Some "unusual stresses"
Stress during sleep and stress during anesthesia
Dreaming(REM phase of our sleep), we can experience the same stress as awake. Stress reaction keeps the same physiological course and the fact that a nightmare can make us wake up is a consequence of the activation of the sympathetic system. The possible negative consequences of stress during sleep are not less harmful than that of stress experienced in awake condition.
What is remarkable about the stress reaction, however, is that even under anesthesia, our organism may still react in a nonspecific way. Anesthesia decreases brain activity to great extent, but since the brain cannot be fully "turned off"(that would mean death), in very rare cases, it might detect the unusual condition in which the organism is under anesthesia and trigger the stress reaction. Stress under anesthesia can have very adverse effect on the patient being operated and poses great problems for the surgeons. The mechanisms by which brain can still detect what is going on in the organism, are yet to be researched and explained.
Stress under substance abuse/endocrine problems
This is an enormous topic to explore since the way stress reaction will be changed varies according to the substance/endocrine disorder. Substances may affect the endocrine system but also the brain and then it is very hard to predict the possible consequences. If the substance taken, influences only hormones, this usually results in destruction of hormones' active structure, hence poor initial effect of the stress reaction(alcohol is one example). Of course the majority of substances do not affect the organism so narrowly and their possible effects can be versatile.
As far as the influence of endocrine problems on stress reaction is concerned, things are even harder to generalize: it depends on many variable factors - power of stressors, severity of endocrine disorder, biorhythms, individuality, etc.
Stress in space
Undoubtedly one of the most "unusual" stresses is stress in space. Factors such as gravity, air pressure, ldaylight(which has great impact on emotions) simply do not exist. At the same time cosmonauts are subjected to all possible kinds of stressors - physical, physiological, emotional. For this amazing aspect of stress we provide some links and welcome your contributions, as well.
http://www.spacestress.com/
http://spaceflight.nasa.gov/shuttle/archives/sts-82/crew/answers/answer22.html
http://www.marsacademy.com/text/crew.htm
http://pubs.acs.org/hotartcl/cenear/980525/nasa.html
suggest additional material/new interpretations on the subject
Sites:
http://199.97.97.16/contWriter/yhd7/2000/07/10/medic/7665-0003-pat_nytimes.html
http://anes01.wustl.edu/all-net/english/cardpage/operate/anesthesia/regional-1.htm