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Alcohol Use Disorders
Definition
A variety of terms have been used to describe the spectrum of medical, psychological, behavioral, and social problems associated with excessive consumption of alcohol (alcohol problems) . The Diagnostic and Statistical Manual of Mental Disorders , 5th edition (DSM-5) replaced the terminology of alcohol abuse and alcohol dependence with the term alcohol use disorder ( Table 364-1 ) to describe more clearly the spectrum of symptoms experienced by patients. Patients who meet 2 or 3 of the 11 criteria for alcohol use disorder are considered to have mild, 4 or 5 criteria moderate, and 6 to 11 criteria severe alcohol use disorder. Recent epidemiologic data suggest that no level of alcohol consumption reduces overall health risks and that any level of intake probably increases health risks.
Alcoholism , which is perhaps the most widely used term to describe patients with alcohol problems, is an often progressive and sometimes fatal chronic disease that is related to genetic, psychosocial, and environmental influences and that is characterized by preoccupation with alcohol, an impaired ability to control its intake despite the consequences, and distorted thinking, especially denial. Because the term alcoholism is so broad, however, it also can be imprecise in defining the entire spectrum of alcohol problems and generally should be avoided.
At-risk drinking is a level of alcohol consumption that imparts health risks (see Table 364-1 ). This category of drinking behavior has been identified on the basis of epidemiologic evidence that certain threshold levels of alcohol consumption are associated with increased risk for specific health problems. At-risk drinking is defined differently for men younger than age 65 years than for women of all ages because of generally lower body weights and lower rates of metabolism of alcohol in women. The definition in men older than age 65 years is the same as in women because of the age-related increased risk for alcohol problems, in part owing to changes in alcohol metabolism in older individuals. Binge drinking or heavy drinking is the episodic consumption of large amounts of alcohol, usually five or more drinks per occasion for men and four or more drinks per occasion for women. One standard drink contains 12 g of pure alcohol, an amount equivalent to that contained in 5 ounces of wine, 12 ounces of beer, or 1.5 ounces of 80-proof spirits.
TABLE 364-1
TERMS AND CRITERIA FOR PATTERNS OF ALCOHOL USE
From American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders . 5th ed. Arlington, VA: American Psychiatric Publishing; 2013.
| AT-RISK DRINKING |
| Men: >14 drinks/week or >4 drinks/day Women: >7 drinks/week or >3 drinks/day |
| ALCOHOL USE DISORDER CRITERIA ∗ |
| Tolerance Withdrawal More use than intended Craving Unsuccessful attempts to cut down Excessive time acquiring alcohol Activities given up because of use Use despite negative effects Failure to fulfill major role obligations Recurrent use in hazardous situations Continued use despite social or intrapersonal problems |
∗ Mild = 2-3 criteria, moderate = 4-5 criteria, severe = 6 or more criteria.
Abstainers are individuals who consume no alcohol. Moderate drinking is defined by the U.S. National Institute on Alcohol Abuse and Alcoholism as the average number of drinks consumed daily that places an adult at low risk for alcohol problems.
Epidemiology
In national surveys, 50% of American adults reported that they use alcoholic beverages (liquor, wine, or beer). The 2020 National Survey on Drug Use and Health demonstrated that among the 138.5 million Americans who were current alcohol users, 61.6 million people (or 44.4%) were classified as binge drinkers and 17.7 million people (or 13%) were classified as heavy drinkers. These data emphasize that alcohol use disorders are among the most prevalent medical, behavioral, or psychiatric disorders in the general population.
Among individuals who use alcohol, many experience problems because of their drinking. An estimated nearly $250 billion is spent by American society each year to treat alcohol use disorders and to recover the costs of alcohol-related economic losses. In the United States, nearly 90,000 deaths per year are attributed to alcohol use disorders, and excessive alcohol consumption ranks as the third leading preventable cause of death after cigarette smoking and obesity.
Despite the high number of individuals with alcohol use disorder who by definition need treatment, only a minority (approximately 20%) have ever received treatment. In addition, individuals with alcohol use disorder are more likely to experience other substance use disorders ( Chapter 365 ) as well as psychiatric comorbidity ( Chapter 362 ), especially depression, bipolar disorder, antisocial disorder, and borderline personality disorder. Alcohol use disorder is prevalent throughout all sociodemographic groups. The “skid row” stereotype of the alcohol-dependent patient is much more the exception than the rule.
The prevalence of alcohol use disorders is higher in most health care settings than it is in the general population because alcohol problems often result in treatment-seeking behaviors. The prevalence of problem drinking in general outpatient and inpatient medical settings has been estimated between 15 and 40%. These data strongly support the need for physicians to screen all patients for AUD.
Pathobiology
Beverage alcohol contains ethanol, which acts as a sedative-hypnotic drug. Alcohol is absorbed rapidly into the blood stream from the gastrointestinal tract. Because women have lower levels of gastric alcohol dehydrogenase, which is the enzyme primarily responsible for metabolizing alcohol, they experience higher blood alcohol concentrations than do men who consume similar amounts of ethanol per kilogram of body weight. The absorption of alcohol can be affected by other factors, including the presence of food in the stomach and the rate of alcohol consumption. By means of metabolism in the liver, alcohol is converted to acetaldehyde and acetate ( Fig. 364-1 ). Metabolism is proportional to an individual’s body weight, but a variety of other factors can affect how alcohol is metabolized. A genetic variation in a significant proportion of the East Asian population alters the structure of an aldehyde dehydrogenase isoenzyme, thereby resulting in the development of an alcohol flush reaction, which includes facial flushing, hot sensations, tachycardia, and hypotension.
