1. Impaired reciprocal social interaction (at least two).

2. Restricted repertoire of activities and interests (at least one).

3. Symptoms cause clinically significant impairment across areas of functioning (e.g., social, educational, occupational, etc.).

4. No history of delays in the general development of syntactic language, with single words developing by the age of 2 years and communicative phrases developing by the age of 3 years.

5. No significant delays or impairments in cognitive functioning, age-appropriate self-help and adaptive daily living skills, and curiosity about the environment. More recent research has shown that adaptive communication and socialization skills can be quite impaired in many individuals with AS, despite nonimpaired verbal cognitive skills, that is, the child may have good vocabulary and syntax but fail to appreciate social conventions in a conversation.

1. Age of onset. AS is typically recognized after the age of 3 years, when atypical social interaction skills and preoccupied interests become evident. If the symptoms are detected prior to the age of 3 years, then the profile of impairments should not meet the criteria for autism or another pervasive developmental disorder (i.e., there should be no delays in the development of formal language).

2. Language and communication skills. In AS there should be preservation in the development of formal language skills prior to the age of 3 years, and language may even
appear to be a lifeline for the child early on. However, difficulties will arise as the child matures, particularly in pragmatic language (i.e., in the functional and social use of language). Conversational skills tend to be limited to topics of interest and as a result, communicative exchanges become one-sided and circumstantial. A failure to use and respond to nonverbal cues, such as gestures, body posture, and facial expressions is also observed. The rate and volume of speech in AS is frequently atypical, which is consistent with autism.

3. Socialization skills. The early development of socialization skills in AS may initially appear preserved in that social intent is typically present. Impairments in social interaction become evident when the child attempts to negotiate interactions, as when engaging in conversation. Although the child may be aware of and interested in others, their social exchanges become verbose monologues on their topics of interest without any monitoring of the respective interests of their conversational partner. Thus, there is a lack of social and communicative reciprocity.

4. Behavioral problems. Individuals with AS are often accused of conduct problems that tend to result from a lack of social understanding, such as empathy and concern for others. During school years, for example, individuals with AS may engage in inappropriate or atypical behaviors that are perceived as behavior problems when in reality they are consequences of the disorder. Unfortunately, these individuals can then become the victim of rejection and/or ridicule from peers, placing them at risk for developing comorbid conditions such as anxiety and depression.

5. Cognitive function. According to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria, cognitive functioning in AS is at or above age level (i.e., IQ > 70). Although this may be the case for generalized IQ scores, the cognitive profiles in AS tend to be highly variable (as in autism), with significant impairments evident in some cognitive abilities. In contrast to individuals with autism whose visual-spatial skills tend to be a relative strength, individuals with AS typically have more facility with verbal information, particularly rote, factually based information. The cognitive profile in AS is often, but not always, indicative of a nonverbal learning disability, where (in part) verbal IQ scores are significantly greater than nonverbal IQ scores.