Abstract In 39 studies on 37 patients with behavioral disorders requiring hospitalization on a psychiatric ward, only 3 patients failed to show electroencephalographic abnormalities after they had received 500 mg. of chloralose plus 1 2 mg. of scopolamine. Six of this group showed EEG abnormalities during baseline recordings with hyperventilation. Only 7 of the 37 had a history of grand mal or psychomotor seizures. In 15 voluntary controls with no evidence of either epilepsy or severe behavior disorder, only 4 were activated. All activated controls had some irregularities in the baseline recording which, although they might not have been considered abnormal were, nevertheless, deviations from the expected pattern. Activation, which, with one exception, started within the first hour and reached a maximum within the second, consisted of theta-delta activity that was often focal at first but tended to generalize later. Occasionally sharp waves or spikes would be seen. The abnormality would be continuous or paroxysmal and was often associated with an increase in symptoms or behavioral abnormalities. In 8 patients with subcortical chronically implanted electrodes, there was no consistent pattern of subcortical activation before involvement of the cortical areas. Like the clinical studies, the activation often occurred focally then became generalized. Only one patient lost consciousness, and although she showed focal rhythmic clonic movements there was no generalized tonic-clonic convulsion. In view of the fact that only 7 of the 34 patients who were activated had a history of seizures, one should be extremely cautious in interpreting scopolamine-chloralose activation as evidence of epilepsy. Whether this procedure will be useful in identifying a specific group of behavior disorders can only be determined by extending activations to much larger series of patients and controls.