These disorders overlap in the sense that a portion of their clinical features are shared. Most of the time, when parents and professionals are referring to ASD, they are talking about Autism, PDD-NOS, or Asperger's Disorder. The assumption is that with careful assessment the PDDs can be differentially diagnosed. Diagnosis of autistic features in children who do not qualify for classical autism has increased during the past decade. The result of a neurological disorder that affects functioning of the brain, autism and its behavioral symptoms occur in approximately fifteen out of every 10,000 births.
Autism is four times more common in boys than girls.
It has been found throughout the world in families of all racial, ethnic, and social backgrounds. No known factors in the psychological environment of a child have been shown to cause autism. Abnormal responses to sensations. Absence or delay of speech and language, although specific thinking capabilities may be present. Abnormal ways of relating to people, objects, and events.