You can have certain traits, yet never have the diagnosis, regardless of what that diagnosis is.
Sometimes I worry that in societies desire for conformity we are too quick to tag a disorder to what may just be personality quirks that make us individuals. If the person can't function, ok....fine. If they are functioning just fine, diagnosis or traits or personality quirks......in my opinion leave it alone.
I was diagnosed severely ADHD as a child (I'm 49, they were correct by the way). No medications. No IEP. No nothing. At home I was kept busy with chores and physical play, expected to tow the line from a no nonsense mother who could care less about dxes or no dxes. Know what I mean?? At school I was expected to follow rules and do what everyone else did. Ok. I had my quirks.......as I've grown older I've realized they are a lot more than I used to think too. I had things I flat out refused to do....such as homework and working in a group. In my mind I have valid reasons and trust me, no one was ever able to change my mind......I am still this way. I can work in a group but I don't care at all for it. Yet I passed each grade just fine.......actually with pretty good grades, by high school I was honor roll and could've easily graduated at 16, they just neglected to inform me of this fact. I wasn't a trouble maker.......I had a mother to answer to and I was more scared of her than anyone else on the planet. lol
In short, I learned to cope with being extremely active (which by the way is what ADHD truly means). I burned off energy when I had the chance and learned to sit still otherwise.
Now there are some dxes such an approach would not work......and it would depend on the home environment and the personality of the child as well.
I just worry that these days professionals are too quick to label (after all it keeps the money flowing, stop to think about that) too quick to treat with medications ect, and I've met only a few willing to take the time to try to get a clear detailed picture of the child. Schools / society want the children to conform. Parents want what they are taught is best for their children........by.....society.
Granddaughter Aubrey is very active as well. May/may not have ADHD. Doesn't matter as Nichole refuses to take her to a professional (which I back her up in this). Aubrey is encouraged play / chores that burn off energy and is being taught to cope/enjoy sitting still and learning. She's also exceptionally bright........and gets bored easily due to that. She is her grandma's granddaughter........truly........and her mother's daughter. She is opinionated, will speak her mind, and will dig in her heels over something she believes strongly. School doesn't like these traits. Too bad. I've found them to serve both me and Nichole well in life.......we encourage them in our family. lol
Often though, it is just how you choose to look at something.
As IC said, I believe most professionals view conduct disorder as an acquired via experience/environment disorder. So, do you and grandchild have certain personality quirks in common, or is it possible certain ineffective parenting techniques were passed down through the generations? (this is what I mean about docs really needing to try to learn as much about the whole picture when it comes to a child)
If you've done just fine without a diagnosis until age 49, I wouldn't bother looking for that diagnosis.