Qualitatively distinct factors contribute to elevated rates of paranoia in autism and schizophrenia.

A converging body of clinical and empirical reports indicates that autism features elevated rates of paranoia comparable to those of individuals with paranoid schizophrenia. However, the distinct developmental courses and symptom manifestations of these two disorders suggest that the nature of paranoid ideation may differ between them in important and meaningful ways. To evaluate this hypothesis, we compared patterns of responses on the Paranoia Scale between actively paranoid individuals with schizophrenia (SCZP), individuals with schizophrenia who were not actively paranoid (SCZNP), adults with an Autism Spectrum Disorder (ASD), and healthy controls. Despite an overall similar level of heightened paranoia in the ASD and SCZP groups, discriminant correspondence analysis (DiCA) revealed that these groups were characterized by unique underlying factors. Paranoia in the SCZP group was defined by a factor based upon victimization, suspicion, and threat of harm. Whereas paranoia in the ASD group was partially characterized by this factor, it was distinguished from SCZP by an additional pattern of responses reflective of increased social cynicism. These findings indicate that paranoia in ASD is supported by qualitative factors distinct from schizophrenia and highlight mechanistic differences in the formation of paranoid ideation that may inform the development of disorder-specific treatments.