Serum Tau and α-Synuclein in Children With Attention-Deficit/Hyperactivity Disorder: Cross-Sectional Associations With Methylphenidate Treatment.

OBJECTIVE

To compare serum total tau and α-synuclein among controls, drug-naïve children with attention-deficit/hyperactivity disorder (ADHD) and children with ADHD receiving methylphenidate.

METHODS

Original ELISA spreadsheets provided 26 controls, 29 evaluable drug-naïve participants and 32 methylphenidate-treated participants. Boundary-coded results (> 500 pg/mL for tau; < 938 pg/mL for α-synuclein) were assigned the recorded boundary for rank-based analyses. Groups were compared using Kruskal-Wallis tests and Dunn-Bonferroni contrasts; within-group associations used Spearman correlations.

RESULTS

α-Synuclein differed among groups (H = 49.859, p < 0.001, ε2 = 0.570), with all pairwise contrasts significant. Tau also differed (H = 10.492, p = 0.005, ε2 = 0.101); drug-naïve ADHD had lower tau than controls, whereas the treated group differed from neither comparator after correction. The α-synuclein-tau correlation remained significant after false-discovery-rate adjustment only in drug-naïve ADHD (ρ = 0.443, adjusted p = 0.048).

CONCLUSIONS

Serum α-synuclein and total tau showed distinct cross-sectional group patterns. These associations do not establish methylphenidate effects and require prospective confirmation.