Nitrogen narcosis, derived from the Greek word Narke is loosely translated as the "temporary decline or loss of senses and movement." Like any other adventure sport, scuba diving comes with some associated risks. Nitrogen narcosis or getting "narked" is one of them.
Nitrogen narcosis is related to the increased solubility of gases in body tissues due to being subjected to increased pressures at depth. Likened by many scuba divers as a similar feeling to being drunk, nitrogen narcosis is also known as "Martini's Law" with the rough guide that it is the equivalent of drinking one martini on an empty stomach for every 10 feet that you descend! The effects of nitrogen narcosis normally occur at depths of around 30m (100 feet) and below and it is not possible to develop a tolerance to the effects, however, the symptoms are completely reversible by ascending to shallower depths. Learn more through this video about nitrogen narcosis and its effects.
At depth, nitrogen narcosis affects the body by leading to a loss of decision making, and the ability to focus, along with impaired judgement, multi tasking and co-ordination. If you have ever taken the PADI Advanced Open Water course, you may well remember being given a series of mental tests under timed conditions on land, and then underwater at depth to compare judgement. My own test whilst on a diving holiday in Sharm el Sheikh 5 years ago did not really go to plan. On land I had no problems writing the alphabet backwards in a respectable time, but underwater, my instructor wrote on the slate that I should draw a heptagon. I was never a natural mathematician at school, and so my hesitation led to my instructor believing that at 30m down, I was narked (when in reality even on land it takes me a long time to work out how many sides are on a heptagon - is it 5?!).
Whilst nitrogen narcosis can be very serious as some divers have a disregard for normal dive practices, if you know your limits, have good equipment and dive under supervision, the effects can be reversed almost immediately by ascending a little shallower. Most divers with a decent number of deep dives under their belt will I'm sure be familiar with getting "narked" and often have funny anecdotes to recount. Tales of offering fish oxygen from the alternative air source (the spare breathing apparatus) are common, as are accounts of euphoria and uncontrollable giggles (not great for your air consumption!). A personal favourite of ours here at Dive in Style is a diver that we know who uses depth and the effects of narcosis to write poetry on his dive slate as he believes it is here that his mind is at its most relaxed!
As with most things in life, safety comes first, however if you enjoy getting drunk but can't stand the hangovers, maybe scuba diving is the hobby for you!