Effects Along with the bends, which is a risk during the ascent of a dive, narcosis is one of the most dangerous conditions to affect the scuba diver at depth. The most dangerous aspect of narcosis is the loss of decision-making ability, loss of focus, and impaired judgment, multi tasking and coordination. At its most benign, nitrogen narcosis results in relief of anxiety and a feeling of tranquility and mastery of the environment. These effects are similar to both alcohol and familiar benzodiazepine drugs such as Valium (diazepam) and Xanax (alprazolam). Such effects are not harmful unless there are immediate dangers to be dealt with, and often they are not recognized. When more serious the diver may begin to feel invulnerable, disregarding normal safe diving practices. Other effects include vertigo, tingling and numbness of the lips, mouth and fingers, and extreme exhaustion. Paradoxially, badly affected divers may panic, sometimes remaining on the bottom, too exhausted to ascend. The syndrome may cause exhilaration, giddiness, extreme anxiety, depression, or paranoia, depending on the individual diver and the diver`s medical or personal history. An early effect may be loss of near-visual accommodation, causing increased difficulty in close-accommodation reading of small numbers in middle-aged or older divers who already have any degree of presbyopia. Tests have shown that all divers are affected by nitrogen narcosis, though some are less affected than others. Even though it is possible that some divers can cope better than others because of acclimation, training, or special breathing techniques, some effects remain. As with alcohol, these effects are particularly dangerous because even for the same diver, they are not perfectly reproducable at the same depth.