High-functioning autism

The term "high-functioning autism" was used in a manner similar to Asperger syndrome, another outdated classification. The defining characteristic recognized by psychologists was a significant delay in the development of early speech and language skills, before the age of three years. Other differences were noted in features of high-functioning autism and Asperger syndrome in a study of 112 children in Germany. Studies that looked specifically at HFA have examined anxiety, bipolar disorder, Tourette syndrome, attention deficit hyperactivity disorder (ADHD), and obsessive–compulsive disorder (OCD). Both HFA and OCD have abnormalities associated with serotonin. ==See also==