My 5 year old has had trouble with aggressive behavior and I tried quite a few different approaches, including many of the above mentioned. Rewards, reminders, deep breathing, talking about feelings.... everything I could possibly think of to help him understand his behavior was unacceptable. We finally figured out that his behavior needed a different sensory outlet (deep breathing just wasn't cutting it), so we have him apply pressure either by squeezing a stress ball (shaped like a kid-friendly duck that is clipped to his belt loop) or pushing on a wall or other hard surface. I was amazed at how well this has worked for him. When I see him begin to get frustrated, I remind him to squeeze his "angry" duck or go push on the wall and try to "push it down". The sensory input from the pressure of squeezing and pushing helps calm him down and eliminate the frustration and urge to lash out in hitting. He is now to the point where he can better handle situations without using aggressive behavior or will self-correct by squeezing his duck. Good luck to you! I hope you have found some good ideas that will work for you :-)

Good to rule out attention seeking. :)
What else does he like besides video games? Perhaps you could tie a video game break in on Thursday for an hour to his behavior Monday - Wednesday, and video games for the afternoon Sunday on his behavior the rest of the week... don't hit, hurt, or destroy and be a positive person to get what you want out of life sort of thing?

Some sort of goal he can work toward, anyway, for self-control. After all, what do most people get out of self-control and avoiding lashing out in the moment? For most, it is social rewards. Sometimes, for an autistic, it needs to be something visible and concrete like a favorite activity.

Just a thought... hope it helps!

To be honest, could it be frustration? Can he communicate, or is something stressing him out? It's like unpicking a knot to figure out what triggers there are. Don't be afraid to actually think in depth about what it might be? Could it be for example that he has things he needs to do in a certain way?

With Autism, it's the patterns that make it happen. If he's struggling at school, or if there's someone causing him trouble then he might well act out in an environment that he finds safe.

My son is similar, I knew when he had a bad day from the get go, he'd storm in and slam his bedroom door. We have an agreement, he withholds nothing from me and I will stand by him through thick and thin and I think he's realised finally that I actually do a hell of a lot to make his life easier. It's hard though. The tantrums are so much easier to control when he kicks off. He does get anxious and he's learning how to recognise when he's feeling anxious.

I am almost helping him to write some new coding for his brain, giving him the help tools he needs to cope in the adult world.
Perhaps over stimulation during your son's day has been building up like a pressure cooker?

My son was lucky though, I myself put a team network of teachers in place for Toby (my son). I organised the meetings with the school, every one of his teachers was present, I liaise with his year tutor and the SENCO to make sure that he's got all the coping mechanisms in place. He's going through his exams right now, he's got a college place secured and he's going to France in the summer with a school trip to do water sports for a whole week. This is something he is desperate to do and as a hi functioning Aspie, it's a great challenge for him.

Toby is 16. He was diagnosed last year, and previously had had certain problems all through his school life. That he's survived the entire experience unscathed, unexpelled and without any suspensions, maybe five detentions, I think is a credit to himself and in part me.

So don't give up, sure get frustrated, but most of all - please don't feel alone.

Although this is easier said than done, our parent trainer says I should see if there is a pattern that causes the act (the hitting). If you know what causes the act you can be proactive and potentially stop it from happening. My 6year old daughter who is also impulsive tends to hit her brother when she's frustrated at anything. As soon as I hear any frustration I (calmly, most of the time) remove her to another room where is can open up a toolbox with sensory toys (such as playdoh, writing pad w/ crayons, and other fidgets). Sometimes I will use a printed out stop sign as a visual to help and have her do deep breathing. I set the timer for 10 minutes to play with it and she is better after that. I have even sat down with her and we've played with the playdoh together. I put the toolbox together based on what she likes (she's very tactile) but she decorated and made it her own - even picked out a special spot for it herself. Hope this helps.

Talk to Dr my son was aggressive till Dr put on medicine now not as bad but monitor careful make sure not to mediated for the child