What is Autism? Autism is a severe developmental disorder that begins within the first three years after conception. Most autistic children look like other kids, but do puzzling and disturbing things which are markedly different behaviors from those of typical children. In less severe cases on the spectrum (Pervasive Developmental Disorder (PDD) or Asperger’s Syndrome), children usually have speech and might even be intellectually gifted, but they have one or more “autistic” social and behavioral problems. People used to think that autism was irreversible. The good news is that there are now a range of treatments that can be really helpful.