Since ADD hadn't really been defined when my children were growing up, I had only a cursory knowledge of it.
Just recently, it has been brought to my attention that people don't grow out of ADD, and that lots of dysfunctional people may be adults with ADD.
I began to study the traits of adults with ADD, and I find that one of my daughters, who is a drug addict, certainly fits the description. She is very bright, MENSA level, and sometimes speaks so rapidly you can't understand her. She recently took a college entrance exam, scored the highest grade ever, in the shortest time ever. When I mentioned the self medication theory to her, she said yes, when she smoked crack, her thoughts got clearer.
It's amazing that it has taken us this long to discover this. Now she is reading the material on adult symptoms, medication and ways to deal with the problem.
I am happy to share this in case it might help someone else.