Correlates of cerebral event-related slow potentials and psychopathology

The study explored associations between the cerebral event-related slow potentials (ERSP) and psychiatric symptoms and syndromes as reflected by the Present State Examination (PSE) in 36 randomly selected psychiatric in-patients. Independent raters measured the readiness potential (RP), contingent negative variation (CNV) and post-imperative negative variation (PINV) in terms of their amplitude and duration. The 360 individual PSE items were grouped into units of analysis (UA) and further collapsed into groups of units of analysis (GUA). Canonical correlations were computed between two sets of variables (psychological and electrophysiological). Kendall's rank-order correlation was used as the main statistical approach. Some psychotic signs were associated with increased PINV amplitude. Obsessive thoughts, ideas of reference and verbal hallucinations correlated with longer PINV duration. Hopelessness and suicidal thoughts (affect-laden thoughts) as well as first-rank Schneiderian symptoms (FRS) were negatively correlated with CNV amplitude. The results support the hypothesis that CNV and PINV, alone or in combination, can be used to indicate the presence or absence of identifiable psychiatric symptoms and syndromes. The implications of electrophysiological correlates of psychopathology for psychiatric nosology and for the validity of psychiatric symptoms and syndromes were discussed.