Is autism spectrum disorder common in schizophrenia?

A century ago, Kraepelin and Bleuler observed that schizophrenia is often antedated by "premorbid" abnormalities. In this study we explore how the childhood neurodevelopmental problems found in patients with schizophrenia relate to the current concept of autism spectrum disorder (ASD). Forty-six young adult individuals with clinical diagnoses of schizophrenic psychotic disorders were assessed. The Structured Clinical Interview for DSM Disorders (SCID-I) was used in face-to-face psychiatric examination of each individual. In 32 of the 46 cases (70%), collateral information was provided by one or both parents. The Diagnostic Interview for Social and Communication Disorders - eleventh version (DISCO-11) was used when interviewing these relatives. This instrument covers, in considerable depth, childhood development, adaptive functioning, and symptoms of ASD - current and lifetime. There is a strict algorithm for ASD diagnosis. About half of the cases with schizophrenic psychosis had ASD according to the results of the parental interview. The rate of ASD was strikingly high (60%) in the group with a SCID-I diagnosis of schizophrenia paranoid type. The findings underscore the need to revisit the DSM's "either or" stance between ASD and schizophrenia.