This is fascinating to read: [https://www.psychologytoday.com/us/blog/neurosagacity/201701/the-brain-can-work-against-abuse-victims]

"Oxytocin is very responsive to our social environment – it is contextual. Therefore, psychological or physical stressors can result in the release of oxytocin. 

High levels of this neuropeptide can have two completely opposing meanings – it can calm anxiety, as well as heighten it. The oxytocin receptors involved seem to depend on the social context.

Specifically:

    Heightened levels of oxytocin can reduce and calm stress. This is associated with oxytocin receptors located in the amygdala. However,
    High levels of oxytocin is a sign of social distress. This is associated with oxytocin receptors located in the lateral septum. 

This dual role of oxytocin receptors was initially described in studies conducted at the University of California by Dr. Shelley E. Taylor and her research team. She explains that oxytocin can rise under negative social conditions causing a person to seek out better social circumstances."

The author describes what I would associate with the "survival brain reaction" which is a plus-reaction under stress.

On the other hand, "Low levels of oxytocin are often associated with elevated cortisol levels. When cortisol production increases, oxytocin release declines." [https://hghtherapydoctor.us/hormones/oxytocin-hormone-definition-effects-normal-levels/|Source]
Cortisol rises typically under long-term stress. Low levels of oxytocin are found in depressive individuals and in autism. This shows a relation to certain territorial constellations.