Cabin fever is an affliction that was added in the 'Tireless Menace' update.
Cabin fever is only dangerous when having spent most of six days inside a building. There is a 25-50 day grace period where this cannot happen, as this would only become an apparent problem long after having survived for a long time.
In Interloper difficulty, you can start developing Cabin Fever after the first 10 days.
The only symptom of cabin fever is that the player cannot rest inside for 24 hours.
To treat cabin fever, the player must spend time outside until it goes away and cannot sleep inside for 24 hours.
- Cabin Fever risk can be dealt with in a number of ways, even on interloper.
- The first and most common way is to gather firewood and spend a day in a fishing hut. This method works on all difficulties, requires the most effort, but has the most benefits. It gives early game players a source of parasite free food while boiling plenty of water - a task that all players must do at some time during the week anyway.
- The second and by far the easiest method for dealing with cabin fever is to spend a day in the back of a warm cave. These give a +15 degree temperature bonus and with good late game clothing a player can stay warm in these 24/7 without any fire whatsoever. Spending a day in a cave once out of every 6 days is more than enough to eliminate cabin fever. Interloper players beware, even with complete fur clothing and dual bearskin coats, it is possible to freeze to death in a cave if you get a blizzard during late night/early morning when temperatures are the coldest.
- The third way to battle cabin fever is to sleep in cars or snow shelters. Both methods allow you to sleep outdoors even without a bedroll through the campcraft section in the radial menu (hold spacebar). Snow shelters give a +15 degree temperature boost but should only be used where the player is sure no wolves patrol as they do not stop wildlife attacks. Cars give a +5 degree temperature boost but stop wildlife attacks, and on the easier difficulties are all you will ever need to battle cabin fever. Spending 3-5 hours a day in cars sleeping, repairing, or simply passing time is enough to stave off cabin fever forever.
- The Mountaineer's Hut in Timberwolf Mountain, abandoned lookouts in Mystery Lake and Coastal Highway and the porch on the Pleasant Valley Farmhouse count as "indoors" for cabin fever.
On Interloper cars are still incredibly useful, but you must use them for the last 3-4 hours of the day and the first 2-3 hours of night when temperatures are the highest (a little before and after sunset). Keep in mind sleeping gives you a +3 degree boost for a total of +8 degrees. Even with no fur clothing at all it is possible to sleep 3-4 hours in a car at the end of a day in the first 30-40 days before the world temperature starts dropping really fast. They can also be used late game with crafted fur clothing during the same time of day, but once you have a bedroll you should really be sleeping in the backs of warm cave as it is much warmer and you can get a full 10 hours of rest there without fear of freezing to death.