Caffeine Addiction Caffeine Addiction Technically, a drug is a chemical substance used to prevent or cure disease or to enhance a person's physical or mental welfare. In fact, people use caffeine for all of these purposes and caffeine can do all of these things, but usually in a very limited way.
Caffeine is the most popular drug in the world.
Though caffeine is a chemical used for both medical and nonmedical reasons, most often it is used non-medically for its stimulating effect on mood and behavior. Heroin, cocaine, marijuana, nicotine, alcohol, and caffeine are all psychoactive drugs. It is moderately soluble in water at body temperature and is easily soluble in boiling water. After coffee and tea, the next most important source is soft drinks, and the next, cocoa and chocolate.