SDD, Specific developmental disorder entities

SDD was a classification of disorders characterized by delayed development in one specific area or areas. Specific developmental disorders were contrasted to pervasive developmental disorders which were characterized by delays in the development of multiple basic functions including socialization and communication.

According to CD-10, SDD has four categories of developmental disorders:

1. Specific developmental disorders of speech and language
2. Specific developmental disorders of scholastic skills
3. Specific developmental disorder of motor function
4. Mixed specific developmental disorder.