What actions should a diver take when diagnosing nitrogen narcosis?

When diagnosing nitrogen narcosis, the most effective action for a diver is to stay calm and safely ascend. Nitrogen narcosis is a condition caused by the increased partial pressure of nitrogen at greater depths, leading to impairment in judgment and cognitive function. Maintaining calmness is crucial because panic can exacerbate the situation and lead to unsafe diving behavior, such as rapid ascents or erratic movements.

Ascending safely is essential because the effects of nitrogen narcosis decrease at shallower depths. By ascending gradually, the diver can reduce the effects of narcosis while also adhering to safe diving practices to avoid other potential issues, such as decompression sickness.

The other options, such as slowing down ascent immediately or experimenting with depth changes, could lead to unsafe diving practices. Rapid ascent could lead to a variety of complications, including barotrauma or decompression sickness. Experimenting with depth changes is not advisable as it could worsen the symptoms of nitrogen narcosis and increase the risk to the diver's safety. Additionally, while notifying other divers may be important in certain circumstances, the priority should be on managing the situation effectively and safely ascending.