Collapse Immobility

A variant of tonic immobility, collapse immobility has been commonly described as the faint response, in which muscle tone is lost (physical collapse) as well as change in consciousness ranging from compromised to complete loss of consciousness. Collapse immobility was first identified in a 1920 paper on human survival instincts and later added to the defense cascade.

Perhaps the most severe response in the defense cascade continuum, collapse immobility could emerge in the ongoing life and development of the trauma survivor in response to the re-exposure to the traumatic experience or exposure to experiences reminiscent of past trauma. Individuals can experience partial or full loss of consciousness, trembling, weakness, and may or may not retain memory for the fainting episodes.

(related terms:  Sympathetic Nervous System and Parasympathetic Nervous System, defense cascade, freeze, flop, tonic immobility)