April 20, 2024
Genetic Link Between Early Vocabulary and ADHD, Literacy, and Cognition Explored

Genetic Link Between Early Vocabulary and ADHD, Literacy, and Cognition Explored

Research has highlighted the significance of early language development as a predictive factor for a child’s future language, reading, and learning capabilities. Language learning difficulties have been associated with neurodevelopmental conditions like attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Typically, children utter their initial words between 10 to 15 months, expanding to 100–600 words by age two, with a much larger understanding of vocabulary. Beate St Pourcain, a senior researcher leading the study, explains that genetic coding contributes to the individual differences in language development.

In a genome-wide meta-analysis study, researchers examined vocabulary size in infants (15–18 months) and toddlers (24–38 months) to comprehend genetics’ impact on word production and comprehension in children. Utilizing data from 17,298 children speaking English, Danish, or Dutch, the team collected vocabulary and genetic information. The study linked early vocabulary size to later outcomes like literacy skills, general cognition, and neurodevelopmental conditions such as ADHD and ASD.

The study identified genetic factors influencing vocabulary size during infancy and toddlerhood, with varying associations to literacy, cognition, and ADHD-related traits. While infant word production showed links to literacy skills like spelling, cognitive associations were more prevalent in toddlers. Toddlers, who have developed language fluency, engage in more structured learning through speech, requiring higher cognitive functions.

Interestingly, the research revealed a genetic association between increased spoken words in infancy and a higher risk of ADHD, which contrasted with a smaller vocabulary size in toddlers being linked to more ADHD symptoms. This suggests that genetic predispositions may impact early speaking behaviors differently than later stages of language development.

St Pourcain notes that genetic influences on vocabulary size change rapidly in the first two years of a child’s life, offering insights into early speech and language-related processes in health and disorder. Ellen Verhoef, the first author of the study, stresses the importance of assessing vocabulary size in infancy and toddlerhood for understanding future behavioral and cognitive outcomes, advocating for increased data collection efforts during these crucial developmental stages.

1. Source: Coherent Market Insights, Public sources, Desk research
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