Actually, they can do brain scans that are pretty successful in finding ADHD. The only trouble is - you don't want to do that with a child. Consequently, the new standards for diagnosing ADHD are pretty specific. And it has nothing to do with only observing the child. I don't know where you got that information. Any doctor that did only that should be instantly removed from his practice.
One of the most important changes in the new guidelines is the part which states, "For preschool-aged children, evidence-based behavioral therapy alone is recommended as the first step toward treating ADHD symptoms and associated impairment. Behavioral treatments may include behavioral parent training, classroom management, and/or peer interventions. These behavioral treatments represent a set of behavior-modification techniques that are provided to parents for implementation in the home, at school, or through group-based training sessions and are often delivered by clinical psychologists." In other words - NO DRUGS.
But, as I stated to the original poster two years ago, the symptoms she described don't by themselves point to ADHD. If you would like to post what is worrying you about your child, we may be able to help. Also the child behavior forum (found here - http://www.medhelp.org/forums/Child-Behavior/show/64
) can also be very helpful. Go onto that site and take a look at some of the problems we are able to help with.
Let us know if we can be of help. And consider starting your own post - you definitely have the right to do so. Best wishes.