividad.

INTRODUCTION: Attention deficit hyperactivity disorder (ADHD) gives rise to behavioural and neuropsychological alterations. AIMS: The purpose of this study is to compare the behavioural and neuropsychological skills of 6 to 11-year-old children of both sexes, who have been diagnosed with ADHD, with that of a control group. SUBJECTS AND METHODS: From a total of 1200 schoolchildren, whose parents and teachers answered a brief ADHD screening survey, we selected 112 participants who were then submitted to a psychological clinical interview and a neurological examination in order to assign them to one of three groups: combined-type ADHD, inattentive ADHD and a control group. Behaviour was assessed by applying the Conners' Rating Scales and the multidimensional behaviour survey. Cognitive capacities were assessed by applying a neuropsychological battery for attention, memory, visuomotor and verbal skills, and executive functions. Groups were compared by means of a Kruskal-Wallis non-parametric univariate analysis of variance. In the case of pairs of groups, the Mann-Whitney U test was employed. RESULTS: The behavioural scales showed greater alterations in the case groups, with more problems in the combined-type ADHD group. Neuropsychologically, significantly lower performances were observed in the ADHD groups in sustained attention, executive function, semantic and phonological fluency tests. CONCLUSIONS: Behavioural disorders are the most apparent in ADHD. The neuropsychological alterations that were found were similar to those reported in other studies conducted in Colombia.