Ethyl alcohol, or ethanol, is the most commonly used drug in the world. Pharmacologically, alcohol is classified as a central nervous system depressant. Like other depressants, in small doses alcohol slows heart rate and respiration, decreases muscular coordination and energy, dulls the senses, and lowers inhibitions—resulting in feelings of relaxation and greater sociability. Large amounts of alcohol can result in depression of the various body systems, resulting in coma or death. The immediate physical effects of alcohol depend on the amount and frequency of drinking, while the mental and emotional effects are influenced by the mood of the drinker and the setting in which drinking takes place.
Two physical effects resulting from prolonged, heavy alcohol use include tolerance and withdrawal. Alcohol tolerance refers to the need for increased amounts of alcohol to achieve the same level of intoxication. For example, five or six drinks may be needed to achieve the same effects produced by one or two drinks when the individual first began drinking. Alcohol withdrawal, on the other hand, refers to a number of physical and psychological reactions an individual experiences when significantly reducing or stopping prolonged heavy drinking. Symptoms of withdrawal include nausea, vomiting, anxiety, and hand tremors.
An interaction of biological, psychological, and environmental factors come into play in the development of drinking behaviors and problems. For example, some individuals may be genetically predisposed to alcohol problems, but whether or not they actually experience negative alcohol consequences will also depend upon their immediate social and physical surroundings, such as family drinking patterns and alcohol availability, as well as their drinking habits.
CHUDLEY E. WERCH, The Gale Group Inc., Macmillan Reference USA, New York,