Neurocognitive Processing of Figurative Language in Individuals With Schizotypal Personality Traits: Evidence From an Event-Related Potential Investigation.

BACKGROUND The objective identification of potential neurophysiological markers of schizotypal personality traits represents a major step toward improving early diagnostic strategies in psychiatry. In this study, we investigated the influence of schizotypal personality traits on the neural mechanisms underlying literal and figurative language comprehension, aiming to contribute to the development of neurophysiological markers of schizophrenia spectrum pathology.

METHODS A total of 121 university students were assessed using the Schizotypal Personality Questionnaire (SPQ) and categorized into three groups: low-SPQ (scores <21; n = 60), intermediate-SPQ (scores 21-40; n = 44), and high-SPQ (scores ≥41; n = 16). Participants evaluated 60 literal, 60 idiomatic, and 60 semantically incongruent phrases for meaningfulness, while event-related potentials (ERPs)-specifically N400 and post-N400 Positivity (PNP)-were recorded.

RESULTS The low-SPQ group showed clear N400 differentiation between idiomatic expressions and both incongruent and literal conditions, whereas intermediate-SPQ and high-SPQ groups demonstrated reduced N400 distinctions in the frontal area. At central and parietal sites, participants with increased SPQ scores retained partial differentiation between idiomatic and incongruent phrases, but they failed to differentiate between idiomatic and literal ones. Moreover, participants with intermediate SPQ scores exhibited larger frontal PNP differences between incongruent and idiomatic conditions relative to the low-SPQ group.

CONCLUSIONS These findings indicate that schizotypal traits are associated with poorly regulated semantic processing at the N400 stage, which is accompanied by compensatory activity at later stages of stimulus processing. These findings highlight ERP markers that may support early detection of vulnerability to schizophrenia spectrum disorders.