58 Neurodevelopmental Disorders
Language disorders and social (p ragmatic) communi cation disorder. In some forms
of language disorder, there may be problems  of communication an d some secondary so-
cial difficulties. However, specific language disorder is not usually associated with abnor-
mal nonverbal communication, no r with the presence of restricted, repetitive patterns of
behavior, interests, or activities.
When an individual shows impairment in social communication and social interactions
but does not show restricted and repetitive beha vior or interests, criteria for social (prag-
matic) communication disorder, instead of autism spectrum disorder, may be met. The di-
agnosis of autism spectrum disorder supersedes that of so cial (pragmatic) communication
disorder whenever the criteria for autism spectrum disorder  are met, and care should be
taken to enquire carefully regarding past or current restricted/repetitive behavior.
Intellectual disability (intellectual developmental disorder) wit hout autism spectrum
disorder. Intellectual disability without autism spectrum disorder may be difficult to
differentiate from autism spectrum disorder in very young children. Individuals with in-
tellectual disability who have not developed language or symbolic skills also present a
challenge for differential diagnos is, since repetitive behavior often occurs in such individ-
uals as well. A diagnosis of autism spectrum disorder in an indivi dual with intellectual
disability is appropriate when social communi cation and interaction are significantly im-
paired relative to the developmental level of the individual’s nonverbal skills (e.g., fine
motor skills, nonverbal problem solving). In cont rast, intellectual  disability is the appropri-
ate diagnosis when there is no apparent di screpancy between the le vel of social-commu-
nicative skills and other intellectual skills.
Stereotypic movement disorder. Motor stereotypies are among the diagnostic charac-