I know it wasn't an attack on me, and honestly, you didn't have to apologise, but I do appreciate the kind response.
The point is, my ADHD comes with RSD, which means I take things far too personally sometimes. I can't help the natural reaction - my brain works that way. My go to response is 'everyone hates me, everyone thinks I'm stupid', and it's not usually the case. The fact that you didn't mean to upset me didn't stop me from feeling upset.
Now that I know I have ADHD, I can take steps to rationalise that. I can remove myself from a situation that is making me feel that way - like I did the other day by closing down the thread and getting on with my day. I have those kind of coping strategies. I can let go of the negative feeling, distract myself, and make sure I have enough distance and time to process before coming back.
As a teen, I had no idea why I felt like that. I had no explanation. I was a really angry, emotionally turbulent teen - obviously, being female was blamed for it. It's the go to explanation. She's just moody because she's on her period. Actually, I just had difficulty regulating and making sense of my emotions because of the way my brain is wired. I think if I'd known I'd had ADHD, and had coaching to understand and accept why I was the way I was, I'd have a been a lot nicer to my mum.
People with ADHD and without ADHD are both just people. All people are capable of good and bad - all children are capable of being well-behaved and naughty. But when it comes to things like task initiation, executive dysfunction and emotional dysregulation, I think teens with ADHD deserve to be a cut a break.
ADHD coaching and medication are wonderful things, and I think it's terribly unfair to judge someone with ADHD who hasn't experienced those against someone who is NT. I look back on all the things I was told off for as a child with regret - rarely was I actually being naughty. Most of the time, I just couldn't do the thing I was supposed to do, and I couldn't manage the way I felt about that.
My ADHD lets me do some really brilliant, really clever things, and that's why I have a high flying job. But it genuinely makes it hard for me to look after myself and my environment, which is why I outsource that (thankfully I earn enough to pay for that). It's one of many masking tools I have in place as an adult - paying for a cleaner means everyone thinks I'm organised and tidy. Or maybe I'm just some rich bitch outsourcing the tasks she doesn't want to do. Either way, they don't know I have ADHD, because I'm a pro at hiding it.
A teen girl with ADHD isn't going to be able to follow the same strategy of paying for a cleaner. She isn't going to benefit from being shouted at to clean more. But if the OP helped break down something as overwhelming as cleaning her room in a oner to doing one distinct tiny task in 15 minutes, that could help her start. You can't treat ND and NT kids the same - all that does is frustrate and upset them and you.
Medication isn't for everyone, but coaching makes the world of difference. It's available for people with ADHD and for people whose loved ones have ADHD. You have to remember that ADHD is generally treated as a disability due to the impact it has on your day to day life.
So many posters have interpreted this situation as a mum rightly yelling at her kid for being a lazy little shit. It's actually a mum yelling at her child for not being able to do something that her disability makes a million times harder to do. It's not impossible for the child, but it's difficult - and it could be a lot easier if the mum tried to understand her point of view and tried to help her come up with strategies for her specific disability.
There will be things your grandchild is absolutely brilliant at because of their ADHD. There will be things they suck at. I really hope that you recognise that, and help them accept that it's okay to have different strengths and weaknesses to most of their peer group, and give them creative ideas of how to approach the things that don't come naturally, rather than berate and judge them like the OP has been doing to her child.