Organisms have two basic modes of functioning: safe and defensive. If environment is accessible, rich in sustenance and there are no present threats organisms will grow, replenish and flourish. When under a threat living beings enter the defensive mode shutting down every mechanism that doesn't immediately help in their current situation and that includes immunologic response, tissue regeneration, digestion and advanced thought processes (worth to note is that creativity is one of these). It's working off limited resources, like a fortified city put under a siege that closes itself off and conscripts its dwellers as militia. It's funny to think that this mechanism in general sense works from cellular level to entire societies.
When we're talking about humans and communities, especially one like ours which is separated from the physical, the environment is emotional in nature.