I recommend getting a solid, scientific diagnosis first, rather than relying on the paper quizzes that psychologists and doctors use. Most kids end up with a stack of "diagnoses" all of them different!
Find an EEG neurofeedback practitioner who is qualified to work with children (you can find a list at the www.bcia.org website). The clinic will place electrodes on the kid's head (doesn't hurt, but some kids don't like it). The electrodes will pick up the electrical wave patterns in the brain and quantify and graph them on a computer screen.
There are well known patterns for ADHD, Asperger syndrome, Tourette's, mild brain trauma, etc.
The clinic can identify which wave patterns are causing the difficulties and prescribe a neurofeedback treatment program that will teach the brain to pull those wave patterns back into a normal pattern. Again, harmless, but it takes a long time.
We did it last year. My son, who had tics so bad he couldn't go to school, was so agitated he spent most of his days in fear, was obsessive-compulsive and hypersensitive, now is completely symptom-free. He is no longer on any medications. He is happy, calm, and steadily learning every day all the things he missed while he was in the fog of brainwave soup for so many years.