The essential features of Asperger's Disorder are severe and sustained impairment in social interaction (Criterion A) and the development of restricted, repetitive patterns of behavior, interests, and activities (Criterion B). The disturbance must cause clinically significant impairment in social, occupational, or other important areas of functioning (Criterion C). In contrast to Autistic Disorder, there are no clinically significant delays in language (e.g., single words are used by age 2 years, communicative phrases are used by age 3 years) (Criterion D). In addition, there are no clinically significant delays in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior (other than in social interaction), and curiosity about the environment in childhood (Criterion E). The diagnosis is not given if the criteria are met for another other specific Pervasive Developmental Disorder or for Schizophrenia (Criterion F).
Asperger's Disorder is sometimes observed in association with general medical conditions that should be coded on Axis III. Various nonspecific neurological symptoms or signs may be noted. Motor milestones may be delayed, and motor clumsiness is often observed.
Information on the prevalence of Asperger's Disorder is limited, but it appears to be more common in males.
Asperger's Disorder appears to have a somewhat later onset than Autistic Disorder, or at least to be recognized somewhat later. Motor delays or motor clumsiness may be noted in the preschool period. Difficulties in social interaction may become more apparent in the context of school. It is during this time that particular idiosyncratic or circumscribed interests (e.g., a fascination with train schedules) may appear or be recognized as such. As adults, individuals with the condition may have problems with empathy and modulation of social interaction. This disorder apparently follows a continuous course and, in the vast majority of cases, the duration is lifelong.
Although the available data are limited, there appears to be an increased frequency of Asperger's Disorder among family members of individuals who have the disorder.
Asperger's Disorder is not diagnosed if criteria are met for another Pervasive Developmental Disorder or for Schizophrenia. For the differential diagnosis with Autistic Disorder, see Autistic Disorder. For the differential diagnosis with Rett's Disorder, see Rett's Disorder. For the differential diagnosis with Childhood Disintegrative Disorder, see Childhood Disintegrative Disorder. Asperger's Disorder must also be distinguished from Obsessive-Compulsive Disorder and Schizoid Personality Disorder. Asperger's Disorder and Obsessive-Compulsive Disorder share repetitive and stereotyped patterns of behavior. In contrast to Obsessive-Compulsive Disorder, Asperger's Disorder is characterized by a qualitative impairment in social interaction and a more restricted pattern of interests and activities. In contrast to Schizoid Personality Disorder, Asperger's Disorder is characterized by stereotyped behaviors and interests and by more severely impaired social interaction.
(299.80 Asperger's Disorder from the Diagnostic and Statistical Manual of Mental Disorders: DSM IV)