FoundationalConceptsNeuroscience

from the transformation of sugars found in plants. The transforma-
tion is accomplished by the metabolic action of fermentation carried
out by yeast cells. The world’s enormously diverse collection of alco-
holic beverages is produced from a variety of different plants and may
be additionally flavored by an even larger variety of plants containing
countless interesting and exotic molecules. All alcoholic beverages
contain ethyl alcohol as the primary psychoactive component.
Number three would be nicotine, by virtue of its identification
as the principal psychoactive chemical in the tobacco plant. While
caffeine and ethanol are consumed via oral ingestion into the diges-
tive system, tobacco is commonly used by burning the dried leaves of
the plant and inhaling the smoke, containing vaporized nicotine and
other chemicals.
The fourth most widely used psychoactive drug in the world is not
one most people correctly guess. It is the areca nut, also known as
the betel nut, the seed of the palm tree Areca catechu native to India,
Southeast Asia, and the southwestern Pacific Oceana region. As with
any plant material, there are many, many molecular constituents, and
many of these have potential physiological activity. In the areca nut,
the molecule arecoline has been identified as the chemical constituent
perhaps most responsible for the physiological effects of the nut, a
combination of relaxation and mental stimulation.
While the areca nut is not widely known in the Western hemisphere,
many millions of people in India, Southeast Asia, and Oceana ingest it
on a daily basis for its psychoactive effects. That makes it very likely to
be number four.