That point at which socially relevant attributes of the patient begin permanently to cease to be operative as conditions for treating him, and when he is essentially regarded as already dead.
Sudnow, D. Passing On: The Social Organisation of Dying. Englewood Cliffs, N.J.: Prentice Hall Inc. 1967:74
A situation in which there is absence of those behaviours which we would expect to be directed towards a living person and the presence of behaviours we would expect when dealing with a deceased or non-existent person.
Kastenbaum, R.J. "Psychological death". In Pearson, L. (ed) Death and Dying. Cleveland, Ohio: Case Western Reserve University Press. 1969:15
A series of losses—loss of identity and loss of the ability to participate in social activities and relationships that eventually culminates in a perceived disconnection from social life.
Norwood, Frances. The maintenance of life: preventing social death through euthanasia talk and end-of-life care: lessons from the Netherlands. Durham, NC: Carolina Academic Press, 2009:7