Automatic sensory information processing abnormalities across the illness course of schizophrenia

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Chronic schizophrenia is associated with reduced mismatch negativity (MMN) and P3a event-related potentials, indicating sensory discrimination deficits.
• These auditory event-related potentials have not been extensively studied in the early stages of psychotic illness.

Purpose of the Study:

• To investigate mismatch negativity (MMN), P3a, and reorienting negativity (RON) across the schizophrenia spectrum.
• To examine auditory event-related potentials in individuals at risk for psychosis, recent-onset schizophrenia, chronic schizophrenia, and healthy controls.

Main Methods:

• Assessed MMN, P3a, and RON using a duration-deviant auditory oddball paradigm.
• Evaluated 118 participants across four groups: at-risk for psychosis (n=26), recent-onset patients (n=31), chronic patients (n=33), and normal controls (n=28).

Main Results:

• All patient groups exhibited frontocentral MMN and P3a deficits.
• At-risk individuals showed intermediate MMN and P3a amplitudes between controls and recent-onset patients.
• Recent-onset and chronic patients, unlike at-risk subjects, displayed reduced RON amplitudes compared to controls. Negative symptoms in at-risk individuals correlated with P3a and RON deficits.

Conclusions:

• Auditory processing abnormalities, including sensory discrimination and attention reorienting, are present early in schizophrenia.
• MMN and P3a reductions observed before psychosis onset suggest their potential as early schizophrenia biomarkers.
• Findings indicate possible progressive worsening of these deficits across illness stages.