M.J.
We had to start medication with our son at three due to severe ADHD. He was a danger to others and us (to the point of drawing blood), and was kicked out of preschool. We tried working with a child psychologist and then a behavioral therapist first, and also took ADHD parenting classes. We exhausted it all before even considering medication at a young age, but he was completely out of control. There was no quality of life in our house and our son was only getting negative feedback because he was so unbalanced.
At three, we were extremely cautious with medication and so was Kaiser. We agonized over the decision, but were told our son's case was extreme and given that he was such a danger to others, it was recommended. We had to be reassured repeatedly we weren't just horrible at parenting. The psychiatrist put him on Tenex and Clonidine first, neither of which did anything. Those were considered the safest, mildest options, though, so we went with them.
At four, our son got to try real ADHD medication. Day one of Ritalin was a "Wow!" day. We got to see our real son. He had the same personality, same spunk, same everything, without the aggression, hyperactivity, impulsivity and lack of focus.
Medication completely transformed our son's world. He went from being labeled a "bad kid" in preschool and having one friend to fitting in in school and having a bunch of friends. People don't know he has ADHD when his medication is active. We still have very rough patches when his medication isn't active and that's where our ongoing work with the behavioral therapist helps (We also belong to CHADD and went to their annual conference, and read ADDitude to stay on top of the latest strategies). Our son is 10 now and still has severe ADHD-combined type, but he made honor roll throughout fourth grade this year. Without medication, our son wouldn't be functional in school, let alone earning top-notch grades.
Medication isn't a cure-all by any means, but it helps with this horrendous medical condition. I wouldn't wish ADHD on my worst enemy. I'm incredibly glad we made the leap of faith and gave medication a try. It's been a roller coaster keeping the medication on track, because as kids grow, it stops working and dosages and brands have to be switched. Still worth all of the agonizing to give our son a normal life.
ETA: Reading a previous post of yours makes me think your son has ADHD? If that's the case, feel free to PM me anytime. I've been at this seven years now.