Really understanding Nitrogen narcosis

I'm not sure if this is what I was taught in OW or whether it is just what friends told me but I was under the impression that Nitrogen narcosis occurs at somewhere around 30m and differs from one individual to another and from one dive to another. So far so good.

But then they also told me that it is mostly limited to a specific depth and if you start experiencing it to simply go a little shallower or a little deeper for it to go away again.

Now that I've done AOW the course material contradicted that notion and affirmed that NN only gets worse the deeper you go. This would make sense to me and I've read up a little more since. From what I understand, every breathing gas (including oxygen) has some level of narcotic effect which increases with the gas' lipophilicity (solubility coeficient) and with the gas' partial pressure. There's no physics that I could find which would suggest that the narcotic effect of any gas will at any stage decrease with an increase of partial pressure.

I'm starting to think that I must have misunderstood what other divers told me or that they were purposefully misleading me so as to sound smart or not to scare me off scuba. Or maybe they just think the narcotic effect decreases as you go a bit deeper because they become more narced so that they don't realise they're narced. I mean we all know when we're a bit tipsy on alcohol but have you ever encountered a staggering drunk admitting to the fact that he's drunk?

Your opinions?

I would think that any instructor teaching would know that the narcotic affect gets worse as you go deeper. So, my assumption would be a misunderstanding or miscommunication. Definitely don't think it was anything intentional.

Certainly the deeper that you go the greater the effect ! ! !

Deefstes:

But then they also told me that it is mostly limited to a specific depth and if you start experiencing it to simply go a little shallower or a little deeper for it to go away again.

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Yes that part is absolutely untrue.

I went once to 47 meter and the dive shop asked me if I felt any narc. I did not....so they asked me how much alcohol I drink usually.
It seems as more you drink regularly as better the brain can handle it, as it is used to negative effects....

Deefstes:

I was under the impression that Nitrogen narcosis occurs at somewhere around 30m

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It starts much shallower, having measurable effects as shallow as 10m, but can become a problem around 30m.

Deefstes:

But then they also told me that it is mostly limited to a specific depth and if you start experiencing it to simply go a little shallower or a little deeper for it to go away again

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Go deeper, it gets worse. Go shallower, it gets better, but does not go away until you reach the surface.

Thanks Walter, that's actually the other thing I wanted to ask in the original post but forgot. You nailed it on the button though.

I was curious, having read a little more on the narcotic effect of gasses (not just Nitrogen). Surely, if the narcotic effect increases with partial pressure, it should be present at low pp's even if not as pronounced. I was speculating whether the narcotic effect of Nitrogen was just not really noticeable or problematic at depths shallower than 30m?

Pi**es me off, I can't get narced no matter how hard I try.

So does everyone else.

The other day, my wife picked up a coke can at about 110 fsw, and thought it was something special. Once she got back to about 80 fsw, she looked at it like "what the %$#& am I doing with this thing?". She said she didn't feel narc'd, but obviously she was. I don't think I've ever really felt narcosis, but I know it has affected me when I'm below about 90 fsw, 'cause I feel really at home down there and get depressed when it's time to go. EVERYONE gets narc'd, but it just affects us all differently each day on every dive. Trust me, it DOES NOT go away if you go deeper, only if you ascend, and it's not completly gone untill you surface. Just my 2 psi.