I am dealing with a lot of the things that your son is dealing with, so let me just tell you that sometimes, teachers can be (sorry if that is off-putting) stupid when it comes to identifying gifted people. Maybe he could have an SPD, but then again, I think that could be just an over-excitability. I know I'm not a professional psychologist (although I will enroll myslef in some online classes), I'm sure it might be a panic disorder, but it may be part of giftedness. I wasn't an under-achiever in school, but I was (and still am) a social activist who argued when someone said cruel things, and they (my old evil teachers) called me arguementative and non-conforming, which in turn was my giftedness showing. Giftedness is not a disability, and if this only shows up at school, it may be that your child was understimulated. I could be friends with him though. I'd get along with him well!