Introduction

Alcohol has been used for centuries in social, medical, cultural, and religious settings. Most Americans believe alcohol can be used responsibly by adults for social and religious purposes. However, alcohol can also be used to excess resulting in health, social, legal, and other problems. Students may receive conflicting messages about alcohol from the news media, school, their friends, and their parents. On the one hand, they hear that moderate alcohol use is acceptable, and in some instances may actually be good for your health; on the other hand, they are told that alcohol is a drug that requires abstinence until age 21. In addition, advertisements and media images often present alcohol as a means to success and an enjoyable life. These conflicting messages, combined with misunderstandings and misinformation, do not help students make responsible decisions about alcohol use.

Figure 1

Alcohol has been part of societies for thousands of years, as shown by this representation of the ancient Greek god of grape growing and wines, Bacchus.

Statistics indicate that many adolescents begin consuming alcohol at an early age. In 1997, 26 percent of eighth graders, 40 percent of 10th graders, and 51 percent of 12th graders reported consuming alcohol within the month prior to the survey.⁴³ In addition, 16 percent of eighth graders reported binge drinking within the two weeks leading up to the survey. The effects of adolescent drinking involve both health- and safety-related problems, including auto crashes, domestic violence, and suicide. Alcohol abuse among teenagers may also be related to behavioral problems linked to impulsiveness and sensation seeking.⁵⁵ Youth alcohol-use data indicate that the earlier an individual begins drinking, the greater his or her risk of developing alcohol-use problems in the future. Individuals who begin drinking before age 15 are four times more likely to develop alcohol dependence during their lifetimes than are those who begin drinking at age 21.^{24, 25}

The earlier an individual begins drinking, the greater his or her risk of developing alcohol-related problems in the future.

Dr. Enoch Gordis, former Director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), has written, "Although alcohol is sometimes referred to as a `gateway drug' for youth because its use often precedes the use of other illicit substances, this terminology is counterproductive; youth drinking requires significant attention, not because of what it leads to, but because of the extensive human and economic impact of alcohol use by this vulnerable population."⁴³

The purpose of this supplement is to present students with the opportunity to learn about the science underlying the effects of alcohol on human biology and behavior through a series of inquiry-based classroom lessons. Young people are natural scientists. They have a curiosity about the world around them and about themselves as individuals. Since they have little in the way of life experiences, many young people tend to view themselves as nearly invincible. Consequently, when adults caution them against engaging in risky behaviors such as drinking alcohol, some don't listen. They feel that such warnings aren't for them and apply only to those less grown up than themselves.

The aim of this supplement is to give students the opportunity to construct their own understanding about alcohol and its attendant risks. In addition, the inquiry-based lessons are designed to help students hone their critical-thinking skills. With enhanced understanding and skills, they will be better prepared to make informed decisions about real-life situations involving alcohol use.

Alcohol Use, Abuse, and Alcoholism: Definitions

In any discussion of alcohol use, it is crucial to begin with a clear understanding of terms. For the purposes of this module, we define alcohol use by adults as the consumption of alcohol for social or religious purposes without demonstrating the characteristics of alcohol abuse or alcoholism (see Tables 1 and 2). Alcohol abuse is defined as the continued use of alcohol despite the development of social, legal, or health problems. It is important to note that any alcohol use by underage youth is considered to be alcohol abuse.

Table 1

Characteristics of Alcohol Abuse.

Table 2

Characteristics of Alcoholism.

In contrast, alcoholism, also known as alcohol dependence syndrome or alcohol addiction, is a chronic disease involving a strong need to drink, the inability to stop drinking, the occurrence of withdrawal symptoms, and tolerance (see Table 2). Alcoholism is often progressive.

Any alcohol use by underage youth is considered to be alcohol abuse.

Alcohol abuse is not equivalent to alcoholism. A person who abuses alcohol may drink excessive amounts but does not experience an alcoholic individual's intense cravings or severe withdrawal symptoms (physical dependence) when drinking stops. Susceptibility factors that contribute to alcoholism are genetic, environmental, and psychosocial. Thus, while not all people who abuse alcohol become alcoholics, those with genetic susceptibility factors who place themselves in environments that encourage drinking put themselves at risk for developing alcoholism.

The definitions of alcohol abuse and alcoholism described above do not directly apply to youth drinking. As previously noted, any alcohol drinking by underage youth is considered to be alcohol abuse. Youth who abuse alcohol typically do so by drinking often,⁴³ or engaging in binge drinking, which is commonly defined as drinking five or more drinks in a row. Such drinking patterns put youth at increased risk for developing alcoholism later in life. Research suggests that separate criteria may be needed to distinguish between alcohol abuse and alcoholism in youth as compared with adults.^{34, 43} Table 3 lists some of the risk factors associated with youth drinking.

Table 3

Risk Factors for Youth Drinking.

Misconceptions about Alcohol Use, Abuse, and Alcoholism

Generally, textbooks for middle school students present little, if any, scientific information on how alcohol affects cell function and animal behavior. If the subject is covered at all, it is likely done in a health class, or possibly in a driver's education class. Much of what students know, or think they know, comes through family, peers, the media, and personal experimentation. Very often this information is characterized by errors, half-truths, and folk wisdom. Students need to understand the changes that occur in their minds and bodies when they drink alcohol. They also need to understand that if they choose to drink, there can be both short-term (acute) and long-term (chronic) consequences, even with moderate levels of drinking. The materials contained in this curriculum supplement, Understanding Alcohol: Investigations into Biology and Behavior, should at least help correct the following misconceptions.

Even moderate levels of alcohol use can lead to both short-term and long-term consequences.

Misconception 6: Alcohol's effects are only temporary

The adult body can process approximately one drink per hour. A drink, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA), is one 12-ounce bottle of wine cooler or beer, one 5-ounce glass of wine, or 1.5 ounces of 80-proof distilled liquor.⁴² A significant portion of the societal costs of alcohol use (for example, falls, automobile crashes, and violence) is due to acute effects. Alcohol users and abusers, as well as alcoholics, can suffer injuries related to the acute effects of alcohol. Although the acute effects of alcohol last only a short time, chronic long-term effects can develop and persist. Adolescents and adults who drink excessive amounts of alcohol may be causing chronic alterations to their brains. A recent study provides evidence that heavy drinking among teenagers can impair brain function.⁷ It is not yet known if these effects are reversible.

