The natural history of acute organic mental syndrome after bilateral electroconvulsive therapy.

Thirty-one patients undergoing electroconvulsive therapy (ECT) were followed prospectively for the development of acute organic mental syndrome (AOMS); 15 patients (48.4%) developed AOMS during ECT. For these 15 patients, the average number of ECTs before development of AOMS was 5.5 with average duration of AOMS being 20.1 days. Comparison of these 15 patients to the 16 patients who did not develop AOMS for diagnoses, demographic data, pre-ECT laboratory data, and medications, differed only in exposure to psychoactive medications and prior presence of major medical illness.