For diagnosis of autism spectrum disorder, a child must display symptoms in two core areas: social communication and social interaction, and restrictive, repetitive patterns of behavior, interests, and activities. The symptoms must be impairing, and must be present in the early developmental period—they are typically recognized in a child’s second year—but they may not be fully manifest until a child is older and the social demands exceed his abilities. ASD can be diagnosed as early as 24 months.
In the category of social communication and social interaction, a clinician will look for persistent deficits in social reciprocity, such as back-and-forth conversation and sharing of interests; nonverbal communication, including body language and gestures; and difficulty developing, understanding, and participating in age-appropriate relationships.
In the category of restrictive or repetitive patterns of behavior, a clinician will look for two of the following: stereotyped movements, actions or use of speech, inflexible insistence on routines and rituals, fixated and intense interests, and sensory problems, either from too much sensory input or two little.
According to the new criteria, these symptoms must be significantly impairing, and a clinician will specify the severity of each of the symptoms on a three-tiered scale that reflects the amount of support a child would need—requiring support, substantial support, or very substantial support—to function successfully.
Given that children with autism also frequently have cognitive impairment (now called intellectual development disorder), children should not be diagnosed with autism unless their social communication deficits are greater than would be explained by their cognitive impairment.
If a child has impairment in social communication and social interaction but doesn’t have restrictive and repetitive behaviors, he is more likely to be diagnosed with a new disorder called social communication disorder.