Signs and Symptoms of Nitrogen Narcosis

The following lists the signs and symptoms of nitrogen narcosis at various depths.

Depth: 33-100 feet

• Mild impairment of performance of unpracticed tasks.
• Mildly impaired reasoning.
• Mild euphoria possible.

Depth: 100-165 feet

• Delayed response to visual and auditory stimuli.
• Reasoning and immediate memory affected more than motor coordination.
• Calculation errors and wrong choices.
• Idea fixation.
• Overconfidence and sense of well-being.
• Laughter and loquacity (in chambers), which may be overcome by self-control.
• Anxiety (common in cold, murky water).

Depth: 165-230 feet

• Sleepiness, impaired judgment confusion.
• Hallucinations.
• Severe delay in response to signals, instructions and other stimuli.
• Occasional dizziness.
• Uncontrolled laughter, hysteria (in chamber).
• Terror in some

Depth: 230-300 feet

• Poor concentration and mental confusion.
• Stupefaction with some decrease in dexterity and judgment.
• Loss of memory, increased excitability.

Depth: 300-plus feet

• Hallucinations.
• Increased intensity of vision and hearing.
• Sense of impending blackout euphoria, dizziness, manic or depressive states, a sense of levitation, disorganization of the sense of time, changes in facial appearance.
• Unconsciousness.
• Death.