I think fear, or panic should be an effect.
Fighting: When you are fighting someone and you get them to barely any health, let's say 2 full hearts, they start to panic, which I will explain later. It will basically end up with you not knowing what's going on until you run into your enemy.
Biomes: If you enter a biome of an enemy faction with at least half your health or hunger, then you get panic.
When you panic, you can hear your heartbeat from the game and you may start seeing things, like, you will see npcs or players but only for like a second, or see them running away. This will disorient the player making it more intense.