"ADD", "ADHD" and "LD" are just the mostcommon in the growing alphabet soup of labels associated with learning and behavior disorders. The symptoms range from mild difficulties with concentration in school or work situations to outright inability to learn or perform intellectual tasks, from boredom and restlessness to overt anti-social behavior and violence.
The diagnostic terms cover a great variety of symptoms and situations. There is alot that is not yet understand about how the syndrome, arises and what to do about it. So much attention has been focused on this issue recently that it appears that the country is suffering from an epidemic of learning and behavioral dysfunction.