Figure 2

A drink can be one 12-ounce beer, one 5-ounce glass of wine, or 1.5 ounces of 80-proof distilled liquor.

Misconception 8: Alcoholism can be cured by behavioral programs such as Alcoholics Anonymous

Alcoholism, at present, has no known cure. However, as with other chronic diseases, such as diabetes or heart disease, alcoholism can be controlled effectively using behavioral therapies, with or without pharmacological therapies. For such treatments to be effective, however, the patient must be willing to make significant and permanent lifestyle changes. People being treated for alcoholism often experience one or more episodes of relapse. An important aspect of behavioral therapy is to help patients deal with such relapses and motivate them to continue their efforts to remain sober.

Figure 3

Behavioral therapy helps patients deal with relapse and motivates them to continue with their efforts to remain sober.

Animals as Research Models

Much of the research into the effects of alcohol on humans uses animals. Scientists use animals when the use of humans is either impractical or unethical. For example, when scientists investigate fetal alcohol syndrome, they cannot give alcohol to pregnant women but they can give alcohol to pregnant animals.

Scientific research with animals has contributed to many important advances in scientific and medical knowledge. When using animal models, scientists first must choose an animal appropriate to their research. Scientists studying genetics often use fruit flies (Drosophila melanogaster) because they have a short generation time. However, fruit flies are not a good model to use when investigating aspects of mammalian physiology. In such cases, a mouse or rat is preferred.

Figure 4

Mice are a useful model for studying the effects of alcohol.

Animal models do have their drawbacks. Some animals are difficult or expensive to maintain. Consequently, many scientists try to develop nonanimal models using cell cultures or computer simulations. Unfortunately, such models usually fail to duplicate the complexity of the animal or human body. Medical and scientific research will continue to depend on animal models for the foreseeable future (see The Use of Animals in Scientific Research below).

Alcohol: Pharmacokinetics

Because of its legal status and prevalence in society, alcohol should be considered apart from other drugs. The term drug is not always easy to define. In a medical context, a drug may be defined as any substance used in the diagnosis, prevention, treatment, or cure of a disease. In an abuse context, a drug may be described as any substance that alters consciousness and may be habit forming. According to these definitions, alcohol is classified as a drug in the context of abuse.

Alcohol is classified as a drug in the context of abuse.

The alcohol contained in alcoholic beverages is called ethanol. Ethanol is a small molecule having a 2-carbon (C) backbone with 5 attached hydrogens (H) and a hydroxyl (OH) group at one end. This terminal hydroxyl group is characteristic of an alcohol (Figure 5). Ethanol is formed by a natural conversion process called fermentation where yeast, a fungus, converts sugar into alcohol and carbon dioxide. The natural sugars found in fruit, berries, and malted grains are fermented to produce beer and wine. Liquors, however, are produced through the process of distillation.

Figure 5

Chemical structure of ethanol.

Box

The Use of Animals in Scientific Research.

Measurement of blood alcohol concentration (BAC)

Metabolism refers to the process by which the body breaks down food to extract energy from it. With respect to alcohol, metabolism refers to the transformation of ethanol to acetaldehyde and other products. The primary site of alcohol metabolism is the liver. Only a tiny fraction (less than 10 percent) of the alcohol consumed is not metabolized and is excreted from the body in breath, sweat, and urine.⁶ This process of metabolism and excretion is known as elimination. The concentration of alcohol in breath and urine mirrors the concentration of alcohol in blood. This means that alcohol in breath can be detected, measured, and used to calculate a person's blood alcohol concentration (BAC). The BAC calculation is the standard means of determining the extent of a person's alcohol impairment.

BAC, although expressed as a percentage when a unit of measure is shown, is actually a weight-per-volume measurement: grams of ethanol per 100 milliliters, or deciliter, of blood. The calculation of an individual's BAC depends partially on the total amount of water in the body. For example, males average 58 percent of their total body weight as water, while females average 49 percent.³⁸ Other factors important to calculating BAC are the amount of alcohol consumed and the burnoff, or rate at which the alcohol is metabolized.

The concentration of alcohol in the breath and urine mirrors the concentration of alcohol in the blood. This means that alcohol in breath can be detected, measured, and used to calculate a person's blood alcohol concentration (BAC).

In a practical sense, the only factor influencing the BAC calculation likely to be known with great precision is the amount of alcohol consumed. The total body water and burnoff are themselves influenced by several factors. Total body water is a function not only of a person's gender, but also of his or her weight and body type. Alcohol metabolism (burnoff) also varies among people. Heavy drinkers, for example, can have elevated rates of alcohol metabolism due to higher-than-normal concentrations of alcohol-metabolizing enzymes. Higher levels of these enzymes increase the burnoff. The average metabolism for a moderate drinker results in a decline in BAC of about 0.017 per hour, while a heavy drinker may have a decrease of 0.020 per hour. The range of metabolism rate per hour is from above 0.040 to below 0.010.³⁸ For more detailed descriptions of BAC effects on the brain and body, see 6.1 Alcohol and the brain and 6.2 Alcohol and body systems, as well as Table 4, on page 38.

Table 4

Progressive Effects of Alcohol.

Factors affecting alcohol absorption and elimination

Humans vary widely in their ability to absorb and eliminate alcohol. This section describes some of the most important factors that influence how quickly alcohol is absorbed into the blood.

Food

Absorption of alcohol is faster when the stomach is empty; the empty stomach allows rapid passage of the alcohol into the small intestine, where absorption is most efficient. This means that the apparent sobering effect of eating prior to alcohol consumption is due to a delay in stomach emptying. A recent study showed that people who drank alcohol after a meal that included protein, fat, and carbohydrates absorbed alcohol nearly three times more slowly than when they drank alcohol on an empty stomach (see Figure 6). The rate of alcohol absorption depends not only on the presence or absence of food, but also on the type of food present. Foods with a higher fat content require more time to leave the stomach; consequently, eating fatty foods will allow alcohol absorption to take place over a longer time.

Figure 6

The effect of food on blood alcohol concentration. The graph shows BAC after a person drank alcohol following an overnight fast (solid line) and immediately after breakfast (dotted line).

Although alcohol's effects are delayed by the presence of food in the stomach, they are not prevented. Individuals may drink too much alcohol in a short time, believing that it isn't having an effect. Only after the delay in the absorption and elimination of the alcohol is the impact of their drinking felt, perhaps with disastrous consequences.

