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Updated: Aug 29, 2026
Investigating the Effects of Antipsychotics and Schizotypy on the N400 Using Event-Related Potentials and Semantic Categorization
Published on: November 19, 2014
[Distribution of latencies of visual evoked potentials in a sample of schizophrenic patients]
Krzysztof Małyszczak1, Marek Kubiszewski, Witold Pilecki
1Katedry i Kliniki Psychiatrii AM we Wrocławiu.
Aim:
The aim of the study is an analysis of distribution of visual evoked potentials (VEP) latencies in the group of schizophrenic and healthy subjects.
Method:
A study was carried out on a group of 30 patients (8 males and 22 females) with a DSM-III-R diagnosis of schizophrenia (disorganised schizophrenia--5, paranoid schizophrenia--12, residual schizophrenia--6, and undifferentiated schizophrenia--6). During the study 20 patients were given neuroleptics, 10 patients did not receive treatment. A control consisted of 50 healthy persons (25 males and 25 females). A stimulation of a chessboard pattern reversal (0.5 Hz, 30', 50 cd/m2) was applied. Evoked potentials were measured between top of a head (Cz) and occipital leads O1 and O2.
Results:
Schizophrenic patients have frequently prolonged N2 latency, and shortened P300 latency. Three groups of patients have been distinguished, based on a pattern of latencies: (1) patients with prolonged latencies of all the waves (half of the patients), (2) patients with prolonged N2 latency, and shortened P300 latency (one fourth of the patients), and (3) patients with latencies similar to control (one fourth of the patients).
