Examining epigenetic aging in the post-mortem brain in attention deficit hyperactivity disorder

Area of Science:

• Neuroscience
• Genetics
• Psychiatry

Background:

• Epigenetic clocks estimate biological age using DNA methylation.
• Previous studies show altered epigenetic aging in other neurodevelopmental disorders.
• Attention-Deficit/Hyperactivity Disorder (ADHD) is a prevalent neurodevelopmental condition lacking epigenetic aging studies.

Purpose of the Study:

• To investigate epigenetic aging in post-mortem brain and peripheral tissues of individuals with ADHD.
• To determine if ADHD is associated with accelerated or delayed biological aging.
• To identify the best-performing epigenetic clocks for different human tissues.

Main Methods:

• Applied four epigenetic clocks to DNA methylation data from ADHD and control groups.
• Analyzed cortical (anterior cingulate cortex) and striatal (caudate) brain tissue, blood, and saliva.
• Assessed associations between ADHD diagnosis and epigenetic age, controlling for covariates.

Main Results:

• Epigenetic clocks accurately predicted chronological age across all analyzed tissues.
• No significant association was found between ADHD diagnosis and altered epigenetic aging in brain or peripheral tissues.
• Findings remained consistent after accounting for comorbidities and medication use.

Conclusions:

• This study provides no evidence for altered epigenetic aging in ADHD.
• Potential reasons for null findings include tissue/region specificity, age range, and counteracting developmental processes.
• Further research is needed to explore the complex relationship between ADHD, brain development, and epigenetic modifications.