The specific event you mention (my paraphrasing: loss of consciousness and motor control leading to a sleep/coma-like state due to acute circumstantial stress) might best be classified according to @Monacraft's excellent answer. To build on that somewhat, we've discussed in chat that there might be important distinctions among various levels of consciousness, such that, per your example, "sleep" might be usefully different from "passed out." I've noted my own vague familiarity with theories of consciousness that model it in terms of discrete levels of awareness. My off-the-cuff proposal for such a model was as follows:
$$\text{fully alert > calm}\ge\text{trance}\ge\text{drowsy} \\ \text{> REM sleep > deep sleep > "KO'd" unconscious}\\\text{> deep coma}\ge\text{Near-death experience}\ge\text{vegetative > kaput}$$
I see that Wikipedia has its own page about levels of consciousness as well, which lists the following levels as a summary (using GRE-level vocab), for which it cites Porth (2007):
$$\text{conscious > confused > delirious > somnolent > obtunded > stuporous > comatose}$$
The above Wikipedia page even mentions and links to a separate page about the Glasgow Coma Scale (cf. Gill, Reiley, & Green, 2004), which is one of apparently many scales in medical use for measuring differences among unconscious states, so it seems one could take an even finer-grained or fully continuous approach to modeling individual differences in degree of conscious awareness. A Google image search for "levels of consciousness" also leads to a lot of rather suspicious-looking diagrams of levels of consciousness above sleep, so a continuous dimensional model would probably help reduce a lot of this theoretical mess if theorists could somehow be made to agree with it unanimously. Then again, one strong counterargument would be the often sudden loss of muscle tension that can occur in rapid transitions from awake to unconscious. That might better support a model with at least one such discrete state change.
Anyway, this reminds me of general adaptation syndrome (GAS), which describes normative stress response in terms of a curvilinear model of resistance as a continuous dependent variable changing over time:
Thus another conceivable, more general answer might simply be "exhaustion", as above. One source on GAS that I was able to find online just now mentions "passing out" explicitly in association with the exhaustion stage, so this at least tentatively supports the interpretation of exhaustion as potentially leading to unconscious, sleep-like levels of consciousness, though maybe more authoritative references than this could be found to provide such support (please comment or edit if you find any). Another parallel worth drawing here is between "resistance to stress" and emotional arousal, the vertical axis on the circumplex model of emotion I mentioned in another answer here. Given a stressful circumstance, we'd of course be looking at the left side of that diagram, and reinterpreting the rise and fall of resistance as the transition from neutral, to nervous, to gloomy, and finally sluggish or tired. This might help explain why depression is a related issue. Long-term depression (such as in people suffering a major depressive episode) naturally leaves a person exhausted, and maybe more likely to just pass out when overwhelmed by stress, because such a person is probably closer to "overwhelmed" from the outset.
In our chat, we've discussed some other complexities on the diathesis side of the stress response model; I think some of that is worth re-posting here. First, a handy (if simplistic) diagram from Wikipedia on the diathesis-stress model:
To apply this here, let's define the negative outcome as that described in the OP; the positive outcome as simply retaining consciousness, self-control, and effective coping capability; the negative environment/experience as the class of traumatic events described in the OP; the positive environment/experience as ordinary experience; the resilient individual as the subpopulation of people who would score at least one standard deviation (SD) above average on measures of protective characteristics and one SD below average on diathesis-exacerbating characteristics; the vulnerable individual as the opposite subpopulation; and both lines as oversimplified predictions of average tendencies subject to probabilistic error. This allows us to accommodate a potentially endless list of individual differences that could moderate the normative tendency to change one's level of conscious awareness in response to extremely shocking, traumatic stress. For now, I'll limit myself to mentioning only two, particularly relevant differences:
- Hardiness is the prototypical stress-resistance trait; you'd expect a resilient individual to have lots.
- Neuroticism, the opposite of emotional stability, characterizes individuals with tendencies toward negative emotionality and stronger stress response. This would make an individual more reactive, likely to experience depression, and thus more likely to suffer chronic exhaustion and be vulnerable.
- It relates to psychiatric illness in general, which relates to syncope (Oh & Kapoor, 1997).
- It's negatively related to hardiness, but partially distinct (Sinclair & Tetrick, 2000), so a neurotic person who also lacks hardiness would be especially vulnerable, and vice versa.
References
Gill, M. R., Reiley, D. G., & Green, S. M. (2004). Interrater reliability of Glasgow Coma Scale scores in the emergency department. Annals of Emergency Medicine, 43(2), 215–223.
Oh, J. H., & Kapoor, W. N. (1997). Psychiatric illness and syncope. Cardiology Clinics, 15(2), 269–275.
Porth, C. (2007). Essentials of pathophysiology: Concepts of altered health states, pp. 835. Hagerstown, MD: Lippincott Williams & Wilkins. ISBN 0-7817-7087-4. Retrieved July 3, 2008.
Sinclair, R. R., & Tetrick, L. E. (2000). Implications of item wording for hardiness structure, relation with neuroticism, and stress buffering. Journal of Research in Personality, 34(1), 1–25.
