Punishments don’t work for ADHD because the effects don’t last. Punishment is intended to help a child think through the consequence of an action before doing it again. Impulsivity overrides that ability to think things through before acting every time. So it doesn’t stick.
What will work is determining why she’s “being mean” and address that. It could be that she doesn’t realize she comes across mean. It could be that she has poor frustration tolerance or lagging emotional regulation skills. Or many other things… But, you can’t change the behavior without determining what drives it.
I would also challenge you to change the language you use to describe her behavior. Try to steer clear of words like mean, disrespectful, rude, etc. These give a sense of the behavior being a character issue, when it’s not. It’s a little thing, but it shifts your mindset which helps a great deal.
It sounds like this is an issue of working on emotional regulation and social skills. You can do this on your own or with the help of a therapist.
ADDitude Community Moderator, Parenting ADHD Trainer & Author, Mom to teen w/ ADHD, LDs, and autism