 Narcosis while diving ( also known as nitrogen narcosis , inert gas narcosis , raptures of the deep , Martini effect ) , is a reversible alteration in consciousness that occurs while diving at depth . It is caused by the anesthetic effect of certain gases at high pressure . The Greek word <unk> ( narcosis ) is derived from <unk> , " temporary decline or loss of senses and movement , numbness " , a term used by Homer and Hippocrates . Narcosis produces a state similar to drunkenness ( alcohol intoxication ) , or nitrous oxide inhalation . It can occur during shallow dives , but does not usually become noticeable at depths less than 30 meters ( 100 ft ) . 
