BackgroundAmong people with schizophrenia (PSZ), reduced mismatch negativity (MMN) is conceptualized as evidence of disrupted prediction error signaling that underlies positive symptoms. However, this conceptualization has been challenged by observations that MMN and positive symptoms are often uncorrelated. The present study tests the hypothesis that reduced MMN is associated with the presence of hallucinations and delusions—specifically—rather than the presence of a psychiatric illness. A second aim was to determine whether the strength of the association with positive symptoms increases for indices that reflect predictions at higher levels of abstraction. MethodsFifty-six PSZ, 34 nonclinical voice hearers (NCVH), and 48 healthy comparison subjects (HCS) completed two MMN paradigms: one with a simple duration deviant type (dMMN), and one with a higher-level, pattern-violation deviant type (pMMN). We additionally measured the repetition positivity (RP), which reflects the formation of auditory memory traces. ResultsWe observed that, although PSZ exhibited the expected pattern of significantly reduced dMMN and reduced pMMN at the trend level compared to HCS, NCVH exhibited a pattern of dMMN and pMMN amplitude that was statistically similar to HCS (p’s>0.64). Similarly, PSZ exhibited a significantly reduced RP slope compared to HCS in the duration condition and a trend-level reduction compared to HCS in the pattern-violation condition. NCVH did not significantly differ from either group in RP slope, in either condition. ConclusionsThese results indicate that the MMN as a prediction error signal does not reflect processes relevant for the manifestation of hallucinations and delusions.