guage impairment, which is characterized by a history of delay in reaching language mile-
stones, and historical, if not current, structur al language problems (see “Language Disorder”
earlier in this chapter). Individuals with social  communication deficits may avoid social inter-
actions. Attention-deficit/hype ractivity disorder (ADHD), beha vioral problems, and specific
learning disorders are also more common among affected individuals.
Development and Course 
Because social (pragmatic) co mmunication depends on adeq uate developmental progress
in speech and language, diagnosis of social (pragmatic) communication disorder is rare
among children younger than 4 years. By ag e 4 or 5 years, most  children should possess
adequate speech and language abilities to permit identification of specific deficits in social
communication. Milder forms of  the disorder may not become apparent until early ado-
lescence, when language and social interactions become more complex.
The outcome of social (pragmatic) communicat ion disorder is variable, with some chil-
dren improving substantially over time and othe rs continuing to have difficulties persist-
ing into adulthood. Even am ong those who have significant improvements, the early
deficits in pragmatics may cause lasting impa irments in social relationships and behavior
and also in acquisition of other rela ted skills, such as written expression. 
Risk and Prognostic Factors
Genetic and physiological. A family history of autism spectrum disorder, communica-
tion disorders, or specific learning disorder appears to increase the risk for social (prag-
matic) communication disorder.