An evidence for lack of pseudoneglect in patients with schizophrenia: An ERP study

• We examined the effect of number magnitude on the P3 latency.
• For controls, P3 latencies were different between the targets ‘one’ and ‘nine’.
• Patients did not show the effect of number magnitude on the P3 latency.
• The results suggest a lack of pseudoneglect in patients with schizophrenia.

Studies have reported an altered expression of pseudoneglect in patients with schizophrenia, but no study has examined pseudoneglect in schizophrenia at the neural level. We investigated pseudoneglect using the visual P3 event-related potential and the mental number bisection (MNB) task in 21 patients and 25 controls. Using an oddball task, participants were asked to discriminate an infrequent (‘one’ or ‘nine’) from a frequent written number (‘five’). The P3 ERP components were delayed to the targets on the right of the MNL (‘nine’) compared to the targets on the left (‘one’) in controls. The effect of number magnitude on the P3 latency was not observed in the patients. In MNB task, the patients did not show the normal leftward bias observed in healthy individuals. Our findings indicate a lack of pseudoneglect and the presence of an anomalous brain asymmetry in schizophrenia.