I'm reminded of stories about lighthouse keepers driven mad by their isolation. There was something more insidious happening however.
To keep the lighthouse lamp perfectly aligned with the horizon it was floated on a pool of liquid mercury. The heat from the lamp evaporated the mercury exposing the hapless lighthouse keepers to the brain destroying effects of mercury vapors.
I seem to crave isolation and often worked on that above-mentioned horizon alone on my boat - I sorta felt like I was at home.