Parents of Children with ADHD Support Group
This community is designed as an open forum where the parents and guardians of children with ADHD (Attention-deficit/hyperactivity disorder) can give and receive support, as well as discuss ideas, techniques, concerns, surprises, and challenges they may face with their children.

I think they're good in conjunction with other help (or maybe if your son won't do anything else it's an option), but I found that the OT was so focused on physical reasons and problems that she missed the bigger picture - example: In preschool an OT came to observe my daughter and watched her stumble a few times. She indicated in her report that my daughter had a lack of development in her large muscles that contributed to this problem and recommended therapy. Since my daughter really wasn't normally klutzy, I looked at other options and found that in truth the shoes my daughter was wearing were clumsy and caused her to trip and stumble. When she stopped wearing them, she never tripped again. The OT was so focused on this perceived problem (because that was her job) that I feel we missed a true diagnosis for longer until we engaged a behavioral therapist.
Everyone's experience is different - that's just mine, and perhaps more OTs branch into other areas of therapy more.
If, like my daughter the anger/frustration is caused by the way other people act/things they do, it will be less so.
I think there's a combination in most of our kids. The OT helps my daughter with things like sitting in her seat and how to calm herself once she's upset - large movements, available tools within the school etc, - but that works because the OT is on-site. obviously it's not going to help if I have to set up an appointment and wait a week. :-)
It may be worth just talking to the OT on the phone to see what kinds of things they might be able to do. Then you could decide if it's worth it or not. Good luck!!