Although there are very few prospective studies of CAP, organic causes of the problem are misdiagnosed probably in less than 5% of adolescents. Response to treatment seems to be better in males who have had signs and symptoms for less than 6 months, and is rather poor for patients with complaints exceeding 2 years. An organized nomenclature is necessary for classifying dysfunctional disorders, and physicians must recognize that these patients represent a heterogeneous population. In general, adequate data for the number of the adolescent population affected by these diseases is not available, so that physicians are still required to depend to a large extent on speculation and anecdotal information in assessing and managing these patients.