My thesis adviser in graduate school is an "expert" in the area of ADHD. Here is a link to an article he wrote about some of the things you would look for if you suspect ADHD. Good luck!
http://www.eric.ed.gov/ERICWebPortal/custom/portlets/recordDetails/detailmini.jsp?_nfpb=true&_&ERICExtSearch_SearchValue_0=ED450292&ERICExtSearch_SearchType_0=no&accno=ED450292