[Clinical diagnosis of autism]

Abstract

Introduction: The disorders of the autistic spectrum form a collection of symptoms due to dysfunction of the central nervous system with great variations in the degree of severity. Autism is considered to be a generalized disorder of development (DSM-IV). Autism is not defined as a specific disease, since it does not have a specific aetiology.

Development: There are many syndromes related to autism, but most of these disorders are not selective and show a combination of autistic symptoms together with symptoms of neurological dysfunction. There is no specific aetiology, although in recent years genetics have been shown to be important. The prevalence varies between 1 and 1.2/1,000. Boys are more often affected than girls, in a proportion of 3-4 to 1. Diagnosis is clinical and is based on alterations of social interaction, problems of communication and also a restricted range of activities and interests (DSM-IV). There are anomalies associated with behaviour problems, such as delay in speaking, mental retardation, sensorial defects and motor difficulties.

Conclusions: Over 75% of autistic children have mental retardation, and this proportion is higher in severe cases, especially when the children have attention deficit with hyperactivity. These children have many of the typical signs of autism: stereotyped movements, inappropriate language, obsessive behaviour with little mental flexibility, naivety and little skill in social interaction. In these cases it is difficult to draw the line between mental retardation and autism.