ELECTROENCEPHALOGRAPHIC FINDINGS IN FUNCTIONAL PSYCHOSES - STATE OR TRAIT INDICATORS

The clinical significance of electroencephalographic (EEG) changes in patients with functional psychoses is not yet clearly defined, particu larly whether these changes are state indicators or trait indicators. In the present review: the EEG abnormalities in schizophrenia are disc ussed. In early EEG studies of schizophrenics, the various specific EE G patterns were suggested to be trait indicators. but those findings w ere not confirmed. The EEG patterns of some patients with catatonic sc hizophrenia, especially periodic catatonia; were thought to be episode or state indicators; and some of the patients diagnosed as having aty pical psychoses in Japan were suggested to show state indicator EEG fi ndings. As the computerized and spectral analyses of EEG have advanced , the contradictory findings of EEG in schizophrenia have been reporte d, interpreted as 'hyperstable' or 'hypernormal' EEG findings and 'hyp ofrontal' EEG findings (slow waves in the frontal region). However, no conclusion can be made as to whether these EEG findings are state or trait indicators. On the borderland of functional psychoses, the behav ioral changes in temporal lobe epilepsy were described as a trait indi cator, and the psychotic states in non-convulsive generalized status e pilepticus and acute confusional stares were suggested to be state ind icators. Further studies oi EEG abnormalities in schizophrenia are nec essary; from multi-dimensional perspectives, including in comparison w ith the symptomatic psychoses.