I found a very interesting link on this... www.adhdtesting.org Which clearly states that its exisitance is subjective entirely, and that there are no physiological tests. 'Diagnosis' is b ythe completion of the standard DSM-IV - a survey of mental capacity and state of mind... "In 1998, The National Institute of Health held a Conference on ADD/ADHD. At the end of this conference they issued this statement: "....We do not have an independent, valid test for ADD/ADHD and there are no data to indicate that ADD/ADHD is due to a brain malfunction."...What a person needs to always remember, again and again, is that NO ?test? has ever been validated in the determination of ADD/ADHD.... ...I would have to follow that this 'syndrome' is a collection of socially difficult behaviour, lending to a mental health problem which many are happy to have labelled and 'validated' to excuse it.