Autistic Disorder, Asperger’s Syndrome and Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS), have all been put under the same umbrella, Autism Spectrum Disorder ("DSM-V: What Changes May Mean | Autism Research Institute). There are three different levels that come with the diagnosis of Autism Spectrum Disorder. The levels are varied of how much the disorder is affecting the patient, some patients have a more severe case than others. There is more criteria to meet when talking about level three, they have updated the criteria and changed things from the old criteria. Doctors are looking for symptoms like repetitive behaviors, fixated interests, etcetera. Why they changed this was to hope to have a better idea of what autism is and not leaving the parents questioning what their child has. They want the disorder to be more understandable and reliable ("DSM-V: What Changes May Mean | Autism Research