Note: Although this is not a major area of misdiagnosis today, we receive one or two e-mails a week concerning this subject. Social anxiety and Asperger's disorder are very different in nature and should not be confused.
Social anxiety disorder is markedly different than Asperger's Disorder in that Asperger's is a pervasive developmental disorder (also called a milder version of autism) and that people with social anxiety disorder do not display the patterns of behavior expected in definitions A and B.
Asperger's Disorder is "a milder variant" of Autistic Disorder. Both Asperger's Disorder and Autistic Disorder are in fact subgroups of a larger diagnostic category. This larger category is called either Autistic Spectrum Disorders or Pervasive Developmental Disorders" according to Dr. R. Kaan Ozbayrak of the University of Massachusetts Medical School.
Definition A also does not fit because anxiety is not the cause of these behaviors in Asperger's as it is when it occurs in people with social anxiety disorder.
The DSM-IV defines Asperger's Disorder (299.80)
A. Qualitative impairment in social interaction, as manifested by two of the following:
(1) marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction
(2) failure to develop peer relationships appropriate to developmental level
(3) a lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people)
(4) lack of social or emotional reciprocity
B. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
(1) encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus.
(2) apparently inflexible adherence to specific, nonfunctional routines or rituals
(3) stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, complex whole-body movements)
(4) persistent preoccupation with parts of objects
C. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.
D. There is no clinically significant general delay in language (e.g., single words by age 2 years, communicative phrases by age 3 years).
E. There is no clinically significant delay 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.
F. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia.
Note again that having "anxiety" is NOT part of the Asperger's definition.