Endocrine Abstracts

JOINT721

Background: Methylphenidate (known as Ritalin) is widely used for treating attention deficit disorder (ADD) and Attention Deficit Hyperactivity Disorder (ADHD) in children. Long-term treatment has raised concerns regarding its impact on growth, thyroid function, and cortisol secretion. This review aimed to summarize findings from studies between 2000 and 2024 that investigated the effects of methylphenidate on these parameters.

Methods: A comprehensive literature review identified 20 studies examining the effects of methylphenidate on growth parameters (height, weight, IGF-1), thyroid hormones (FT4, TSH), and adrenal function (cortisol, DHEA-S). A total of 3, 500 children and adolescents across various studies were included, ranging in age from 3 to 18.

Results: • Growth: Twelve studies reported significant reductions in height and weight gain, particularly in the first 6–12 months of treatment. Reductions in height Z-scores were observed, with mild growth suppression attributed to appetite suppression and metabolic changes. Some studies (e. g., Safer et al., 1979) noted rebound growth after treatment discontinuation.

• IGF-1: Inconsistent findings were reported. While 5 studies (Harstad et al., 2022, among others) found no significant change in IGF-1 levels, others observed mild decreases correlating with reduced growth velocity.

• Thyroid: Data from 3 studies indicated that methylphenidate has no significant impact on thyroid function (FT4, TSH). Harstad et al. (2022) confirmed no association between methylphenidate and thyroid dysfunction.

• Cortisol: Findings were mixed across 6 studies. Kholif et al. (2021) reported increased salivary cortisol levels after one month, indicating HPA axis activation. However, studies by Lee et al. (2008) and Pitzianti et al. (2020) found no significant changes in cortisol levels, while some reported elevated DHEA-S without clinical significance.

Conclusion: This review, encompassing 20 studies with 3, 500 children, highlights mild growth suppression associated with methylphenidate, especially early in treatment. Thyroid function appears unaffected, while cortisol secretion results remain inconsistent, suggesting variable HPA axis effects. Regular monitoring of growth, IGF-1, and adrenal function is recommended for children on long-term methylphenidate therapy to detect and address potential endocrine disturbances.