Psychosis in general and acute relapse of bipolar illness, in particular, are associated with elevated catecholamine excretion, cardiovascular changes, and changes in intracellular calcium concentration. In an effort to determine if these changes result in observable ECG abnormalities, we retrospectively examined ECG parameters of acutely disturbed bipolar and schizophrenic patients. There were no discrete patterns of abnormalities, and no significant differences were observed between the two patient groups. Most ECG changes in acutely hospitalized bipolar and schizophrenic patients appear to be benign.