caffeine (kăfēn´), odorless, slightly bitter alkaloid found in coffee, tea, kola nuts (see cola), ilex plants (the source of the Latin American drink maté), and, in small amounts, in cocoa (see cacao). It can also be prepared synthetically from uric acid. While relatively harmless, it is the most commonly used mind-altering drug in the world. When used in moderation, caffeine acts as a mild stimulant to the nervous system, blocking the neurotransmitter adenosine and resulting in a feeling of well-being and alertness. It increases the heart rate, blood pressure, and urination and stimulates secretion of stomach acids; excessive intake can result in restlessness, insomnia, and heart irregularities. The effects of caffeine vary from person to person, as people excrete it at different rates. Physical dependence and unpleasant symptoms upon withdrawal (headache, fatigue, depression) are common in regular caffeine users.

See B. A Weinberg and B. K. Bealer, The World of Caffeine (2001).

The Columbia Encyclopedia, 6th ed. Copyright© 2018, The Columbia University Press.

Caffeine: Selected full-text books and articles

Caffeine: More Than Just a Pick-Me-Up? By Schardt, David Nutrition Action Healthletter, Vol. 44, No. 1, January-February 2017
Caffeine: Don't Let Your Pick-Me-Up Drag You Down By McGill, Natalie The Nation's Health, Vol. 43, No. 10, January 2014
Buzz: The Science and Lore of Alcohol and Caffeine By Stephen Braun Oxford University Press, 1996
The Cultural History of Plants By Ghillean Prance; Mark Nesbitt Routledge, 2005
Librarian's tip: Chap. 10 "Caffeine, Alcohol, and Sweeteners"
Effects of Caffeine and Coffee on Females By Georgiev, Krum G.; Beagle, Martha E.; McCheng, Jeffrey VAHPERD Journal, Vol. 29, No. 2, Fall 2007
Caffeine Consumption Patterns and Beliefs of College Freshmen By McIlvain, Gary E.; Noland, Melody P.; Bickel, Robert American Journal of Health Education, Vol. 42, No. 4, July-August 2011
Peer-reviewed publications on Questia are publications containing articles which were subject to evaluation for accuracy and substance by professional peers of the article's author(s).
Caffeine-Induced Psychiatric Disorders By Torres, Francis M Journal of Continuing Education Topics & Issues, Vol. 11, No. 2, April 2009
The Essence of Commodification: Caffeine Dependencies in the Early Modern World By Jamieson, Ross W Journal of Social History, Vol. 35, No. 2, Winter 2001
Engineering Psychophysiology: Issues and Applications By Richard W. Backs; Wolfram Boucsein Lawrence Erlbaum Associates, 2000
Librarian's tip: Chap. 9 "The Effect of Naps and Caffeine on Alertness during Sleep Loss and Nocturnal Periods"
Drugs and Society By Wendy Horobin Marshall Cavendish Reference, vol.1, 2006
Librarian's tip: "Caffeine" begins on p. 152
Biofeedback: A Practitioner's Guide By Mark S. Schwartz; Frank Andrasik Guilford Press, 2003
Librarian's tip: "Caffeine" begins on p. 192
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