Neural Correlates of ADHD and Depression

Notes

ADHD and depression are distinct clinical conditions with overlapping yet unique brain abnormalities. ADHD is a neurodevelopmental disorder characterised by inattention and hyperactivity, while depression is a mood disorder marked by persistent low mood. Both involve alterations in prefrontal and limbic regions, but the patterns and implications differ significantly. Structural neuroimaging studies consistently show that individuals with ADHD have reduced volume and cortical thickness in the prefrontal cortex (PFC), a region critical for executive functions such as planning, inhibition, and attention. Additionally, abnormalities in the basal ganglia and cerebellum are frequently reported, affecting motor control and reward processing. Functional MRI studies reveal underactivation in fronto-striatal circuits during attention and inhibition tasks. Longitudinal research indicates delayed cortical maturation, particularly in the PFC, which may normalise partially by adulthood. In depression, the most robust findings involve the limbic system. The hippocampus, essential for memory and emotion regulation, often shows volume reduction, believed to result from chronic stress and glucocorti...