Hi David, 
Wikipedia defines addiction as: 
Addiction is the continued use of a mood altering substance or behavior
despite adverse dependency consequences, or a neurological impairment
leading to such behaviors. (http://en.wikipedia.org/wiki/Addiction)

I suppose that you could argue that oxygen deprivation causes a definite and
dramatic but short-lived mood disturbance, but the key difference I see is
that while oxygen is critically necessary to all human life, addictive
substances are only necessary to life in some people and under a few special
circumstances. These might include, but are not limited to mitigating severe
pain, the need for sedation for surgery, or sometimes, in the context of an
established addiction. The mild addictions I was talking about, with respect
to bata casomorphins 5 and 7, seem to have several predisposing facets:

We are born with a leaky gut. This means that during the first months of
life human infants lack an effective intestinal barrier in the gut. This
barrier slowly develops during those early months when infants are mostly
reliant on breast milk. In those early months, the sedating effect of those
opioids might well provide a selective advantage. 

The casomorphins in breast milk behave like morphine. They attach to the
same receptors and they have a sedating effect. The children I have
observed, when they had a clean diaper, usually fall asleep while suckling
or almost immediately after being fed. It seems to me that when hiding from
predators, it would be very useful to be able to quickly sedate an infant in
order to reduce the risk of detection.        

Weaning is a difficult time because infants crave breast milk. However, the
gradual increase in integrity of the gut barrier probably produces a gradual
reduction in the casomorphins that reach the bloodstream, and then, the
brain. So we have a built-in weaning mechanism that may persist even up to 3
or 4 years of age. 

This elegant adaptation reflects the intricate dance between our environment
and our hominid or early human forebears. Perhaps suckling at the breast
predisposes to addiction in later life.  The various social lubricants such
as alcohol, nicotine, and even weed, may all be ingested in a similar
fashion. These socially acceptable substances often involve a suckling
action.  Whether a joint, a cigarette, a cigar, a pipe, a bottle, a straw,
or a can, these addictive substances can all be ingested by the same
suckling action that was imprinted on our brains from the time of each of
our births. 

I am awed by each new insight into natural selection but I really don't
think that I misused the term addiction. Please explain how it became a
"throw-away word" in my usage of it.
best wishes, 
Ron  

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++

Addiction seems like it has become a throw-away word. Everything gets turned
into an addiction. The biggest addiction seems to be the drug oxygen. We are
all addicted to oxygen. Just look at the withdrawal symptoms when we run out
of our oxygen fix.
-David H