What is the recommended treatment for a diver experiencing nitrogen narcosis?

The recommended treatment for a diver experiencing nitrogen narcosis is to return to shallower depths. This condition occurs due to the effects of nitrogen under pressure, leading to symptoms similar to intoxication. By ascending to shallower water, the partial pressure of nitrogen decreases, which alleviates the symptoms of narcosis.

Staying at the same depth might prolong or worsen the effects of nitrogen narcosis, while ascending slowly is important in many diving situations to avoid decompression sickness but does not directly address the issue of narcosis, which needs immediate action to mitigate its effects. Using supplemental oxygen isn't a typical treatment for nitrogen narcosis, as the primary solution involves reducing exposure to high nitrogen pressures rather than addressing hypoxia or similar issues. Therefore, the safest and most effective course of action is to ascend to shallower depths.