Nitrogen Narcosis?

There was mention of thinning air which made me think they were suffering from nitrogen narcosis which causes paranoia, anxiety, skewed perception, impaired judgement, auditory and visual hallucinations. Anyone else thought the same?

I really enjoyed the movie and can't believe the studio had so little faith in it. It's definitely one of those thrillers that gets the mind stimulated. Wish I had seen it on the big screen!