In the United States, the factors involved in making an Asperger's diagnosis are generally the symptoms listed in the standard manual of mental health disorders. The symptoms include below-average non-verbal communication skills, compulsive routines, and certain language or speech impairments. To make a diagnosis, a psychiatrist will usually meet with a child and interview him or her as well as the family. A period of observation, combined with the use of autism spectrum checklists, will help the psychiatrist make the diagnosis. The experience of the psychiatrist will also help to make a diagnosis of Asperger's or perhaps another of the autism spectrum disorders.
The most important factors in a diagnosis are the symptoms of Asperger's syndrome. These are typically social and behavioral. Common examples include literally interpreting expressions, difficulty understanding others' emotions, and social awkwardness or withdrawal. These symptoms and others are listed in what are called inventories, or checklists, and can help a psychiatrist make the diagnosis.
To diagnose a child with Asperger's syndrome, the child is usually brought into the offices of a school psychologist or clinical psychiatrist. As there are no medical tests for Asperger's, the evaluation will likely include an interview with the child, separate interviews with family or parents, and a period of observation. An IQ test may also be given to help distinguish between Asperger's syndrome and another type of autism spectrum disorder. Interviews will likely include questions about the child's interests, school performance, and social interactions, among others. If the meeting is thorough enough, an Asperger's diagnosis can be made in one session.
In the United States, psychologists and psychiatrists use the current edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) to make an Asperger's diagnosis. This guide, published by the American Psychiatric Association (APA,) cites deficits in social skills and limited behavior or recreational interests as two major categories of symptoms. Other criteria in the DSM include normal language development, negative impacts on work or educational ability, and normal intelligence and development outside of social skills and restricted behaviors. While the DSM lists the symptoms typical of Asperger's syndrome, it is also intended to be used by professionals with clinical and observational experience.
Sometimes an Asperger's diagnosis is made in the school or educational setting. In the United States, the school's criteria for an Asperger's diagnosis differ somewhat from those in the DSM. To make an Asperger's diagnosis for the purpose of special education opportunities, the federal definition of autism is used, which does not distinguish between autism spectrum disorders. This distinction might be confusing, but won't mean that the child will be treated any differently.