Straterra is an anti-depressant type of medication. They use it for adhd and to stabilize behaviors/moods with children and adults. Though its rate of success isn't as high in children as adults it does work with some. Your son is too young for them to classify him as bi-polar, but ODD with the mood swings sounds more like that is the diagnosis you might be looking at, I am not a doctor, but you may want to ask. Good luck. Stratterra is something I have been pushing for my daughter, but they don't feel it is quite right for her.
Hope you find your answer.
My 8 year old stepson has been on strattera for ADHD for 7 weeks now. 25mg a day. there have been no side affects except a little tired in the begining few weeks. obviously everyone can react different but my son has had no problems with it. I do watch him closely just in case any arise. I also like that it is a non-stimulant compared to everything else out there.