Here is a link to wikipedia, look under "signs and symptoms". A person doesn't need to have all of the symptoms, but a certain number of them to be diagnosed and there are different types of ADHD. Some kids are mainly impulsive/hyper and others may be mainly inattentive. DS's pediatrician did a "provisional diagnosis" since he was borderline, to see if meds would help, The problem with this approach is that meds are usually started at a low dose and then gradually raised, and you are not going to know if it's just the low dose that doesn't work, or if it's really not ADHD. We did a trial of meds but even on the low doses DS wasn't eating and I didn't see that much of a difference, so we stopped. With DD who has a more severe case, the results of the meds are more obvious (although I don't think there would be much difference on the lowest dose). FWIW, DD is very "over-excitable" and she does calm down a lot on the meds and she isn't as up and down emotionally. In her case I think the "over-excitablity" is actually imnpaired executive functioning and the meds help to stabilize that.
https://en.wikipedia.org/wiki/Attention_deficit_hyperactivity_disorder
