Caffeine is the most widely used psychoactive drug today. According to the latest coffee consumption statistics, coffee is the most popular beverage worldwide with over 400 billion cups consumed each year. Caffeine comes from a chemical classification of drugs called xanthines and is a central nervous system (CNS) stimulant. Caffeine is found in traditional forms such as coffee, tea, and chocolate, but it has also been synthesized. It comes in many different forms such as soft drinks, anti-sleeping over-the-counter medications, and energy drinks. Caffeine is also found in prescription medication to treat headaches and bronchial constriction.


Caffeine had been used in various cultures long before it appeared in written records. The ancient Chinese may have used tea as far back as 2737 B.C.E. Around 800 C.E., ...

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