What Causes Alcoholism?

What Causes Alcoholism?

People have been drinking alcohol for perhaps 15,000 years. Just drinking steadily and consistently over time can cause a sense of dependence and withdrawal symptoms during periods of abstinence; this physical dependence, however, is not the sole cause of alcoholism. To develop alcoholism, other factors usually come into play, including biology and genetics, culture, and psychology.

Brain Chemistry and Genetic Factors.

The craving for alcohol during abstinence, the pain of withdrawal, and the high rate of relapse are due to the brain's adaptation to and dependence on the changes in its own chemistry caused by long term use of alcohol. Alcohol causes relaxation and euphoria but also acts as a depressant on the central nervous system. Even after years of research, experts still do not know exactly how alcohol affects the brain or how the brain affects alcoholism. Alcohol appears to have major effects upon the hippocampus, an area in the brain associated with learning and memory and the regulation of emotion, sensory processing, appetite, and stress. Alcohol breaks down into products called fatty acid ethyl esters, which appear to inhibit important neurotransmitters (chemical messengers in the brain) in the hippocampus. Of particular importance to researchers of alcoholism are the neurotransmitters gamma aminobutyric acid (GABA), dopamine, and serotonin, which are strongly associated with, emotional behavior and cravings. Research indicates that dopamine transmission, particularly, is strongly associated with the rewarding properties of alcohol, nicotine, opiates, and cocaine. Investigators have focused on nerve-cell structures known as dopamine D2 receptors (DRD2), which influence the activity of dopamine. Mice with few of these receptors show low interest in and even aversion to alcohol. In people with severe alcoholism, researchers have located a gene that alters the function of DRD2. This gene is also found in people with attention deficit disorder, who have an increased risk for alcoholism, and in people with Tourette's syndrome and autism. One major study, however, found no connection at all between the DRD2 gene and alcoholism. More work in this area is needed. Researchers are also investigating genes that regulate certain enzymes known as kinases that affect alcohol uptake in the brain as well as genes that affect serotonin. Even if genetic factors can be identified, however, they are unlikely to explain all cases of alcoholism. In fact, lack of genetic protection may play a role in alcoholism. Because alcohol is not found easily in nature, genetic mechanisms to protect against excessive consumption may not have evolved in humans as they frequently have for protection against natural threats.

Who Becomes an Alcoholic?

General Risks and Age.

Some population studies indicate that in a single year, between 7.4% and 9.7% of the population are dependent on alcohol, and between 13.7% and 23.5% of Americans are alcohol-dependent at some point in their lives. A 1996 national survey reported that 11 million Americans are heavy drinkers (five or more drinks per occasion on five or more days in a month) and 32 million engaged in binge drinking (five or more drinks on one occasion) in the month previous to the survey. People with a family history of alcoholism are more likely to begin drinking before the age of 20 and to become alcoholic. But anyone who begins drinking in adolescence is at higher risk. Currently 1.9 million young people between the ages of 12 and 20 are considered heavy drinkers and 4.4 million are binge drinkers. Although alcoholism usually develops in early adulthood, the elderly are not exempt. In fact, in one study, 15% of men and 12% of women over age 60 drank more than the national standard for excess alcohol consumption. Alcohol also affects the older body differently; people who maintain the same drinking patterns as they age can easily develop alcohol dependency without realizing it. Physicians may overlook alcoholism when evaluating elderly patients, mistakenly attributing the signs of alcohol abuse to the normal effects of the aging process.

Gender.

Most alcoholics are men, but the incidence of alcoholism in women has been increasing over the past 30 years. About 9.3% of men and 1.9% of women are heavy drinkers, and 22.8% of men are binge drinkers compared to 8.7% of women. In general, young women problem drinkers follow the drinking patterns of their partners, although they tend to engage in heavier drinking during the premenstrual period. Women tend to become alcoholic later in life than men, and it is estimated that 1.8 million older women suffer from alcohol addiction. Even though heavy drinking in women usually occurs later in life, the medical problems women develop because of the disorder occur at about the same age as men, suggesting that women are more susceptible to the physical toxicity of alcohol.

Family History and Ethnicity.

