1. A case of psychosis developing during 3 courses of ECT for relief of intractable pain is described.2. The patient's attitude toward her pain could be correlated with other alterations of behavior as disorientation, paraphasic language, and changes in perception and the EEG record.3. In the stage of greatest alteration of function, the patient was euphoric and denied her pain; with a lesser alteration of function she was paranoid and showed a partial denial, while with the least alteration of function she was depressed and completely aware of pain.4. The acutely psychotic behavior that occurred following the cessation of convulsions is compared to the withdrawal syndrome that occurs when drug administration is abruptly stopped.5. The concept of anosognosia is stated. It is suggested that the therapeutic efficacy of ECT in functional depressions derives from the production of a state of brain function in which the mechanism of denial is facilitated in characterologically disposed individuals.