I know about Nitrogen Narcosis from diving too. It is always the first thing that comes to mind when people mention nitrogen in the lines. Is this the cause for heroin beer, I don't know, but definitely something to think about.
I decided to look it up on wikipedia:
"
Nitrogen narcosis or
inert gas narcosis is a reversible alteration in
consciousness producing a state similar to alcohol intoxication in
SCUBA divers at depths beyond 30m.
Jacques Cousteau famously described it as the "rapture of the deep". Its precise mechanism is not well understood, but it appears to be a direct effect of high nitrogen pressure on nerve transmission. While it was first observed with nitrogen (in air), other gases including
argon and
hydrogen also cause very similar effects under high enough pressure.
Xenon is actually a usable anaesthetic at atmospheric pressure, though it is too expensive to be used in practice.
The onset is hard to recognize, its severity is unpredictable, and it can kill, from its own toxic effect or due to the resulting illogical behaviour. However the cure for nitrogen narcosis is a simple one, as effects disappear upon ascending to shallower waters."
Also found this further on in the definition, hmmm
"Experts recommend total abstinence at least 24 hours before diving, and longer for heavy drinking.
Alcohol combined with nitrogen is likely to bring on a far more serious case of narcosis. This is yet another good reason for not drinking and diving."
Could be a possibility, but who knows?