Deficient response modulation of event-related brain potentials in schizophrenia

Purpose of review We review recent studies in which event-related potentials were used to investigate schizophrenia in the context of past studies, paying special attention to the influence of factors modulating their amplitude. Recent findings Specific event-related potential components in patients with schizophrenia are relatively insensitive to whether stimuli are repeated at long or short intervals (P50, N1), the stimulus is spoken or heard (N1), the pitch or duration of a tone is different from the preceding tone (mismatch negativity), the stimulus is in the attended or unattended sensory modality (N1 and N2), the motor response is correct or incorrect (error-related negativity), the stimulus is an infrequent target or frequent non-target (P300), and to whether the stimulus is emotionally neutral or salient (P300). Increasingly the relations between event-related potentials, brain structure, activation of brain regions, and the neurotransmitters involved have been a focus of inquiry. In a few cases, clues to a genetic basis for schizophrenic event-related potential abnormalities have been found. Rodent models have been developed for many of the components we reviewed. Summary The schizophrenic deficit expressed by these components seems to lie in systems modulating their amplitude as well as in the intactness of their primary electrical source. So far event-related potential research has not resulted in tests with enough specificity and precision to warrant application to clinical practice. Potential clinical applications include diagnosis of schizophrenic traits and states, measurement of outcomes of pharmacological treatment, and early detection of vulnerability to psychosis.