The analysis I read said that O2 is actually more narcotic than N2, but because some of it is metabolized, that brings its overall effect to be very close to that of N2.
Archer are you talking about narcotic in the recreational range or the tech depth ranges. I ask this because it is (I assume) true tat O2 is narcotic however IF it does not become disabling narcotic till ie 200 ft then it is a non worry issue at <100 ft. Millions of divers use nitrox to 140 all the time and if you dive air you are diving nitrox by definition. folks are deep diving air to 200 ft. At some point all gassed take their toll as the PP of that gas increases. Our bodies are geared to run on PPO2 of .21 +/- yet we by application push it to 1.4 and above without consequence. Also time has to be a factor in the exposure at those PPO2's. A hospital bed with a O2 tent will get you after a period of time and there are protocols to prevent that. In diving we use trimix to manage those factors. We insert a replacement gas that is not narcotic in the depth ranges we are using them at. Ill make this up but He may be narcotic below 1000 ft, so at 200 ft its a non issue.