Basic sensory risk markers of schizophrenia in autism spectrum disorder: A systematic review and meta-analysis

Aims: Neurophysiological impairments in basic sensory processes are a hallmark feature in schizophrenia (SZ) and are commonly reported in individuals at-risk of developing SZ. Autism spectrum disorder (ASD) is linked to a higher incidence of later psychotic disorders, including SZ. However, it remains unclear whether basic sensory risk markers for SZ are equally characteristic of ASD. Methods: We performed a systematic review and subsequent meta-analyses of basic sensory risk markers for SZ in ASD. Following PRISMA guidelines, we included 44 studies, investigating prepulse inhibition of the startle reflex (PPI), P50 suppression, mismatch negativity (MMN), N100, and P200 amplitudes. Meta-analyses were conducted for measures with data from ≥ five studies using comparable methodology. Results and Conclusions: Patient groups were predominantly male (~80%) with a mean age of 15.6 years. Findings were mixed, with high heterogeneity in all parameters except %PPI and startle amplitude. PPI, P50 suppression, and MMN qualified for meta-analyses, which revealed significant reductions in duration MMN and P50 amplitude to the first stimulus of paired-click paradigms. Although variability in methods precluded meta-analysis, most visual oddball studies reported significantly increased N100 amplitudes in ASD compared to controls, opposite to the decreased N100 amplitude typically observed in SZ. Coupled with preserved %PPI in ASD, these findings suggest that the N100 ERP and PPI may help differentiate between the two conditions. Simultaneously, other SZ-linked risk markers appear in ASD, and heterogeneity across samples suggests potential neurophysiological subgroups. Future research should apply standardized paradigms in sex- balanced, age-appropriate cohorts to clarify their clinical relevance.