Same. Autism & autistic disorder are the same. As of may 2013, the new diagnostic manual is changing things, getting rid of asperger's disorder and pervasive developmental disorder & creating an umbrella term of autism spectrum disorder (ASD) to include individuals with lifelong problems in social interactions & unusual interests or bizarre behaviors. Exact changes are not yet public but will be soon.
See detail answer. Preferred term: ASD or Autism Spectrum Disorder. It included autistic disorder ( Classic autism, early infantile autism, Childhood autism ( Kanner's autism) and childhood disintergrative disorder, Pervasive develomental disorder-not otherwise specified and Asperger disorder.