 ADHD Behavior Checklist for Adults Barkley, 1995, Murphy and Barkley, 1995: An 18 Item checklist with 9 Inattention items and 9 Hyperactiveimpulsive items ranging 0 - 3 0: never or rarely 1: sometimes 2: often and 3: very often . Items answered often or very often are scored as present. With age, the threshold criterion for presence of ADHD become lower and is currently accepted as follows: 