Delayed onset and prolonged interictal delirium following electroconvulsive therapy.

Electroconvulsive therapy is safe and effective in the treatment of depression in older individuals. Minor cognitive side effects of electroconvulsive therapy include acute postictal confusion and reversible short-term memory deficits. However, interictal delirium is uncommon in absence of risk factors. Herein, we report the case a depressed male patient without any known risk factors who developed interictal delirium 2 days after his sixth electroconvulsive therapy session. Interictal delirium improved with treatment within 1 week.