[Concordances between autism spectrum disorders and attention deficit hyperactivity disorder]

Area of Science:

• Neuroscience
• Genetics
• Developmental Psychology

Background:

• Growing evidence highlights shared genetic, clinical, and neuropsychological features between autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).
• These overlaps suggest a potential common underlying pattern in etiology and symptom presentation for both neurodevelopmental disorders.

Purpose of the Study:

• To review current research on the common aspects and shared neurodevelopmental basis of ASD and ADHD.
• To explore the implications of this shared understanding for clinical practice and treatment decisions.

Main Methods:

• Literature review of studies examining genetic, structural, functional, and behavioral overlaps between ASD and ADHD.
• Analysis of research on preschool attentional difficulties, genetic factor overlap (50-72%), and shared neuroanatomical alterations (e.g., corpus callosum volume).
• Examination of functional brain alterations (hypoactivation in specific regions) and executive functioning profiles.

Main Results:

• Preschool attentional difficulties are identified as a potential early indicator for both ASD and ADHD.
• Significant genetic overlap (50-72%) and shared neuroanatomical differences (reduced corpus callosum and left frontal grey matter volume) are observed.
• Functional brain alterations and distinct executive functioning profiles are associated with both conditions, with links between early ASD behaviors and later hyperactivity.

Conclusions:

• A new conceptualization of an ASD-ADHD continuum with a common neurodevelopmental basis is proposed.
• This understanding can significantly aid clinical practice by informing diagnostic and treatment approaches.
• Considering the association between ASD and ADHD is recommended when planning interventions.