Connectomic disturbances in ADHD: A systematic review of MRI-based global and nodal topology

Emerging evidence indicates that the neuropathology of attention-deficit/hyperactivity disorder (ADHD) extends beyond localized anomalies, and graph theoretical approaches provide interpretable indices for characterizing network-level organization. However, reported alterations of topological measures in ADHD remain inconsistent across studies, making it difficult to determine their overall direction and magnitude through individual studies. Here, we conducted a systematic search and identified 31 eligible MRI datasets, including 14 structural network studies (459 ADHD individuals; 460 controls) and 17 functional network studies (975 ADHD individuals; 1287 controls). A random-effects meta-analysis was performed to examine global topological patterns, and nodal signatures were explored using coordinate-based neuroimaging meta-analysis. Individuals with ADHD demonstrated significantly reduced global efficiency (Hedge’s g = -0.31; p = .010) in structural networks, whereas functional networks did not display significant global alterations. No nodal findings survived multiple-comparison correction; however, exploratory analyses at an uncorrected threshold suggested centrality alterations in key regions, including the caudate (Z = -3.60) and putamen (Z = -3.11) in structural networks, and the caudate (Z = 3.50), orbitofrontal cortex (Z = -3.41), and precuneus (Z = -3.58) in functional networks. In conclusion, reduced structural global efficiency suggests compromised capacity for brain-wide information integration in ADHD. Exploratory nodal analyses suggest that abnormalities in ADHD may extend beyond global network organization to specific regional topological features.