Ten survivors of a cardiac arrest who had been treated in a cardiac monitor unit were studied by psychiatric interviews six weeks or more after arrest. Not a single patient could face the full implications of the arrest and called forth various defense mechanisms to control the anxiety evoked by this experience. Frightening and violent dreams belied their often tranquil appearance. The patients developed various theories and explanations to enable them to integrate the experience of "having been dead and reborn." The arrest survivors as well as ten comparative patients without arrest who had been treated in the same monitor unit showed long-standing emotional problems including insomnia, irritability, and a restriction of their activities often beyond what was medically appropriate.
Druss RG, Kornfeld DS. The Survivors of Cardiac ArrestA Psychiatric Study. JAMA. 1967;201(5):291–296. doi:10.1001/jama.1967.03130050025008