Eliot, R. S., Breo D. L., & Debakey M. E.
(1989).
Is It Worth Dying For?.
"Alarm and vigilance are triggered by different perceptions of events. Alarm can occur when you perceive a challenge to control; vigilance can occur when you feel a loss of control. Alarm provokes an active response, which may be felt as anger, aggression, or a heightened desire to act. Vigilance more often leads to a passive response and even, in extreme form in animals, to "playing dead." Vigilance may reflect self-doubt or a sense of failure or a feeling of invisible entrapment. Continued too long, it can translate into a common effect of stress—depression. (p. 33)"