Longitudinal MRI studies of children with attention-deficit/hyperactivity disorder: A systematic review.

In 30 seconds

This systematic review examined longitudinal MRI studies of brain development in children with ADHD, covering 32 studies selected from 3385 screened papers and participants aged 4–18 years at baseline. Compared with typically developing children, children with ADHD generally showed smaller brain volumes and delayed cortical development, although differences in volume and cortical thickness often diminished with age. A meta-analysis of longitudinal change in total gray matter volume found no significant difference between groups. The authors emphasize that inconsistent findings and methodological challenges warrant cautious interpretation.

Key findings

• Across reviewed studies, children with ADHD showed smaller cerebral and cerebellar volumes, without significant differences in their developmental trajectories.
• Delayed peaks in cortical thickness, surface area, and gyrification were reported in prefrontal, temporal, and occipital regions.
• Differences in brain volume and cortical thickness often diminished with age, particularly in cerebellar white matter and the caudate.
• Meta-analysis found no significant difference in longitudinal total gray matter volume change between children with ADHD and typically developing peers.

Why it matters

Longitudinal imaging findings suggest that brain-development differences associated with childhood ADHD may vary by region and developmental stage rather than follow a uniform pattern. The absence of a significant group difference in total gray matter change, alongside reported regional differences, underscores the importance of interpreting MRI findings in context and avoiding conclusions based on a single measure.

What to keep in mind

The review reports inconsistencies across studies and methodological challenges in integrating findings; selection bias is also a concern.