Schizophrenia and autism were linked in many researchers’ studies. Only since the 1960s, medical professionals began to have a separate understanding of these two disorders. Since 1980, Kanner’s so called early infantile autism is listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM). Precisely because of the vague distinction between schizophrenia and autism, the DSM came out with a more accurate definition of autism in 1987. Henceforth, early infantile autism is called autism disorder. Furthermore, for the first time the DSM introduced standardized criteria to diagnose autism. The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders expanded the definition of autism and included milder cases of autism. But especially the Asperger’s syndrome was added in 1994. With the release of the fifth edition of the DSM in 2013 the subtypes of autism are summarized into the general term Autism Spectrum Disorder (ASD). Individuals are now diagnosed on an autism spectrum with varying levels of intensity (mild, moderate and severe).