are typically diagnosed at a later age. The modern conception of Asperger syndrome came into existence in 1981, and went through a period of popularization. It became a standardized diagnosis in the 1990s, and was retired as a diagnosis in 2013. Many questions and controversies about the condition remain. Classification The extent of the overlap between Asperger syndrome and high-functioning autism (HFA – autism unaccompanied by intellectual disability) is unclear. The ASD classification is to some extent an artifact of how autism was discovered, and may not reflect the true nature of the spectrum; methodological problems have beset Asperger syndrome as a valid diagnosis from the outset. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published in May 2013, Asperger syndrome, as a separate diagnosis, was eliminated and folded into autism spectrum disorder. Like the diagnosis of Asperger syndrome, the change was controversial and thus Asperger syndrome was subsequently not removed from the WHO's ICD-10; however, it was removed from the ICD-11. The World Health Organization (WHO) previously defined Asperger syndrome (AS) as one of the autism spectrum disorders (ASD) or pervasive developmental disorders (PDD), which are a spectrum of psychological conditions that are characterized by abnormalities of social interaction and communication that pervade the individual's functioning, and by restricted and repetitive interests and behavior. Like other neurodevelopmental disorders, ASD begins in infancy or childhood, has a steady course without remission or relapse, and has impairments that result from maturation-related changes in various systems of the brain. Characteristics As a pervasive developmental disorder, Asperger syndrome is distinguished by a pattern of symptoms rather than a single symptom. It is characterized by qualitative impairment in social interaction, by stereotyped and restricted patterns of behavior, activities, and interests, and by no clinically significant delay in cognitive development or general delay in language. Intense preoccupation with a narrow subject, one-sided verbosity, restricted prosody, and physical clumsiness are typical of the condition, but are not required for diagnosis. Suicidal behavior appears to occur at rates similar to those without ASD. Social interaction A lack of demonstrated empathy affects aspects of social relatability for persons with Asperger syndrome. Individuals with Asperger syndrome experience difficulties in basic elements of social interaction, which may include a failure to develop friendships or to seek shared enjoyments or achievements with others (e.g., showing others objects of interest); a lack of social or emotional