Average voltage values were determined in 41 pre-treatment EEGs of chronic schizophrenic patients. The basic EEG values were significantly correlated with changes in behavioral ratings which occurred after eight weeks of treatment with psychotropic drugs. Thus the EEG served as a yardstick for predicting the degree of behavior changes in schizophrenics under drug therapy: the less ill a patient was initially, the more improvement in terms of psychological scores could be expected from drugs.Abstract Teaser