Body weight and build

Greater body weight provides a greater volume in which alcohol can be distributed. This means a larger person will be less affected by a given amount of alcohol than a smaller person would be. Alcohol is more soluble in water than in fat. This means that tissues rich in water, like muscle, take up more alcohol than do tissues rich in fat. A leaner person with a greater muscle mass (and less fat) provides a larger volume for alcohol to be distributed in compared with a person who weighs the same but has a higher percentage of body fat. In summary, if you compare two people of equal size but who differ in amount of body fat, the effects of alcohol will be different in them. The person with low body fat will be affected less than the person with a higher level of body fat.

Gender

Females, on average, have a smaller body mass and a higher proportion of body fat than do males. These characteristics mean that, on average, females have a lower proportion of total body water in which to distribute alcohol. Females also may have a lower activity of the alcohol-metabolizing enzyme alcohol dehydrogenase (ADH) in the stomach; therefore, more of the ingested alcohol reaches the blood. These factors mean that females generally exhibit higher BACs than do males after consuming the same amount of alcohol and are more vulnerable to alcohol's effects. Females are also more susceptible than males to alcoholic liver disease, heart muscle damage, and brain damage.⁴⁵

Alcohol metabolism

The primary place where alcohol is metabolized is the liver. Liver cells contain ADH, which converts alcohol to acetaldehyde. Other enzymes in turn convert the acetaldehyde to carbon dioxide and water, which are excreted from the body. If the rate of alcohol consumption exceeds the rate at which the alcohol can be metabolized, then the concentration of alcohol in the blood rises and the individual may become intoxicated.

The effects of absorption, distribution, and elimination combine to produce a characteristic blood alcohol curve (Figure 8). Immediately after a person drinks alcohol, the BAC rises sharply during the absorption phase to a maximum that depends on the amount consumed. Typically, the greatest alcohol concentration is reached 45–90 minutes after drinking. BAC then slowly declines due to diffusion of alcohol into the body tissues as part of the distribution phase. Finally, BAC falls more quickly during the elimination phase. Alcohol is removed from the body through the normal routes of excretion as part of this process. During periods of high BAC, about 5 percent of the alcohol is excreted in breath and another 5 percent in urine, with negligible amounts excreted in sweat and feces.

Figure 8

Blood alcohol concentration over time.

Figure 7

Alcohol's effects are influenced by gender, body weight, and body type.

The shape of the blood alcohol curve is influenced by many factors including such variables as body size, gender, build, amount and type of beverage ingested, duration of drinking, fatigue, and the presence and type of food. These variables are also major determinants of the timing and peak of the blood alcohol curve.

Alcohol: Biological Effects

Upon consumption, alcohol is distributed throughout the water-containing portions of the body, affecting primarily those organs having a high water content. One of these is the liver, which is the organ that metabolizes alcohol. Another is the brain, the organ that is the seat of cognition and behavior.

Alcohol and the brain

The brain is composed of billions of nerve cells called neurons. A typical neuron has three important parts (Figure 9). The cell body is responsible for directing all of the neuron's activities. The dendrites are a cluster of small fibers that receive chemical messages from other neurons. The axon is a single, long fiber that transmits messages from the cell body to other neurons or other cells of the body, such as muscle cells.

Figure 9

A typical neuron.

Although the axon of a neuron is extremely close to the dendrites of an adjoining neuron, they do not touch. The tiny amount of space between the neurons is called the synapse. The process by which neurons transmit messages to each other is known as neurotransmission. A message is an electrical impulse in the cell body that moves down the axon toward the synapse. At the synapse, it triggers the release of molecules called neurotransmitters, which diffuse across the synapse and bind to receptor molecules located in the cell membranes of the adjoining neuron's dendrites. The binding of the neurotransmitter either stimulates or inhibits the electrical impulse in the receiving neuron (see Figure 10).

Figure 10

Neurotransmission across a synapse.

There are many types of neurotransmitters in the brain, each with a specific function. The binding of a neurotransmitter to its receptor is specific—that is, a neurotransmitter fits its own receptor much like a key fits only the appropriate lock. Once a neurotransmitter has passed on its message, it is either broken down by an enzyme or reabsorbed by the same neuron that released it.

For many years, scientists thought that alcohol altered the function of neurons in the brain by interacting with fat molecules in the cell membranes. More recently, it has become apparent that alcohol interacts with proteins found in the cell membranes, particularly those involved in neurotransmission. Like other drugs of addiction, alcohol acts via the brain's reward pathway in the limbic system (see "Reward pathway or pleasure circuit," on page 34). However, alcohol is unlike other drugs in that it interacts with multiple systems in the brain, sometimes stimulating and at other times inhibiting neurotransmission.

After drinking a sufficient amount of alcohol, many individuals experience a pleasurable state of mind. This pleasurable sensation leads some individuals to seek repeated exposure to alcohol. If drinking is excessive, it can lead to confusion, loss of coordination, sedation, coma, and even death. Long-term exposure to alcohol can lead to tolerance of its effects and eventually to physical dependence. The term "tolerance" refers to a decrease in brain sensitivity to alcohol following long-term exposure (see 2 Alcohol Use, Abuse, and Alcoholism: Definitions, on page 24, and "Tolerance," on page 34). If alcohol-dependent individuals stop drinking, they experience withdrawal symptoms, which may include tremors, anxiety, sweating, hallucinations, and seizures. The site of action of all these effects is the brain.

The physiological and behavioral changes associated with intoxication reflect the effects of alcohol on various parts of the brain.

Intoxication

The physiological and behavioral changes associated with intoxication reflect the effects of alcohol on various parts of the brain. For example, the loss of coordination observed in intoxicated individuals may result from the effects of alcohol on a portion of the brain called the cerebellum, which functions in the control of movement (see Figure 11). Alcohol-induced memory lapses may result from impairment of the hippocampus, a part of the brain that helps store new memories. Drinking can be sufficiently excessive that death results from suppression of the brainstem activity that controls breathing and circulation.

Figure 11

Regions of the brain affected by alcohol.

Reinforcement

The properties of alcohol that can cause continued drinking, such as its pleasurable and anxiety-reducing effects, are the very ones that contribute to chronic alcohol abuse and alcoholism. This is known as reinforcement. Scientists are currently exploring the brain chemistry involved in reinforcement. Research suggests that specific brain regions, such as the hypothalamus (which is involved in hunger, thirst, and emotions), as well as the amygdala, nucleus accumbens, and prefrontal cortex, play a role in reinforcement. Specific neurotransmitters are also implicated in alcohol's reinforcing effects.

