1. A sudden collapse, as of an evacuated vessel, in which there is a bursting inward rather than outward as in explosion.
2. A type of behaviour therapy, similar to flooding, during which the patient is given massive exposure to extreme anxiety-arousing stimuli by being asked to describe, and thus relive in his imagination, those life events or situations typically producing these overwhelming emotional reactions. As the patient does so, the therapist attempts to extinguish the future influence of such unconscious material over the patients behaviour and feelings, and previous avoidance responses to the stimuli are replaced by more appropriate responses.