Disorders in which there is a delay in development based on that expected for a given age level or stage of development. these impairments or disabilities originate before age 18, may be expected to continue indefinitely, and constitute a substantial impairment. biological and nonbiological factors are involved in these disorders. (from american psychiatric glossary, 6th ed)

Developmental disorders comprise a group of psychiatric conditions originating in childhood that involve serious impairment in different areas. There are several ways of using this term...