Tolerance

Tolerance refers to the body's ability to adapt to chronic alcohol use. With continued use, the brain becomes less sensitive to alcohol. This means that higher BACs are needed to produce intoxication. Both alcohol abusers and alcoholics can display tolerance. BACs that can render nonabusers unconscious can leave abusers and alcoholics appearing nearly sober.

When alcoholic individuals stop drinking, they may experience severe alcohol cravings, short-term memory loss, disruption of cognitive and motor function, reduced perceptual abilities, and emotional and personality changes.

Chronic alcohol use leads to increased concentrations of the liver enzymes that metabolize alcohol. This allows the liver to break down alcohol more efficiently; therefore, the individual must consume more alcohol to reach a given BAC. There also is a behavioral component to tolerance. Subjected to chronic, excessive alcohol exposure, an individual learns to function under the influence of alcohol. For example, functional tolerance can reduce the impairment that would ordinarily accompany the performance of a task. Individuals may be able to drive home successfully after drinking because the route is familiar and nothing unexpected happens. However, if they encounter a detour or another car unexpectedly darts in front of them, they will be at the same risk for a crash as a driver with the same BAC who is unfamiliar with the route. The increased amounts of alcohol consumed by a person experiencing tolerance can severely damage the body's physiological systems despite their apparent normalcy.

Physical dependence and withdrawal

When alcohol use is stopped, withdrawal symptoms include severe alcohol cravings as well as physical and psychological problems. The biochemical changes associated with withdrawal lead to short-term memory loss, disruption of cognitive and motor function, reduced perceptual abilities, and emotional and personality changes.³ Another consequence of withdrawal is delirium tremens (sometimes referred to as the DTs). Delirium tremens is characterized by severe agitation and hallucinations. The DTs can begin within a couple of days after alcohol consumption has stopped and can last for a week or more. The mechanisms behind tolerance and physical dependence involve relationships among nerve cell membranes, neurotransmitters and their receptors, and the reward pathway. All of these are areas of active research.

Reward pathway or pleasure circuit

The reward pathway is a powerful biological force. Strong motivations such as eating, drinking, and sex can activate neurons that produce and regulate feelings of pleasure. The reward pathway consists of a network of neurons found in the middle of the brain (see Figure 12). When activated by a positive experience, a group of neurons near the top of the brainstem (called the ventral tegmental area) releases the neurotransmitter dopamine. This message is relayed to a structure called the nucleus accumbens (part of the emotional limbic system) and to a related part of the prefrontal cortex, resulting in a pleasurable sensation.

Figure 12

The reward pathway.

The reward pathway can also be activated by a negative experience. Animal studies have shown that concentrations in the brain of a neurotransmitter associated with stress rise sharply during withdrawal from alcohol. The animal is motivated to seek the reward (alcohol) to avoid the pain of withdrawal. A similar process propagates the human cycle of alcohol addiction: individuals are motivated to continue consuming alcohol to avoid the discomfort of withdrawal, even though this behavior maintains addiction.

Alcohol: Behavioral Effects

The brain is the origin of all human behavior, so it is not surprising that exposure to alcohol leads to changes in behavior. As discussed in 6.1 Alcohol and the brain, the human brain has a high water content. Consequently, it is very sensitive to the effects of alcohol consumption. Alcohol induces several behavioral changes because it affects various areas of the brain. For example, the cerebellum (movement), the hippocampus (memory), the ventral tegmental area (reward), and even the brainstem (breathing) are all affected by drinking alcohol.

The short-term behavioral effects of alcohol follow the typical dose-response relationship characteristic of a drug; that is, the greater the dose, the greater the effect [see 5.2 Measurement of blood alcohol concentration (BAC)]. Table 4 shows that increased blood alcohol concentrations lead to changes in personality as well as loss of control over physical functions. An early (and nearly universal) effect of alcohol on personality is the loss of inhibition. Other effects experienced at lower BACs (0.01–0.05) include a sense of well being and lowered alertness. These BAC values also impair thought, judgment, coordination, and concentration in most individuals.

The short-term behavioral effects of alcohol follow the typical dose-response relationship characteristic of a drug; that is, the greater the dose, the greater the effect.

It is easier to predict the physical effects of alcohol than the behavioral ones, especially at BACs in the range of 0.06–0.20. Personality influences behavioral responses. Loss of inhibition combined with additional drinking leads some individuals to become increasingly boisterous while others become withdrawn. Still others become angry and aggressive. Not surprisingly, inappropriate expression of anger and aggression can lead to abusive behavior and violence (see 10.5 Drinking and violence). Excessive drinking may also cause some individuals to experience severe emotional swings and even trigger severe depression. At BACs of 0.21–0.29, loss of muscle control leads most individuals to experience stupor and impaired sensations. Since BACs over 0.30 affect breathing and heart rate, all individuals experiencing this BAC are at risk for unconsciousness, coma, and even death.

Though the behavioral effects of alcohol are unpredictable and vary from one individual to another, a number of factors are known to influence alcohol's effects on behavior. One important factor that influences both personality and susceptibility to alcohol abuse is genetics (see 8.2 Alcoholism and genetics, on page 39). Genetic influences work at both the individual and the population levels. For example, certain genetic variations that exist more often in Chinese and Japanese populations lead to an increased sensitivity to alcohol's effects, which in turn leads to a decreased susceptibility to alcoholism. An individual possessing these genetic variations experiences facial flushing, an elevated heart rate, and a burning sensation in the stomach upon consumption of alcohol. These negative consequences generally deter further alcohol consumption. In other populations, different genetic variations lead to an increased susceptibility to alcoholism. In still other populations, genetics has not been shown to influence an individual's drinking behavior. It is important to remember that an individual cannot control his or her genetic makeup, but being aware of it can help a person decide whether the choice to drink alcohol would be risky.

Drinkers expect to feel and behave in certain ways when drinking. Expectations about drinking can begin at an early age, even before drinking begins.

