The idea is good but it needs to be toned down a lot, no one ever died from loneliness rather they died from insanity or simply losing the will to live for the sake of this idea we'll run with Sanity. Simple enough, every player spawns with 80% Sanity (you must be a little crazy to survive an apocolypse) which rises (say 10% a minute) while in direct comms range and degrades slowly outside of it (around 5% an hour) just to add a little flavour the times will be effected by murders/Humanity to reflect paranoia in those who hunt the most deadly prey(about 1 minute per murder to rise and -3% Sanity when murdering.) To encourage teamplay in murderers they'll receive less penalties while in range of another murderer (30 - 50% less). Having more people around should have an effect on each stat, ballpark figure of 2% per person. Now the slow decent in to madness! Sanity: 100% - Sane, clam and almost cheery! Blood loss is reduced by 3 80% - Pessimistic yet determinded, no perks or penalties. 50% - Depressed and lonely, 5% increased change of cold/hypothermia when out in the rain. 30% - On the edge, 5% chance of cold/hypothermia in the rain and 3% increased blood loss. 10% - Loosing it, 10% chance of cold/hypothermia in the rain, 5% increased blood loss. 0% - Insane the world is a mushroom and I'm just a purple elephant, lets go dancing! Heavy breathing, increased heartbeat, 20% chance of cold/hypothermia in the rain, 10% increased blood loss but on the upside the trees are made of candy why not give 'em a lick?.