| Caffeine: An Introduction Approximately 90% of Americans consume caffeine in one form or another every day. More than half of all American adults consume more than 300 milligrams of caffeine per day, making it America's most popular drug by far. Caffeine is a chemical compound comprised of hydrogen, nitrogen, carbon and oxygen. Chemically and medically it is known as trimethylxanthine, and the chemical formula is C8H10N4O2. When isolated in pure form, caffeine is a white crystalline powder that tastes very bitter. The chief source of pure caffeine is the process of decaffeinating coffee and tea but caffeine can also be found in drinks, foods and pills, coffee beans, tea leaves, cacao beans and some over the counter medications such as alertness aids and aspirin compounds. Medically, caffeine is useful as a cardiac stimulant and also as a mild diuretic (it increases urine production). Recreationally, it is used to boost energy and heightened alertness. In laboratory tests caffeine has been shown to improve the performance of simple, familiar, routine tasks and impair the accomplishment of complex, novel, unpracticed tasks. A number of studies have found that people who drink at least two portions of caffeinated beverages a day report improved moods, a better social disposition, more self-confidence and energy. In a series of studies on caffeine and its effects on memory, results showed that while coffee helps people to feel less drowsy and fatigued and allows them to perform more effectivley on manual or perfunctory tasks such as typing or calculating, it does not significantly alter numerical reasoning, short term memory or verbal fluency. In other words, caffeine helps you to stay away, but it will not necessarily improve your intellectual skills. As for caffeine's correlation with anxiety, restlessness, agitation, trepidation, studies have shown that only excessive caffeine use produces anxiety. Physical Dependence Caffeine is an addictive drug. Among its many actions, it operates using the same mechanisms that amphetamines, cocaine and heroin use to stimulate the brain. On a spectrum, caffeine's effects are more mild than amphetamines, cocaine and heroin, but it is manipulating the same channels and that is one of the things that gives caffeine its addictive qualities. As a water soluble molecule, it passes easily through all cell membranes and is quickly absorbed from the stomach and intestines into the blood stream, which then gets carried to all the organs. This means, that after you finish your cup of coffee or tea, caffeine will be present in virtually every cell of your body. Caffeine's stimulating effects largely depend on its power to infiltrate the central nervous system. The maximum concentrations of caffeine in the body, including in the blood circulating in the brain that is responsible for caffeine's major stimulating effects, is typically attained within an hour after consumption of a cup of coffee or tea. It is important to remember that the concentration of caffeine in any person's body is a function not only of the amount of caffeine consumed but of the person's body weight. Caffeine and most other chemical compounds you ingest ultimately make their way to the liver; there it is metabolized or converted into secondary products called metabolites which are finally excreted in teh urine. More than 98% of the caffeine you consume is converted by the body in this way, leaving the remainder to pass through your system unchanged. Caffeine increases energy, improves mood and enhances the ability to think clearly for most people. It works by producing an effect on the cardiovascular, respiratory, renal and central and peripheral nervous systems. There are a few theories surrounding caffeine's mechanism of action. Calcium Mobility Theory: Caffeine influences the body's response to neutrotransmitters through affecting the output of neuromediators which indirectly increases the influx of calcium ions into the cells adn therefore increases the force of contraction of the heart muscles Phosphodiesterase Inhibition: The human body stores energy in the muscles in the form of sugars called glycogens. When you need a burst of energy, glycogen is released and burned as fuel. In the 1950s, researchers disocvered a hormone called cAMP (cyclic Adenosine Monophosphate) mediates the actions of many neurotransmitters and hormones of the nervous system. It is believed that caffeine may trigger cAMP to regular glycogen. Adenosine Blockage: Adenosine is a neuromodulator with mood depressing, hypnotic and anticonvulsant properties and tends to induce hypotension, descreases the rate of spontaneous nerve cell firing. IT is believed that caffeine's mechanism of action acts as a competitive antagonist of adenosins and achieves most of its stimulant effects by blocking the uptake and actions of Adenosine. Caffeine supports a physical addiction or dependence, as proved by the withdrawal symptoms associated with its abrupt discontinuation. According to most scientific literature, coffee is among a group of substances that contain a psychoactive drug that produces a physical dependence. It also has additional characteristics in common with drugs that support a clinical dependence syndrome. These characteristics include the ability to improve mood, self-confidence, energy. As early as 1893, N. Bridge reported on a series of patients presenting a variety of symptoms he attributed to the cessation of coffee or tea. Some of the most common symptoms of caffine withdrawal include headaches, sleepiness, drowsiness, impaired concentration, decreased motivation for work, irritability, decreased sociability, muscle aches and stiffness, hot or cold spels, nausea or vomiting, blurred visions, depression, anxiety and impaired psychomotor performance. Roland Griffiths study (1986) found that caffeine withdrawal generally begins Caffeine Intoxication Most who consume coffee, tea and cola never entertain the association between caffeine and drug use. In fact, the MSN-IV includes an entry for "caffeine intoxication" which it describes as an acute drug overdose condition occurring after the ingestion of a large amount of caffeine OR as a chronic condition otherwise known as "caffeinism" or "caffeism" associated with the regular consumption of large amounts of caffeine. Caffeine intoxication has been known in medical literature since the middle 1800s. Unknown to the typical coffee or tea drinker, there exists an entire subculture that expressly employs caffeine as a drug to get high. Caffeinism has been observed to be related to schizophrenic behaviour and delirium. However, excessive caffeine consumption can kill you. The value generally accepted for a fatal overdose is about 10 grams for the average adult, or, the equivalent of 100 cups of coffee References Weinberg, Alan & Bonnie Bealer. 2001.The World of Caffeine. New York: Routledge | 