There are, of course, nongenetic factors that influence drinking behavior. The term expectancy refers to what a person expects will happen in a given drinking situation. Research has shown that drinkers expect to feel and behave in certain ways when drinking. Expectations about drinking can begin at an early age, even before drinking begins.⁴⁸ Students who engage in binge drinking during high school are more likely to do so in college.⁵⁷ Young people are also influenced by their perceptions of how much they think their friends drink. Studies have shown that college students tend to think their friends drink more than they actually do.⁴⁰ This belief can cause them to increase their level of drinking in an effort to "fit in." Other social factors that promote increased alcohol consumption are drinking in groups and serving oneself.^{20, 21}

Alcoholism

Alcoholism treatments

Although it is a chronic disease, alcoholism can be treated successfully. Any successful physiological treatment for alcoholism must also include a psychological component. Similar to other chronic diseases, such as heart disease or diabetes, relapse is common during the course of alcoholism. Thus, successful treatment is defined in terms of recovery, not cure. Research continues to develop both pharmacological and psychosocial (behavioral) therapies for alcoholism.⁵⁴

Any successful physiological treatment for alcoholism must also include a psychological component.

Pharmacological treatment has for many years included the use of disulfiram (Antabuse), which affects the metabolism of alcohol in the liver. A person who drinks alcohol while taking disulfiram will experience severe discomfort and illness or, in extreme cases, even death. The expectation of illness deters the ingestion of alcohol. Often, however, alcohol abusers do not take the medication, or take it but continue to drink despite the consequences. Moreover, disulfiram treats only the effects, but not the causes, of the disease. This reduces its effectiveness unless used in conjunction with other behavioral therapies.

Figure 13

Disulfiram is a drug approved by the Food and Drug Administration to treat alcoholism.

More recently, the drug naltrexone has been approved as a pharmacological agent to help a person maintain sobriety.⁵⁸ Endorphins are among the hormones believed to be involved in alcohol craving. Naltrexone blocks the receptors for endorphins, thus helping reduce the desire for alcohol. Although clinical trials of naltrexone have been promising, the drug must be taken consistently to be effective. This drug should be used in conjunction with psychosocial therapies. Research is now under way to identify other medications that can be used alone, or in combination with other medications, to treat alcoholism.

Individual-initiated (or "self-help") therapies have traditionally been the backbone of alcohol recovery. The first such program, Alcoholics Anonymous (AA), describes itself as a "worldwide fellowship of men and women who help each other to stay sober." There are formal treatment programs, which include standard behavioral psychology interventions, relapse prevention, and family intervention, all of which can help some patients.

Alcohol and Youth

Alcohol abuse and alcoholism affect not just individuals, but whole families. Children become aware of alcohol at an early age. By about five or six years of age, most children can identify alcoholic beverages by smell alone.⁴⁸ Interviews with eight- and nine-year-old children living in New Zealand revealed that one-third of them were aware of alcohol-related problems in their own environments.¹¹ Most acquired their knowledge about alcohol from siblings. However, one-third cited television as their information source.

By about five or six years of age, most children can identify alcoholic beverages by smell alone.

The prevalence of alcoholism in the United States is such that 76 million Americans, or about 43 percent of the adult population, have been exposed to alcoholism in their families.³⁶ There are thought to be more than 28 million children of alcoholic parents in the United States, with over 11 million of them under the age of 18.³⁷ Children who live in a home with an alcoholic parent are four times more likely than children of nonalcoholic parents to develop alcoholism themselves.³⁶ Children of alcoholic parents are harmed in many other ways as well (see Table 5).

Table 5

Effects of Alcoholism on Children.

The interaction of genetic and environmental factors influences the probability that a young person will abuse alcohol. Children of alcoholic parents generally begin drinking at an earlier age than children of nonalcoholic parents.¹² Children who are restless and easily distracted at age 3 are twice as likely as their more focused counterparts to be diagnosed as alcoholic by age 21.¹⁰

The interaction of genetic and environmental factors influences the probability that a young person will abuse alcohol.

Parental drinking patterns and access to alcohol are associated with adolescents starting and continuing drinking.²⁶ Conversely, children who are warned about the negative consequences of drinking are less likely to begin.² Also, factors such as lack of parental support, monitoring, and communication contribute to alcohol abuse by adolescents. Children who are rejected or mistreated are much more likely to develop problems with alcohol.

Many adolescents develop positive expectations about alcohol use, which factor into their decision about whether to begin drinking. These attitudes are influenced by positive depictions of alcohol use in movies, on television, and in advertisements. Our society has an ambivalent attitude toward alcohol consumption, sometimes restricting it and at other times promoting it. For example, television networks in the United States show advertisements for beer and wine but not for distilled liquor. This voluntary ban on television advertising of hard liquor could end. The positive messages about drinking do not escape the notice of our youngest citizens. A recent study examining 50 children's animated films for examples of tobacco and alcohol use found that 25 of the films (50 percent) depicted alcohol use. Furthermore, the characters drinking alcohol were as likely to be "good" characters as "bad" ones.²²

As children grow older, their drinking or abstinence is influenced more by their peers and less by their parents. College students have been found to pattern their drinking after the amounts they perceive their peers to drink, not what their peers actually consume.^{4, 5, 49} These students consistently overestimated the amount of alcohol consumed by their peers. This bias promotes heavier drinking habits. These studies also show that college students are less prone to heavy drinking after the spring term than the fall term. Presumably, they have experienced some of the negative consequences of alcohol abuse and temper their enthusiasm for drinking. Young people are also prone to model their drinking patterns after people they admire, such as athletes, actors, and musicians.²⁹

Ultimately, each individual must decide whether to use alcohol or not. Students who understand the changes alcohol causes in their bodies and how these changes affect their health and behavior can make informed decisions about drinking. Providing that understanding is the first of the four objectives mentioned in the introduction to this curriculum supplement (see page 1).

Consequences of Alcohol Abuse and Alcoholism

The costs to society

Approximately two-thirds of American adults drink alcohol at least once during the course of a year. Most people drink responsibly, but approximately 13.8 million Americans have problems related to either alcohol abuse or alcoholism.²³ The risk for developing alcohol-related problems is higher among those who begin drinking when they are young. Research shows that biological (genetic) and psychosocial factors combine with environmental factors, such as the availability of alcohol, to increase the risk for developing drinking problems.⁵⁵

Biological (genetic) and psychosocial factors combine with environmental factors, such as the availability of alcohol, to increase the risk for developing drinking problems.

