You asked, " How do you have consequences for someone who only lives in the here and now?"
Short answer - you can't. And shouldn't. Why punish a child for something he can't control? It's like trying to nail down the end of the rainbow.
Prevention is best, and then come natural consequences. ADHD kids are not naughty on purpose. If you sat them down to give them a written test on what is acceptable behaviour and what isn't, they'd probably score well. The problem is, when it comes to USING these rules, they have to have the skills to be able to stop and think first. And they just haven't got those skills. To punish them for this is just plain cruel and will be teaching them that they are being punished for who and what they are. They are automatically set up for failure. You get upset, they get upset, you have to waste your time imposing discipline and supervising it and also dealing with the fallout of their resentment (which often produces more behaviour requiring punishment).
Stop the cycle. Deal with prevention where possible, let them see natural consequences and reparation rather than punishment. Respect their efforts even when those efforts fail, and you will have more success in requesting that same respect in return.
There will be times they will shout at you in frustration (well, you do that to them sometimes, we all do) and times they will throw things. They will do stupid things out of impulsiveness. But the consequences will happen anyway.
Example from a few minutes ago - difficult child 3 has been breaking curfew for the last few nights, playing on his Nintendo DS after bedtime. So for the last two nights, husband has confiscated it. difficult child 3 was very angry about it last night. But tonight he was calm. It's bedtime for him now. I just asked him to bring me his Nintendo DS. "But I'm not going to play it, I'm going straight to sleep."
I told him, "You've said that before, and you've been found playing games after you should have games off. So I'm keeping this for tonight so you won't be tempted."
"But I won't play it!"
"Then it won't matter if I leave it on this desk - you can get it first thing in the morning and play it then, you don't have to wait until I give it to you. But this is a consequence of you breaking the rules for the past two nights - we're helping you keep those rules."
He's now gone to bed, without his DS but also without a fight. He knows he has to earn our trust again. But he's a fast learner - I will let him have it back for tomorrow night, but we will check to make sure he's not breaking rules again. And he knows this.
He's still impulsive. He often makes mistakes, gets loudly angry, can sound very rude. But if we react with punishment all the time he would be even worse because his anxiety and stress would make all these problems MORE likely. By helping him learn self-control and mood control he is more able to behave as he knows is proper.
Inside every difficult child is a really good kid who wants to be able to be easy child but just can't find the way. So they behave in other ways which we don't like. It gets worse. They're trapped in a large black box with no light in it and can't find the door. If we keep zapping them for failing to find the door they'll be even more frightened and scared, making it harder for them to think their way out.
I'm a Ross Greene fan. It works to different degrees in different situations, but it's always worth a read. It's been brilliant, for us. And I'm a much happier person, not having to punish.
Marg