Seeing as how your son is both hyperactive and has severe asthma, you might want to take a look at his diet. I didn't find out about my own food allergies until I was in my late 30s and had suffered years of mental illness and death-threatening respiratory allergies. After removing the offending foods from my diet, I slowly began to get better. It's stupid to have to suffer so badly for so many years over something so simple to control. This may not be what is causing your son's problems, but it is sure worth taking a look.