Attention deficit disorder (ADD) is one of the three subtypes of Attention-deficit hyperactivity disorder (ADHD). The term was formally changed in 1994
Attention deficit hyperactivity disorder (ADHD) is a developmental disorder. It is characterised primarily by "the co-existence of attentional problems and hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age.
The autism spectrum or autistic spectrum describes a range of conditions classified as pervasive developmental disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Pervasive developmental disorders include autism, Asperger syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), childhood disintegrative disorder, and Rett syndrome, although usually only the first three conditions are considered part of the autism spectrum.
Autism Spectrum Disorders The different forms of autism are thought to overlap considerably. But the fact that there is wide variation in symptoms among children with autism led to the concept of autism spectrum disorder. Autism seems to be on the rise, and autism spectrum disorders affect between two and six children out of every 1,000 in the U.S.