Turkish Journal of Medical Sciences
Abstract
Background/aim: This study analyzes thyroid function parameters (free T₃, free T₄, TSH) in children with attention-deficit/hyperactivity disorder (ADHD), ADHD with specific learning disorder, and healthy controls, to determine whether subtle thyroid dysregulation contributes to the phenotypic heterogeneity of ADHD.
Materials and methods: This retrospective, cross-sectional study included 135 children aged 6–18 years: 62 diagnosed with ADHD (38 isolated ADHD and 24 ADHD+SLD) and 73 healthy controls. Demographic, anthropometric, and thyroid function data (free T₃, free T₄, TSH) were extracted from medical records. Group comparisons were conducted using independent samples t-tests, ANOVA, and ANCOVA adjusted for age, sex, and treatment status.
Results: Children with ADHD exhibited higher free T₃ (p = 0.003), lower free T₄ (p = 0.020), and higher TSH (p = 0.048) levels than the controls. Subclinical hypothyroidism, isolated T₃ elevation, and euthyroid Hashimoto thyroiditis were more prevalent in the ADHD group (p = 0.032). No significant thyroid parameter differences were observed between isolated ADHD and ADHD+SLD. The direction of these endocrine differences persisted after covariate adjustment, although only free T3 remained statistically significant, suggesting subtle hypothalamic-pituitary-thyroid axis dysregulation in ADHD independent of stimulant treatment.
Conclusion: Children with ADHD exhibit subtle alterations in thyroid function, characterized by higher T₃ and TSH and lower T₄ levels, which may reflect compensatory or metabolic imbalance rather than overt thyroid disease. These findings highlight the potential role of neuroendocrine modulation in the pathophysiology of ADHD.
Author ORCID Identifier
GÜL TRABZON: 0000-0002-9262-5678
SEDA SARI: 0000-0003-4793-0662
SERVET YÜCE: 0000-0002-5264-3038
ŞEYMA GÜLLÜ: 0000-0003-3596-2704
DOI
10.55730/1300-0144.6349
Keywords
ADHD, neuroendocrinology, specific learning disorder, T3, T4, thyroid function
First Page
1054
Last Page
1064
Publisher
The Scientific and Technological Research Council of Türkiye (TÜBİTAK)
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
TRABZON, G, SARI, S. A, YÜCE, S, & GÜLLÜ, Ş. D (2026). Thyroid function in children with attention-deficit/hyperactivity disorder and specific learning disorder: a retrospective comparative study. Turkish Journal of Medical Sciences 56 (4): 1054-1064. https://doi.org/10.55730/1300-0144.6349
