Wanted to mention that a friend's son went on Ritalin for his ADD/ADHD and develped diabetes that requires insulin...they didn't discover the problem until he ended up in the hospital in a diabetic coma. They almost lost him.
My daughter has Sensory Processing Disorder (on the Autism spectrum). We suspected she had an issue when she was about two; we discovered her issue when she was five (saw a Childhood Specialist), and she is now eleven. We were adament about NOT putting her on any pharma drugs of any kind. Refuse to.
Instead, when she was seven years old I switched the entire family over to organic food. We had been tested and we discovered that, among us, we had gluten intolerance, soy intolerance, and casein allergy (with me having some other food intolerances). Just from getting off gluten and cow dairy, we noticed an almost overnight improvement in our daughter. By getting rid of/not eating foods with pesticides, herbicides, chemicals, or any factory-made foods that have preservatives, colorings or dyes, artificial flavorings, or anything else that isn't natural/organic (we eat grass-fed animal products), every one of us noticed a huge difference--not only did my daughter continue to drastically improve in how she behaved, but none of us got sick! This includes staying away from excitotoxins like MSG and other artificial sweeteners (the articifical ones, like Splenda and Aspartame and Nutrasweet; the natural sweetener Stevia (it comes from a plant) is fine to use; in fact, we use it all the time. We also use pure unrefined cane sugar.).
ADD/ADHA usually is because there is a chemical imbalance in the brain/body; once that imbalance is discovered and corrected, it's amazing how many symptoms simply go away...or improve dramatically. I would suggest finding a good Naturopathic Doctor who can help you, your son, and your family embrace a different way of looking at your son's diagnosis--as a wake up call to change your eating and lifestyle habits--and I think you'll be pleasantly surprised at how little you'll come to rely on allopathic doctors and/or pharma drugs (because your body will be healthy and won't need synthetic chemicals).
Also, it is highly likely that your son's body has a high level of heavy metal toxicity--both I and my daughter were tested, and my daughter was so much more toxic than me, it blew me away! (I mean, I am 32 years older than her; you'd think I would be more toxic in heavy metals than her, because I've lived longer. But it was exactly the other way around!) We both chelated, and that, again, has helped enormously with easing her symptoms (as well as my medical issues).
I can't believe any doctor, in good conscious, would want to put any child on a pharma drug that chemically alters their brain chemistry. The drugs have never been tested for use on children, and there is no way to know how the drugs will interact with a growing child's body/evolving brain.
My daughter has a boy friend in her class who went on pharma drugs to help his issues. My daughter came home from school almost every day, crying or complaining about how her friend was no longer nice to her, that all he did was talk about himself, that he wanted to drink water all the time, that he thought he was all important and wanted to be cool, that he would literally bounce on his feet and be all wired up--and then when he crashed, he was someone that no one wanted to be around. She no longer wants anything to do with him. He's not the same person he'd been before he went on the meds.
The meds physically change/alter the chemicals in the body/brain. If they do help with some of your son's issues, are you prepared for him to be a totally different person? Many children who go on meds become like zombies. Or they go the other extreme and they go high-low in their emotions. I have found it much easier to deal with my daughter by changing our diet and working with a Childhood Specialist in learning how to modify or work through any issues she has.
If you do any reading on the Autism Spectrum (and I'm giving you this area to explore, just because so much has been written about it), you'll see that many, many parents who have gone to an organic diet and cut out gluten and cow dairy from their childrens' diets have seen drastic improvements in their children--some of whom have even been "cured." (It's been thought that there are many, many people who have food allergies and/or intolerances and don't know it; food cannot only affect the body and make us ill; it can also affect our brain chemistry as well. Foods that the body has an issue with can seriously impact the body/brain and how they function.)
Having him checked for food allergies/intolerances is something I would seriously look into and investigate before thinking about putting your son on chemical pharma drugs. Investigate it, at least. A few parents I know who have children with other behavior issues (like ADD/ADHA) have seen some drastic changes/results in their own children from changing their diets--for the better.