Asperger's syndrome and autism are both autism spectrum disorders and they are similar in many ways.The main differences between them are that there is speech delay in autism, but not in Asperger's syndrome, and mental retardation can (but doesn't always) co-exist with autism, but not with Asperger's syndrome. The severity of those disorders varies a lot between individuals, but autism covers a broader part of the autism spectrum than Asperger's syndrome does. Asperger's syndrome and high functioning autism are nearly the same and are generally mild to moderate in severity, but low functioning autism is generally more severe.There are plans about changing the diagnostic criterias in 2013 and lumping Asperger's syndrome and autism together under one diagnosis, autism, so they will no longer be considered two different disorders.