Alcohol abuse and alcoholism have a large economic impact on our society. In 1998, alcohol abuse and alcoholism cost an estimated $185 billion in lost productivity, illness, premature death, and healthcare expenditures. For 1995, these costs were estimated to be over $166 billion, and in 1992, they were $148 billion.⁴⁷ A large portion of these costs is borne, in various ways, by nonabusers (see Figure 14).⁵⁶ While 45 percent of the costs of alcohol abuse fall on the abusers themselves and their families, 38 percent falls on government (in the form of lost or reduced tax revenue). Additional costs to nonabusers include, but are not limited to, the economic costs of the criminal justice system and higher insurance premiums, as well as the social costs of alcohol-related crimes and trauma. Some examples of the social costs of alcohol abuse and alcoholism are discussed in greater detail later.

Figure 14

Distribution of the cost of alcohol abuse in the United States in 1998.

Drinking and driving

Although the proportion of crash fatalities attributable to drinking is declining, the problem is still serious, claiming about 15,000 lives annually in the United States. All states have laws stipulating driver BAC limits. Half the states have already established 0.08 as their per se level (meaning no other evidence of intoxication is required), while the other half currently have a limit of 0.10. Alcohol poses a more serious risk for younger drivers. They have less experience with driving and alcohol and consequently exhibit higher crash rates. Recognizing this fact, all states have laws aimed specifically at preventing underage drinking and driving. Important among these are the minimum legal drinking age of 21 and zero-tolerance laws for underage drinking and driving. In addition, some states have enacted graduated driver licensing (GDL) systems. These systems often feature a three-phase process where 16- and 17-year-old drivers first are required to be supervised at all times by an older driver. The second stage allows them to drive unsupervised during daytime hours. The third stage imposes few restrictions. Recent reports indicate that GDL programs are successful. Crashes involving 16-year-old drivers declined 25 percent in Michigan and 27 percent in North Carolina following implementation of GDL programs.^{19, 52}

Some driving skills are more impaired than others for a given BAC. The brain must control eye movement, briefly focusing on objects and tracking them. Low to moderate BACs (0.03–0.05) can interfere with the ability to track objects. Steering depends upon eye-to-hand reactions together with eye movements. Studies show that people have significant trouble steering a car with BACs beginning at 0.02.⁴² Alcohol also interferes with the brain's information-processing ability. Another important aspect of driving is the ability of the driver to divide his or her attention. A driver must keep the car in its proper lane while at the same time paying attention to the local environment. Alcohol causes people to favor one activity over the other. Typically, alcohol-impaired drivers pay more attention to steering their car than they do to their local surroundings.

Some statistics about alcohol and driving compiled by the U.S. Department of Transportation include the following³⁹:

• Alcohol was involved in 39 percent of fatal crashes and in 7 percent of all crashes in 1997.
• About 3 in every 10 Americans will be involved in an alcohol-related crash at some time in their lives.
• In 1997, the age group of drivers with the highest rates for fatal crashes while intoxicated was 21–24 years old (26.3 percent), followed by ages 25–34 (23.8 percent) and 35–44 (22.1 percent).
• Relatively few problem drinkers (about 7 percent of all drivers) account for over 66 percent of all alcohol-related fatal crashes.
• One-third of all pedestrians 16 years of age or older killed in traffic crashes in 1997 were intoxicated.
• In 1997, an estimated 846 lives were saved by minimum-drinking-age laws.

Figure 15

The Breathalyzer is used by law enforcement personnel to measure BACs.

Drinking and pregnancy

Pregnant women who drink expose their unborn children to alcohol through the placenta. That exposure can lead to fetal alcohol syndrome (FAS), which is characterized by a variety of developmental problems, some of which can be severe (see Table 6, below, and The immune system, on pages 36–37). FAS is estimated to be the most common preventable cause of mental retardation in children. Although not completely understood, the severity of the signs and symptoms seems to be related to the amount, frequency, and timing of alcohol consumption by the mother during pregnancy.

Table 6

Characteristics of Fetal Alcohol Syndrome.

Diagnosis of FAS has been greatly improved by discoveries in alcohol research. Still, because there is no simple laboratory test to detect FAS, it is difficult to estimate its incidence with great accuracy. Complicating this situation are studies that indicate that some physicians are reluctant to make the diagnosis even when it does exist. Presumably, they don't want the child burdened with the stigma associated with FAS, and they recognize that the disorder has limited treatment options. Nevertheless, early and accurate diagnosis and referrals of these children and their parents/care-givers for appropriate medical, social, and educational services is effective.

On the basis of a study in Washington State, it has been estimated that the minimum rate of FAS in the general population is 3.1 per 1,000 live births, or 0.31 percent.¹⁵ Among heavy drinkers, the rate is 4.3 percent, which translates to more than 2,000 cases per year in the United States.⁵⁴ The incidence of FAS varies among different racial and ethnic groups. For example, data from the Centers for Disease Control and Prevention indicate that the incidence of FAS is seven times greater among African Americans than European Americans. Some Native American groups have a 30-fold greater incidence of FAS than the general population.¹³ Since some populations are disproportionately affected by FAS, it is important that researchers, healthcare providers, and educators from these populations be involved in obtaining knowledge about and treatments for this serious disorder.

An additional unestimated number of children are born each year who were exposed to alcohol in utero but do not have the full syndrome. Their condition is termed fetal alcohol effects (FAE). They show one or more birth abnormalities associated with alcohol exposure. These may be either physical or neurodevelopmental.

The deficits associated with FAS are lifelong. Although the distinctive facial features of FAS become less apparent after puberty, the intellectual impairments remain, and emotional, behavioral, and social problems often get worse. In one study, adolescents and adults with FAS were found to have arithmetic skills at the second- to fourth-grade levels.⁵⁴ Children with FAS are often described as hyperactive with short attention spans. They display a number of behavioral problems including poor judgment, failure to consider the consequences of their actions, and failure to appropriately respond to social cues.

Figure 16

Pregnant women should not drink alcohol.

The timing of alcohol exposure during pregnancy is critical to the development of FAS and FAE. By using animal studies to explore the relationship between alcohol exposure and FAS, researchers are able to control not only the timing and dose of alcohol during pregnancy, but also the genetic background and environment of the test animals. A high BAC can destroy nerve cells in the developing rat brain.²⁷ The timing of this nerve-destroying alcohol exposure in rats corresponds to the brain growth spurt in humans, called synaptogenesis, when brain cells form most of their interconnections. In humans, synaptogenesis lasts from about the sixth month of pregnancy to a child's second birthday. In rats, this period occurs for a short period after the pup is born. The scientists exposed newborn rat pups to a BAC of 0.20 (about twice the BAC defined as legally intoxicated in humans). This high BAC was maintained for four hours or longer. A one-time exposure of four hours was sufficient to cause brain cells to die off at a rate nearly 30 times greater than normal.²⁷ Although it is difficult to translate these results from rats to humans, the uncertainties involved led the authors to advise expectant mothers to avoid alcohol entirely during their pregnancies.

