Editing Nitrox (section)

===Nitrogen narcosis===
{{Main|Nitrogen narcosis}}
Controlled tests have not shown breathing nitrox to reduce the effects of nitrogen narcosis, as oxygen seems to have similarly narcotic properties under pressure to nitrogen; thus one should not expect a reduction in narcotic effects due only to the use of nitrox.<ref name="Hesser1978" /><ref name=Brubakk304 /><ref group=note>Oxygen has the potential to be 1.7 times more narcotic than nitrogen – see [[:File:Relative narcotic potency.gif|relevant narcotic potency of gases]].</ref> Nonetheless, there are people in the diving community who insist that they feel reduced narcotic effects at depths breathing nitrox. This may be due to a dissociation of the subjective and behavioural effects of narcosis.<ref name="Hamilton1995" /> Although oxygen appears chemically more narcotic at the surface, relative narcotic effects at depth have never been studied in detail, but it is known that different gases produce different narcotic effects as depth increases. Helium has no narcotic effect, but results in [[high-pressure nervous syndrome|HPNS]] when breathed at high pressures, which does not happen with gases that have greater narcotic potency. However, because of risks associated with [[Nitrox#Oxygen toxicity|oxygen toxicity]], divers do not usually use nitrox at greater depths where more pronounced narcosis symptoms are more likely to occur. For deep diving, [[trimix (breathing gas)|trimix]] or [[heliox]] gases are typically used; these gases contain [[helium]] to reduce the amount of narcotic gases in the mixture.