Differential diagnosis of autism spectrum disorder and early onset schizophrenia: two clinical cases

Historically, children with autism spectrum disorder (ASD) were sometimes diagnosed with schizophrenia or major psychosis. Although significant advancements in the process of differential diagnosis have been made since 1950s, there still exists a problematic delay in diagnosis due to overlap of symptoms. Negative symptoms of schizophrenia can mimic the social difficulties and stereotyped behaviors characteristic of ASD, whereas positive symptoms of schizophrenia can be perceived as restricted and repetitive behaviors, complicating the diagnostic process. The purpose of this paper is to present two clinical cases that highlight the complexities in differential diagnosis of early psychosis, schizophrenia and ASD.

Two females, 14 and 16 years of age, were referred to a free screening clinic in Southern California to be assessed for possible ASD. Both females were referred because of the presentation of restricted and repetitive behaviors and social communication difficulties. Both females and their families were administered a battery of measures to ascertain the youths’ cognitive functioning, adaptive living skills and severity of autism-related behaviors.

The 14-year-old presented with early-stage (prodromal or at-risk mental state) psychosis; 16-year-old met criteria for schizophrenia. Both were referred to clinics specializing in treatment for psychosis and/or schizophrenia. Neither met criteria for ASD.

More published studies are needed on the overlap of symptoms between ASD and schizophrenia to help prevent diagnostic overshadowing of autistic symptoms and promote treatment during the early stages of psychosis. This is particularly important given the strong evidence that early treatment for psychosis improves social, cognitive and functional outcomes.