The risk for alcoholism in sons of alcoholic fathers is 25%. The familial link is weaker for women, but genetic factors contribute to this disease in both genders. In one study, women with alcoholism tended to have parents who drank. Women who came from families with a history of emotional disorders, rejecting parents, or early family disruption had no higher risk for drinking than women without such backgrounds. A stable family and psychological health were not protective in people with a genetic risk. Unfortunately, there is no way to predict which members of alcoholic families are most at risk for alcoholism. Irish and Native Americans are at increased risk for alcoholism; Jewish and Asian Americans are at decreased risk. Overall, there is no difference in alcoholic prevalence between African Americans, whites, and Hispanic people. Although the biological causes of such different risks are not known, certain people in these population groups may be at higher or lower risk because of the way they metabolize alcohol. One study of Native Americans, for instance, found that they are less sensitive to the intoxicating effects of alcohol. This confirms other studies, in which young men with alcoholic fathers exhibited fewer signs of drunkenness and had lower levels of stress hormones than those without a family history. In other words, they "held their liquor" better. Experts suggest such people may inherit a lack of those warning signals that ordinarily make people stop drinking. Many Asians, on the other hand, are less likely to become alcoholic because of a genetic factor that makes them deficient in aldehyde dehydrogenase, a chemical used by the body to metabolize ethyl alcohol. In its absence, toxic substances build up after drinking alcohol and rapidly lead to flushing, dizziness, and nausea. People with this genetic susceptibility, then, are likely to experience adverse reactions to alcohol and therefore not become alcoholic. This deficiency is not completely protective against drinking, however, particularly if there is added social pressure, such as among college fraternity members. It is important to understand that, whether it is inherited or not, people with alcoholism are still legally responsible for their actions.

Emotional Disorders.

Severely depressed or anxious people are at high risk for alcoholism, smoking, and other forms of addiction. Major depression, in fact, accompanies about one-third of all cases of alcoholism. It is more common among alcoholic women (and women in general) than men. Interestingly, one study indicated that depression in alcoholic women may cause them to drink less than nondepressed alcoholic women, while in alcoholic men, depression has the opposite effect. Depression and anxiety may play a major role in the development of alcoholism in the elderly, who are often subject to dramatic life changes, such as retirement, the loss of a spouse or friends, and medical problems. Problem drinking in these cases may be due to self-medication of the anxiety or depression. It should be noted, however, that in all adults with alcoholism these mood disorders may be actually caused by alcoholism and often abate after withdrawal from alcohol.

Personality Traits.

Studies are finding that alcoholism is strongly related to impulsive, excitable, and novelty-seeking behavior, and such patterns are established early on, if not inherited. People with attention deficit hyperactivity disorder, a condition that shares these behaviors, have a higher risk for alcoholism. Children who later become alcoholics or who abuse drugs are more likely to have less fear of new situations than others, even if there is a risk for harm. In a test of mental functioning, alcoholics (mostly women) did not show any deficits in thinking but they were less able to inhibit their responses than nonalcoholics. It was once thought that a family history of passivity and abnormal dependency needs increased the risk for alcoholism, but studies have not borne out this theory.

Socioeconomic Factors.

It has been long thought that alcoholism is more prevalent in people with lower educational levels and in those who were unemployed. A thorough 1996 study, however, reported that the prevalence of alcoholism among adult welfare recipients was 4.3% to 8.2%, which was comparable to the 7.4% found in the general population. There was also no difference in prevalence between poor African Americans and poor whites. People in low-income groups did display some tendencies that differed from the general population. For instance, as many women as men were heavy drinkers. Excessive drinking may be more dangerous in lower income groups; one study found that it was a major factor in the higher death rate of people, particularly men, in lower socioeconomic groups compared with those in higher groups.

Geographic Factors.

Although 54% of urban adults use alcohol at least once a month compared to 42% in nonurban areas, living in the city or the country does not affect the risks for bingeing or heavy alcohol use. One study reported that people in the north central U.S. are at highest risk for heavy drinking (6.4% heavy use and 19% binge drinking) and those in the Northeast have the lowest risk (4.5% heavy use and 13% binge drinking).

Sugar Cravings.

People who crave sugar may also be at higher risk for alcoholism. In one recent study, 62% of male alcoholics enjoyed a sweet sugar solution compared with only 21% of those without a drinking problem. It is not known, however, whether having a "sweet tooth" can be an early predictor of alcoholism or whether alcohol abusers simply develop a taste for sweetness as a result of their chronic alcohol abuse.