Fig. 2.

Brain iron indices increased with age in controls but increased with medication duration in individuals with ADHD.

A. In the control group (green), magnetic field correlation (MFC) indices of brain iron significantly increased with age in the globus pallidus (GP), putamen (PUT), caudate nucleus (CN), thalamus (THL) and red nucleus (RN); Conversely, in the ADHD group, MFC significantly increased with psychostimulant medication (Rx) duration when controlling for age in the GP, PUT and THL (blue). This correlation was not observed with age when controlling for Rx duration (red). B. Similar results were found with R2* relaxation rate indices of brain iron. r: Pearson's correlation, r_s: Spearman's correlation (ranked values plotted), §: partial correlations (residual values plotted). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)