The invention relates to a method of treating Attention Deficit Disorder (ADD) and Attention Deficit/Hyperactivity Disorder (ADHD) and compositions for topical application of methylphenidate comprising methylphenidate in a flexible, finite system wherein the methylphenidate is present in an amount sufficient to achieve substantially zero order kinetics for delivery to the skin or mucosa of a patient in need thereof over a period of time at least 10 hours.
