ESPE Abstracts

Background/aim: Limited studies have delved into the association between thyroid hormones and neurocognition in attention-deficit/hyperactivity disorder (ADHD). We aimed to evaluate the relationship between thyroid hormone levels and neurocognitive functions in patients with ADHD.

Method: A total of 146 patients with early-onset ADHD were included in the study. The inclusion criteria for patients with early-onset ADHD were age 5–12 years, ADHD >1 year, normotonic status, body mass index (BMI) less than the age- and sex-specific 95th percentile, absence of chronic diseases. None of the patients with ADHD took any medication. The participants underwent a cognitive assessment including inattention and hyperactivity/impulsivity scores. Blood samples were collected to measure serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3). Subgroup analyses were conducted based on the severity of inattention and hyperactivity/impulsivity symptoms.

Findings: The results revealed a significant association between fT4 levels and various inattention, aesthetics and interactivity scores. However, serum TSH and fT3 levels exhibited no significant association with inattention, aesthetics and interactivity scores in adjusted linear regression models. Specifically, the correlation between fT4 levels and aesthetics and interactivity scores was more pronounced in patients with higher scores.

Conclusion: Serum fT3 levels were associated with the performance across various cognitive domains in cases of ADHD. This correlation was accentuated among patients with higher illness severity. Future studies could focus on the effects of specific pathways that can affect the course and progression of ADHD associated with serious functional impairment, in various domains, leading to academic, social, vocational, and familial consequences.