"Caffeine"

This was a particularly enlightening, informative and well-written article
which concludes that caffeine can be both physically and psychologically
addictive.  The American Psychiatric Association has 4 criteria to meet in
order to declare drug dependence: "withdrawal symptoms, development of
tolerance, use of substance even if it causes mental/medical problems, and
repeated unsuccessful attempts at quitting."

When one considers the numbers of regular coffee drinkers in the world,
many people would be somewhat agitated without their morning cup, and most
feel they need the stimulation of caffeine, but they cannot be considered
"drug addicts."  As the NYT article summarizes:

"The researchers also stressed that the finding should not be misconstrued
to diminish the dangers or smoking, alcohol and ilicit drug use....by
comparison...
caffeine is extremeley benign."

This brings up several social questions about drug use.  What drugs should
be legalized?  Does wide-spread use mandate legalization?  Should caffeine
levels  in coffee be regulated?  It's impossible to say.  People metabolize
caffeine at very different rates, ingest in tremendously varying amounts
and differ in terms of required "dosage."  Unlike many other addictive
agents, caffeine does not have much potential for abuse, and therefore does
not pose a serious social problem.  If used in safe levels, people's own
bodies will tell them whether or not they need that extra cup of coffee or
a single or double espresso.

Researchers performed blind experiments in second part, to "eliminate the
possibility that caffeine addiction is imaginary."  Of those receiving the
"dummy" (placebo) pill, most were "functionally impaired for a day and a
half."  The article goes on to describe various other changes in lifestyle
people underwent, and what one pregnant woman did to get her daily fix(!)

Of the 99 subjects, 16 were diagnosed as caffeine dependent.  Thus, about
1/6 regular caffeine "users" are considered addicted.  I predicted a
greater percentage, say 25-30%, but perhaps it's the defining criteria
which are very different than the general population's definition.

All in all, a very interesting look at caffeine, its effects, usage and
withdrawal effects.  When we consider just how widespread caffeine use
really is, it is enough to make one pause and think: "why do we need it?"
Is it the mass-rush of fast-paced society or something we have yet to
discover?

The subjects in that the researchers used were volunteers.  What kind of
bias does this present?