I have ADHD and a stutter, they could definitely be related, but I’ve been on adhd meds for almost a year now and if anything it’s made my stutter worse, but that’s really just a personal thing because for some people adhd medication can help their stuttering, but not in my case! So just be aware that it will probably not just go away because you treat you’re adhd! (Excuse my spelling I’m not a native English speaker)