What medication is he on? When does he get aggressive? What are his triggers? Has he also been evaluated for ADHD or Sensory Processing Disorder as these can be common co-disorders and have different treatments.
and ya, this is very difficult for you. I feel for you. You should be getting more information on dealing with autistic kids. There are very specific ways to deal with a child having a melt down and ways to prevent that.
Thank you for getting back to me as that information is helpful. I am also the CL on the ADHD forum, and am much more versed in ADHD information. I do wonder what specialty your doctor has? A psyc, psychologist, or pediatrician?
Risperdal is a drug that does take awhile to begin working. If he has not been on it very long, that may be why it is not helping much yet. Having said that, Risperdal is on my list of meds I do not like. In this case, if it is not working and it has been given a fair chance, I would slowly get him off and try some other things, with your docs permission of course.
My main concern is that Risperdal is not dealing with the problem, only masking it. It sounds like your son is in "defense mode" and is striking out at those around him. Here is a good link to defense mode (and a few other good autistic articles. https://www.aspergerexperts.com/defense-mode/
It is also very possible that your son's ADHD, is what is causing him to go into his defense mode. Anxiety and Depression are very common co-disorders of ADHD. I would really look at dealing medically with the ADHD and behaviorally with the striking out. Here is a good example of a way to do so. https://www.aspergerexperts.com/defense-mode/why-rewards-and-punishments-dont-work/
Is your doc experienced with ADHD? Do you need more info on ADHD and dealing with it?
Another thing that I think will help is a series of books aimed at your sons age group. They are meant to be read aloud at home (many times) and practiced. What they do (with your help) is to give a skill set to the child so that he has other ways to deal with his anger.
A good example is Hands are not for hitting - found here --https://www.amazon.com/Hands-Hitting-Ages-Best-Behavior/dp/1575420775
I also thing that "When I feel Angry" would be very helpful. https://www.amazon.com/When-Feel-Angry-Way-Books/dp/0807588970/ref=pd_sim_14_5?_encoding=UTF8&pd_rd_i=0807588970&pd_rd_r=KFQVB1EX3R7DVT8TA8PB&pd_rd_w=1LLVE&pd_rd_wg=NlXUm&refRID=KFQVB1EX3R7DVT8TA8PB&th=1
With both of these links, you can find other books that will help you work with him at home to change his actions.
In short, don't expect his current medication to help much. You and his school need to be up on how to work with Autistic/ADHD kids. Stopping his trigger points, dealing with his defense mode, showing him ways to cope are what will make a difference.
I hope this helps. Let me know if you need more info! Best wishes.