The genetics of attention deficit hyperactivity disorder

Area of Science:

• Genetics
• Neuroscience
• Developmental Psychology

Background:

• Childhood Attention Deficit Hyperactivity Disorder (ADHD) has substantial genetic influences, with heritability estimates from twin studies ranging from 60% to 90%.
• Environmental influences are primarily non-shared, ranging from 10% to 40%, with minimal shared environmental impact.
• Quantitative genetic findings have spurred molecular genetic research into ADHD candidate genes over the past decade.

Purpose of the Study:

• To review recent findings from molecular genetic association and linkage studies of childhood ADHD.
• To identify candidate genes with the most replicable associations, suggesting a promising etiological role.
• To discuss emerging themes for future ADHD genetics research.

Main Methods:

• Review of published molecular genetic studies (association and linkage) focusing on candidate genes in childhood ADHD.
• Analysis of findings related to neurotransmitter systems (dopamine, norepinephrine, serotonin) and other genes involved in neural development.
• Identification of candidate genes with consistent and replicable association results.

Main Results:

• Substantial genetic heritability for ADHD confirmed by twin studies.
• Molecular genetic studies have investigated numerous candidate genes, particularly those in neurotransmitter pathways.
• Certain candidate genes show more consistent associations, indicating potential etiological relevance.

Conclusions:

• Genetic factors are primary drivers of ADHD etiology.
• Replicable associations in candidate gene studies are crucial for advancing understanding.
• Future research should focus on emerging themes to further elucidate the genetic underpinnings of ADHD.