Nitrogen narcosis (rapture of the deep)

Nitrogen narcosis is a state of impaired mental function caused by high pressure. It feels like being drunk because the nitrogen gas affects your central nervous system. Most divers start feeling the effects around 30 m while they are on air.

Symptoms vary between individuals. You might feel euphoria or extreme anxiety depending on your biology. I once saw a student in Koh Tao try to take his mask off at 35 m because he felt too warm. This is a dangerous mistake.

Always watch your buddy closely. If you feel confused, ascend 5 m immediately to reduce the pressure. You should avoid deep dives on air if you are tired or stressed since these factors make narcosis hit much harder.