Sanity is the ability to maintain rational behavior and thinking. To remain in a rational state of mind, and see rational things. A well known effect of being in the backrooms and being exposed to some of the entities within it, is loss of sanity. Symptoms of a drastic loss of ones mind include, but are not limited to:
Hallucinations, mood swings, irrational thinking, thought loops, violent tendencies, extreme irritability and paranoia, change in eating and drinking habits, and overall recklessness.
If one is to survive for any prolonged periods of time in the backrooms, they are to remain calm, collected, and well fed. Losing your sanity in a place like this will turn you into an Insanity. Though the situation may seem bleak, it does not have to be the end. Considering how important remaining sane is, there are of course several ways to maintain your precious sanity, such as:
Remembering
Reliving memories of your favorite birthday spent with your best friend and mother can stave off paranoia and increase morale. Doing it too much can lead to depression and feelings of longing, so it should be done sparingly to avoid potentially harmful effects in the long run. While something as normal as your name may seem easy to skate over, forgetting who you are can be horrible for the mind. Work into a routine of stating your name, your birthday, and what you like to do in your free time. Remembering the life you came from can stave off paranoia and other ill effects of loss of sanity.
Keeping track of time
The vast hallways of the backrooms can easily lead someone to lose track of time. Knowing how long you've been somewhere, as well as having some degree of control over a situation can mean life or death if your brain is betraying itself. Make a routine of time checks as you wander, but try not to watch the seconds tick by.
Eating and drinking
A full stomach and wet whistle improves mood, lessening the wear and tear being in the backrooms has on a persons psyche. Drinking enough Almond water and eating a good ration of meat or other snacks you may have brought with you can improve mood and provide the body with much needed nutrients, essential to continuing your wander.
Not observing entities
While some entities are not inherently bad for the brain, many beings may be seen as scary to some. Remaining calm in the face of entities may not only lead to your swift escape, but may preserve your sanity as well. If you can avoid looking at them, do so. As detailed in many entries of entities, calmly walking away from them is your best plan of action in most cases.
Remaining sane ultimately differs from person to person. Some can go for weeks without even flinching, others break down in seconds. If you are to find yourself in the backrooms, remain calm, and accept your fate. This is not the end.