Our friends say it's darkest
before the sun rises
We're pretty sure
they're all wrong

No Children - Mountain Goats

The researchers discovered that prolonged social isolation leads to a broad array of behavioral changes in astronauts — increased aggressiveness towards unfamiliar astronauts, persistent fear, and hypersensitivity to threatening stimuli. When encountering a threatening stimulus, isolated astronauts remain frozen in place long after the threat has passed. These effects are seen when astronauts are subjected to two weeks of isolation, suggesting that the observed changes in aggression and fear may manifest after only a short period of solitude.