I think these research studies could provide more insight into your question. [https://www.medicalnewstoday.com/articles/adhd-stuttering](https://www.medicalnewstoday.com/articles/adhd-stuttering) *"Those with more severe ADHD symptoms may have more persistent or severe stuttering"* [Research](https://www.sciencedirect.com/science/article/pii/S0094730X24000494): Adult stuttering prevalence I: Systematic review and identification of stuttering in large populations (2025) *"Studies of pharmacogenic stuttering were based on pharmacovigilance data, with suggestion that alteration of dopamine levels might be an underlying mechanism. The ROR of 7.3 for stuttering with methylphenidate is notable due to frequent methylphenidate prescription for ADHD in children older than 6 years. ADHD has been identified as a diagnosis co-occurring with stuttering at rates higher than chance (Blood, Ridenour, Qualls & Hammer, 2003; Dönmez & Özcan, 2020; Tichenor, Johnson & Yaruss, 2021). Such co-occurrence may3 be a contraindication for prescribing methylphenidate as an ADHD treatment for children diagnosed as stuttering. In cases where the onset of childhood stuttering follows prescription of methylphenidate to treat ADHD, causation may be pharmacogenenic rather than neurodevelopmental and appropriate treatment may involve change of medication instead of, or as well as, speech and language therapy."*