A high BAC can destroy nerve cells in the developing rat brain.

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Glossary

absorption phase

The time immediately after consumption when blood alcohol concentration rises sharply.

acetaldehyde

One of the first products of the body's metabolism of alcohol. Acetaldehyde is then converted to carbon dioxide and water, which are excreted from the body.

acute

Short-term.

addiction

A state that involves a physical or psychological dependency on a drug or alcohol.

alcohol

The intoxicating chemical in drinks such as beer, wine, and distilled liquors. Alcohol is a colorless, volatile liquid with the chemical formula C₂H₅OH, also called ethanol or ethyl alcohol. It is a central nervous system depressant.

alcohol abuse

The continued use of alcohol despite the development of social, legal, or health problems.

alcohol addiction, alcohol dependence, or alcoholism

A chronic disease characterized by a strong craving for alcohol, a constant or periodic reliance on use of alcohol despite adverse consequences, the inability to limit drinking, physical illness when drinking is stopped, and the need for increasing amounts of alcohol to feel its effects.

alcohol dehydrogenase (ADH)

An enzyme found in the liver and stomach that helps break down alcohol into substances that can be excreted from the body. Specifically, ADH converts alcohol into acetaldehyde, which is then converted to carbon dioxide and water.

alcoholic hepatitis

Liver disease caused by chronic ingestion of alcohol.

alleles

Different variations of the same gene.

arteries

Thick-walled blood vessels that carry blood away from the heart.

axon

Extensions of nerve cells that carry the nerve impulses away from the nerve cell body.

binge drinking

A pattern of heavy drinking that occurs during an extended period of time set aside for drinking. Has been described as 5/4 binge drinking: five or more drinks in a row on a single occasion for a man or four or more drinks for a woman.

blood alcohol concentration (BAC)

The amount of alcohol in the blood expressed as a percent: grams of ethanol per 100 milliliters (deciliter) of blood.

brainstem

The part of the brain that connects the spinal cord with other parts of the brain.

CAGE

Refers to a questionnaire developed by Dr. John Ewing to screen for alcohol abuse and alcoholism. The name comes from the first letters of key words in the questionnaire: Cut down on drinking, Annoyed by people criticizing your drinking, Guilty about drinking, and drinking as an Eye opener.

cardiovascular system

The organ system that includes the blood, the heart, and blood vessels.

cerebellum

The region of the brain involved with coordination of muscles and maintaining balance and posture.

chromosomes

Rod-like, gene-bearing structures found in the cell nucleus. They are composed of DNA and protein. Humans have 46 chromosomes.

chronic

Long-term; refers to diseases or habits that last a long time, recur, or are difficult to cure.

cirrhosis

Hardening of connective tissue in the liver; fibrosis.

cognitive

Relating mental awareness and judgment.

coronary artery disease

A condition in which cholesterol and fat in the blood build up in clumps known as plaque on the inside walls of arteries. This build-up can restrict the flow of blood and thus of oxygen to the heart. Oxygen starvation of the heart muscle can lead to a heart attack.

cytokines

A class of molecules that help regulate the activities of the immune system.

delirium tremens (DTs)

A serious alcohol-withdrawal syndrome observed in persons who stop drinking alcohol following continuous and heavy consumption. It involves profound confusion, hallucinations, and severe nervous system overactivity, typically beginning between 48 and 96 hours after the last drink.

dendrite

A cluster of small fibers that receive chemical messages from neighboring neurons and transmit them to the cell body.

depressant

A substance that causes sedation and drowsiness. Alcohol is a central nervous system depressant.

diffusion

The passive movement of a substance from a region where it is more concentrated to a region where it is less concentrated. For example, blood alcohol concentration decreases as alcohol diffuses from the blood into body tissues.

distillation

A process that uses heat to purify or separate a fraction of a complex substance. Various components of the mixture are collected as gases condense to liquids. Liquors are produced through distillation.

distribution phase

The process by which ethanol spreads from the blood to all tissues and fluids in proportion to their relative water content.

dopamine

A chemical messenger (neurotransmitter) that regulates brain processes such as those that control movements, emotions, pleasure, and pain.

drug

In a medical context, any substance used in the diagnosis, prevention, treatment, or cure of a disease. In an abuse context, any substance that alters consciousness and may be habit forming.

elimination phase

The combined processes of metabolism and excretion that decrease blood alcohol concentration.

endorphins

A class of protein hormones produced in the brain that have pain-relieving properties.

endotoxin

A bacterial toxin composed of protein, lipid, and polysaccharides.

enzyme

A class of proteins that speed up chemical reactions in the body.

esophageal cancer

Cancer of the esophagus (throat).

esophagus

The part of the digestive system that receives food. This is the tube leading from the mouth to the stomach.

ethanol

See alcohol.

ethyl alcohol

See alcohol.

euphoria

A feeling of well being.

excretion

The loss of ethanol from the body through urine, sweat, breath, and other routes of exit.

fermentation

An anaerobic process (not requiring oxygen) in which organisms convert sugars into alcohol and carbon dioxide. This process does not occur in animals but is used extensively by yeast (single-celled fungi). Humans exploit this phenomenon to make bread (the gas bubbles expand the dough) as well as wine and beer (for the alcohol produced).

fetal alcohol effects (FAE)

A pattern of mental and physical birth abnormalities associated with children whose mothers abused alcohol during pregnancy. The symptoms are less severe than those in fetal alcohol syndrome.

fetal alcohol syndrome (FAS)

A pattern of mental and physical birth abnormalities found in some children of mothers who drank excessively during pregnancy.

fibrosis

A condition within a tissue or an organ that is characterized by an increase in fibrous tissue.

free radicals

Short-lived, highly reactive molecules that have one or more unpaired electrons.

functional tolerance

A state in which a chronic alcohol abuser learns to function under the influence of alcohol. The impairment normally associated with performing a familiar task is reduced, but the ability to perform unfamiliar tasks remains impaired.

gastritis

An inflammation of the stomach lining.

gene

The functional and physical unit of heredity. Genes are segments of DNA found along a chromosome. They typically encode information used to produce a specific protein.

genetically predisposed

Having variations in genes that increase the probability of displaying a given trait.

