Differences in self‐reported psychotic symptoms between patients with autism spectrum disorder and those with schizophrenia

AIM: Patients with autism spectrum disorder (ASD) are prone to develop overt psychosis and share symptom presentations with those with schizophrenia (SZ). This study aimed to explore differences in the distributions of psychotic symptoms among first‐visit patients with ASD, SZ, or a nonpsychiatric diagnosis (N‐PD). METHODS: Data from first‐visit patients were retrospectively collected from medical records from the Department of Psychiatry, Dokkyo Medical University Hospital between June 2019 and May 2021. A total of 254 patients with data on the PRIME Screen‐Revised (PS‐R) assessments were included in our analysis. In the hospital, all psychiatric diagnoses were based on the DSM‐5 diagnostic criteria. RESULTS: In the ASD, SZ, and N‐PD groups, endorsements of perplexity and delusional mood were 15.6% (7/45), 41.5% (44/106), and 1.1% (1/88), and those of perceptual abnormalities were 11.1% (5/45), 40.6% (43/106), and 2.3% (2/88), respectively. Trend analysis clarified that the endorsement of these psychotic symptoms increased from N‐PD to ASD and SZ. In the multivariate‐adjusted multinomial logistic regression analysis, the ASD and N‐PD groups were compared with the SZ group. Higher age and the presence of perceptual abnormalities were associated with lack of an ASD diagnosis, whereas male sex, lack of perplexity and delusional mood, and lack of perceptual abnormalities were associated with N‐PD. CONCLUSION: Our results are preliminary; however, a detailed assessment of positive symptoms might facilitate differentiation between ASD and SZ.