Chapter 9: Alcohol
Alcohol is a central nervous system depressant and the world's most important psychoactive drug. Alcohol is made through the action of yeasts on sugar, a process known as fermentation. Distillation is used to increase the alcohol content of a beverage. The proof value is an indication of the alcohol content of a distilled beverage; it is equal to twice the percentage of alcohol by weight, meaning that 90-proof whiskey is 45 percent alcohol.
Beer, wine, and distilled spirits are three major types of alcoholic beverages. Beer is made using cereal grains, barley malt, and hops. Wine is made from fermented grapes, while many distilled spirits are mixtures of grain neutral spirits, water, and specific flavoring agents. A 12-ounce beer, 4 ounces of wine, and 1 ounce of 100-proof spirits all have the same amount of pure alcohol and are counted as one drink.
Alcohol use was common in early America and it was not until the early nineteenth century that reformers first proposed temperate use of alcoholic beverages. States began passing prohibition laws in 1851, which were followed by national prohibition in 1920. During Prohibition, people continued to buy and consume alcohol illegally and organized crime became more profitable. However, alcohol dependence and alcohol-related deaths declined. After prohibition was repealed in 1933, per capita consumption of alcohol slowly returned to pre-Prohibition levels.
Alcohol use in the United States varies widely by gender, age, and other factors. Men are more likely than women to be heavy drinkers and college students are more likely to drink than others of the same age. Overall, about one-third of Americans abstain and about 10 percent of those who do drink consume half of all the alcohol consumed in the United States.
Alcohol is absorbed primarily in the small intestine and it is distributed throughout body fluids. Alcohol is metabolized by the liver at a constant rate of about one-quarter of an ounce per hour. Women tend to be more affected than men by a given amount of alcohol because they usually weigh less and have more body fat; there are also gender differences in the activity of an alcohol-metabolizing enzyme in the stomach.
Alcohol acts on the body as a depressant, possibly by affecting several neurotransmitters, especially GABA. Blood alcohol concentration determines its effects on the body. At low levels, it reduces anxiety and improves mood, while at higher levels, it seriously impacts physical and intellectual functioning. Alcohol tends to increase the user's focus on the "here and now," a kind of alcohol myopia that leads to very poor decision making. Drunk driving crashes and fatalities are a serious problem, and alcohol use is statistically related to homicide, assault, date rape, family violence and suicide. Alcohol use appears to enhance interest in sex, but it impairs physiological arousal in both men and women.
Drinking too much in a short period of time can cause potentially life threatening acute physiological toxicity and it nearly always causes the unpleasant collection of symptoms known as a hangover. Longer-term risks of chronic alcohol use include brain damage, serious liver disease, immune system impairment and increased risk of heart disease, cancer and stroke. Withdrawal from heavy alcohol use can also be life threatening. Drinking by pregnant women can cause fetal alcohol syndrome, characterized by physical and behavioral abnormalities.
The notion that alcohol dependence is a disease in its own right was first popularized in the 1940s and 50s by Alcoholics Anonymous. The APA's Diagnostic and Statistical Manual of Mental Disorders defines alcohol abuse as continued use of alcohol despite knowledge of having persistent problems caused by alcohol. Alcohol dependence involves more serious psychosocial effects and includes physiological tolerance and withdrawal among the possible symptoms. Potential underlying causes of alcohol dependence are under study and may include cognitive and genetic factors.