genotype

The genetic makeup of an individual. The expression of genotype as visible traits is called the phenotype.

glucagon

A pancreatic hormone that increases the concentration of blood sugar. Its effect is opposite to that of insulin.

growth hormones

Hormones that affect growth of the body, for example, by stimulating cell division and bone growth.

hallucination

The experience of sights and sounds that are not actually present.

hippocampus

A part of the brain that is responsible for learning and spatial relations.

hormone

A chemical released into the bloodstream that stimulates or inhibits an action in another body tissue.

hypertension

A condition of abnormally high blood pressure.

hypothalamus

A small area of the brain that is responsible for regulating the release of some hormones and maintaining body temperature.

impairment

Diminished ability, such as when alcohol decreases motor function or interferes with thinking.

inflammation

The body's response to tissue damage characterized by redness, swelling, heat, and pain.

inhibition

As related to behavior, restraint on instinctive impulses.

insulin

A hormone produced in the pancreas that lowers the blood sugar level. Its effect is opposite to that of glucagon.

intoxication

The condition of being drunk. An abnormal state that is essentially alcohol poisoning. It is characterized by slurred speech and a loss of coordination.

limbic system

The areas of the brain involved with emotions and memory.

lymphocytes

The white blood cells, the T cells, and B cells of the immune system.

metabolism

All the chemical reactions that enable the body to function. Nutrients and materials are broken down into stored energy or into usable compounds. The biological transformation of ethanol to acetaldehyde and other products.

mitochondria

The cellular organelles that function as energy factories in the cell. Mitochondria produce ATP (the energy currency of our bodies).

motor function

The ability to use and control muscles and movements. Alcohol and drugs interfere with the neuronal messages from our brain to muscles resulting in impaired motor function.

naltrexone

A drug that has been effective in the recovery from alcoholism. It blocks receptors for endorphins, thereby reducing alcohol cravings. Use of the drug in combination with psychosocial therapy improves the effectiveness of treatment.

neurons

One of two principal classes of cells in the nervous system, composed of three parts: the cell body, dendrites, and axons. Neurons receive and conduct electrical impulses.

neurotransmission

The process by which neurons transmit messages to other neurons, muscle cells, or gland cells.

neurotransmitter

A chemical substance that transmits a nerve impulse across a synapse.

nucleus accumbens

The part of the brain related to the limbic system that controls emotions.

pancreatitis

An acute or chronic inflammation of the pancreas associated with alcoholism and marked by severe abdominal pain, nausea, and fever.

pharmacokinetics

The study of the absorption, distribution, and elimination of alcohol and other drugs.

physical dependence

A condition in which the presence of a drug or alcohol is required to maintain normal functioning of the central nervous system. (See withdrawal symptoms.) Physical dependence is caused by changes in the relationships among nerve cell membranes, neurotransmitters and their receptors, and the reward pathway.

placenta

A membranous organ that develops during pregnancy. It lines the uterine wall, partially envelopes the fetus, and is attached to the umbilical cord. The placenta exchanges nutrients, wastes, and gases between maternal and fetal blood. Substances ingested by the mother during pregnancy pass through the placenta to the fetus.

polygenic

A trait, such as alcoholism, whose expression is influenced by more than one gene.

predispose

To make susceptible, such as to certain health problems or to alcohol dependency. For example, the presence of certain gene combinations or environmental conditions can predispose an individual to develop alcoholism.

prefrontal cortex

The part of the frontal lobe of the brain that relates to pleasure.

psychosocial

Involving both social and psychological behavior.

reinforcement

The positive effects of alcohol, such as its euphoric and anxiety-reducing effects, that help promote continued drinking. Specific neurotransmitters and regions of the brain are implicated in alcohol's reinforcing effects.

relapse

To fall back or revert to an earlier state; to regress after partial recovery. In the context of alcohol abuse and alcoholism, relapse means to start drinking again after giving up alcohol.

reproductive hormones

Hormones that influence development of secondary sexual traits and the production of or maturation of the sperm and the egg. These include testosterone, leutinizing hormone (LH), follicle stimulating hormone (FSH), estrogen, and progesterone.

reward pathway

A specialized network of neurons in the brain that produce and regulate pleasure associated with eating, drinking, and sex. These neurons use dopamine as a neurotransmitter. Alcohol activates the reward pathway. Alcohol abusers and alcoholics use alcohol to avoid the pain (lack of pleasure) associated with withdrawal.

sobriety

The condition of refraining from drinking alcohol.

sodium-potassium pump

Proteins embedded in the cell membrane that actively move potassium ions into the cell and, at the same time, move sodium ions out.

soluble

Capable of being dissolved in a solvent such as water or another liquid.

stimulant

A substance such as caffeine, nicotine, or amphetamines that temporarily arouses or accelerates physiological activity in the brain.

stupor

A state of impaired consciousness accompanied by diminished responsiveness to external stimuli and surroundings.

synapse

The tiny space between two nerve cells or between a nerve cell and a muscle or gland cell.

synaptogenesis

The time frame from about the sixth month of pregnancy to a child's second birthday when the brain experiences a growth spurt and brain cells form most of their interconnections.

testosterone

A sex hormone responsible for secondary sex characteristics. Present in both males and females but at lower concentrations in females.

tolerance

The body's ability to adapt to chronic alcohol or substance use. Higher BACs are needed to produce intoxication in alcohol abusers and alcoholics. Chronic alcohol use leads to increased levels of liver enzymes that metabolize alcohol. Since they allow the liver to more efficiently break down alcohol, the individual must consume a larger dose to reach a given BAC. This increased level of alcohol can severely damage the body's physiological systems, despite the apparent "normalcy" displayed by the individual.

tuberculosis

A communicable disease caused by a bacterium that causes lesions of the lung, bone, and other body parts. Drug and alcohol abusers are infected at a rate 15–200 times greater than that of nonabusers.

ventral tegmental area

Component of the reward pathway in the brain; located near the top of the brainstem.

withdrawal symptoms

Severe alcohol cravings as well as physical and psychological problems caused by the withdrawal from excessive, chronic alcohol consumption. The biochemical changes lead to short-term memory loss, disruption of cognitive and motor function, reduced perceptual abilities, and emotional and personality changes that include acts of aggression.

zero-tolerance laws

Laws that exist in all states and the District of Columbia making it illegal for anyone under the age of 21 to drive a car after drinking any alcohol.