The important part is "doesn't seem to have the ability to stop." ABA is behavioral, and if a child can't stop, then he will fail, which is bad for his self-esteem. I'd recommend checking with the people on the FB group Autism Inclusivity--it's autistic adults helping parents of autistic kids. They might have some suggestions of what worked for them as children.

Try Ross Greene's The Explosive Child. It takes a skills-building approach instead of a punishment approach.

What helps us is talking about events after the event- when she is ready to talk and understand. During the event- give space, agree with whatever and get her to calm down as soon as possible. We don’t deal with self harm- early on I told her I love her too much to watch her hurt herself. I don’t let anyone hurt you, you don’t get to hurt yourself. We had behaviors but they are non existent right now, other than screaming- even that she has and is getting better at. I tell her if she screams I don’t understand her or have a hard time understanding her. Still if she wants to scream it’s her choice. We don’t do rewards or punishment. Hope that helps.

We have learned with our little one that grabbing him and holding him tight works also when we scold him it tends to be worse so we give him the soft caring voice pull him in hold him and talk to him about why or why not he can continue that type of behavior. Our little guy is 3 and doesn’t understand everything but does understand most and seems to be getting pretty verbal. Hope this helps also look into weight blankets. God bless our little angels

We used ABA therapy, behavior contracts and medication.