“Northern European societies are among the few where people sleep alone or with a partner in a private room, and that may have significant implications for mental health in general and for PTSD in particular. Virtually all mammals seem to benefit from companionship; even lab rats recover more quickly from trauma if they are caged with other rats rather than alone. In humans, lack of social support has been found to be twice as reliable at predicting PTSD as the severity of the trauma itself.”
