I think it is important to remember that, "Children with ADHD have a legitimate neurological condition that impairs planning, organization, impulse control, focus, and attention. ADHD cannot be cured, but it can be managed with teaching strategies, accommodations, practicing difficult skills, and, sometimes, medication.
Sometimes parents think that their children should be able to follow through on cleaning their room, finish a whole worksheet without being distracted, remember their notebooks, and keep their hands to themselves when reminded. However, these expectations may be unrealistic without interventions and accommodations."
Essentially, you don't fix things through punishment. You do so through behavioral change. And, even in 6th grade, if you are punishing him for things he is doing at school. You may be punishing him for things he doesn't have much control over. Or you may be punishing him for things that the school is doing wrong in working with him. In short, the school needs to be much more highly involved then you are. Does he have a 504 plan or an IEP? These things are essential.
Also is he in 6th grade. Has he gone from a elementary school to a middle school? That is a huge change for a child. I taught both 5th and 6th grade for years. I saw plenty of kids in 6th grade just fall apart at the start of the school year. And, a lot of that, was due to lack of communication between all involved.
Here is a good link with a lot of info for ways for schools to help kids.
http://www.additudemag.com/resource-center/adhd-school-behavior.html
And this is a very good link on the correct ways to discipline/change behavior at home.
http://www.additudemag.com/adhdblogs/31/10784.html
In a nutshell, the school needs to devise ways to help him/accommodate him. If this year at school is going different then last year, then its a good chance that the new situation is part of the problem. You need to help him - not punish him.
You also should find out from his teachers what is exactly going on and when it is going on. Is he having more problems in the afternoon then the morning? Is he having more problems with a particular teacher/subject then the others. It may be that a medication change may also be needed, so also let his psyc know what is going on. And hopefully, you can find a psyc that you can work with. It really sounds like you have not been getting the help that you should be getting!
I hope this is enough to help you get started without over whelming you. there really is a lot that can be done. Let me know if you need more info. Best wishes.
Oh, I'm really sorry to hear this. I have a son in 5th grade, age 10 and I know how hard social problems can be. When did he start having trouble with his peers? Was it early on and now he has low self esteem? I'm just wondering how much is peer interaction issues play into this. I've noticed that when kids feel like they are being ignored, overlooked or looked down on by peers, they often act out. ANY attention is better than no attention.
I would honestly try to help him with his peer interaction as a first step and his self esteem as well. Does he have any outside of school activities? Often kids like this don't and it's important to get them involved. What about band? Does he do any sports? What about Destination Imagination? Does he like acting, doing school plays?
I know that the poor peer interaction can come from the issues you describe or is the poor interaction the cause of the bad behavior?
does your school have any social programs? Friends programs?