Neurologic Effects
In the brain, alcohol affects a variety of receptors, including γ-aminobutyric acid (GABA), N -methyl- d -aspartate, and opioid receptors. Glycinuric and serotoninergic receptors also are thought to be involved in the interaction between alcohol and the brain. The phenomena of reinforcement and cellular adaptation are thought, at least in part, to influence alcohol-dependent behaviors. Alcohol is known to be reinforcing because withdrawal from ethanol and ingestion of ethanol itself are known to promote further alcohol consumption. After chronic exposure to alcohol, some brain neurons seem to adapt to this exposure by adjusting their response to normal stimuli. This adaptation is thought to be responsible for the phenomenon of tolerance, whereby increasing amounts of alcohol are needed over time to achieve the same desired effects. Although much has been learned about the variety of effects alcohol can have on various brain receptors, no single receptor site has been identified. A number of neuropsychological disorders are seen in association with chronic ethanol use, including impaired short-term memory, cognitive dysfunction, and perceptual difficulties.
Because ethanol is a central nervous system depressant, the body’s natural response to withdrawal of the substance is a hyperexcitable neurologic state. This state is thought to be the result of adaptive neurologic mechanisms being unrestrained by alcohol, with an ensuing release of a variety of neurohumoral substances, including norepinephrine. In addition, chronic exposure to alcohol results in a decrease in the number of GABA receptors and impairs their function.
In addition to the acute neurologic manifestations of intoxication and withdrawal, alcohol has major chronic neurologic effects. About 10 million Americans have identifiable nervous system impairment from chronic alcohol use. Individual predisposition to these disorders is highly variable and is related to genetics, environment, sociodemographic features, and gender; the relative contribution of these factors is unclear.
Liver and Pancreas
Direct liver toxicity may be among the most important consequences of acute and chronic alcohol use ( Chapter 138 ). A variety of histologic abnormalities ranging from inflammation to scarring and cirrhosis have been described. The pathophysiologic mechanism of these effects is thought to include the direct release of toxins and the formation of free radicals, which can interact negatively with liver proteins, lipids, and DNA. The risk for pancreatitis in individuals with alcohol dependence is approximately four times that in the general population. Quantity and duration of alcohol exposure and a history of pancreatitis are predictive of future episodes.
Other Organ Systems
Alcohol also has substantial negative effects on the heart and cardiovascular system. Direct toxicity to myocardial cells can result in heart failure ( Chapter 45 ), and chronic heavy alcohol consumption is considered to be a major contributor to atrial fibrillation and hypertension ( Chapters 52 and 64 ). Other organ systems that experience significant direct toxicity from alcohol include the gastrointestinal tract (esophagus, stomach), immune system (bone marrow, immune cell function), and endocrine system (pancreas, gonads).
Carcinogenesis
The amount of alcohol exposure that increases the risk of cancer may vary widely and may not correlate with what might be considered to be “safe” levels of alcohol consumption. For squamous cell carcinomas of the esophagus ( Chapter 178 ) and of the head and neck ( Chapter 176 ), the co-occurrence of alcohol and tobacco abuse seems to be synergistic. Either heavy alcohol use or smoking individually increases the rate of oropharyngeal cancer by about six or seven times that of the general population, whereas the rate for people with both risk factors is about 40 times that of the general population. Patients with alcohol-induced liver disease who also have a history of hepatitis B or C are at particularly increased risk for hepatocellular carcinoma ( Chapter 181 ).
Clinical Manifestations
Alcohol has a variety of specific acute and chronic effects. The acute effects seen most commonly are alcohol intoxication and alcohol withdrawal. Chronic clinical effects of alcohol include almost every organ system.
Acute Effects
Alcohol Intoxication
After entering the blood stream, alcohol rapidly passes through the blood-brain barrier. The clinical manifestations of alcohol intoxication are related directly to the blood level of alcohol. Because of tolerance, individuals chronically exposed to alcohol generally experience less severe effects at a given blood alcohol level than do individuals who are not chronically exposed to alcohol.
The symptoms of mild alcohol intoxication in nontolerant individuals typically occur at blood alcohol levels of 20 to 100 mg/dL and include euphoria, mild muscle incoordination, and mild cognitive impairment. In the United States, a blood alcohol level of 80 mg/dL is considered legally intoxicated, although states often enforce driving while intoxicated laws at lower levels for drivers under age 21 years. At higher blood alcohol levels (100 to 200 mg/dL), more substantial neurologic dysfunction occurs, including more severe mental impairment, ataxia, and prolonged reaction time. Individuals with blood alcohol levels in these ranges can be obviously intoxicated, with slurred speech and lack of coordination. These effects progress as the blood alcohol level rises to higher levels, to the point at which stupor, coma, and death can occur at levels equal to or greater than 300 to 400 mg/dL, especially in individuals who are not tolerant to the effects of alcohol. The usual cause of death in individuals with very high blood levels of alcohol is respiratory depression and hypotension.
Alcohol Withdrawal Syndrome
Alcohol withdrawal can occur when individuals decrease their alcohol use or stop using alcohol altogether. The severity of symptoms can vary greatly. Many individuals experience alcohol withdrawal without seeking medical attention, whereas others require hospitalization for severe illness.
The clinical manifestations of alcohol withdrawal include adrenergic hyperactivity with tachycardia and diaphoresis. Patients also experience tremulousness, anxiety, and insomnia. More severe alcohol withdrawal can result in nausea and vomiting, which can exacerbate metabolic disturbances. Perceptual abnormalities, including visual and auditory hallucinations and psychomotor agitation, are common manifestations of more moderate to severe alcohol withdrawal. Generalized seizures ( Chapter 372 ) may occur during alcohol withdrawal.
The time course of the alcohol withdrawal syndrome can vary within an individual and by symptom complex, and the overall duration of symptoms can be a few to several days ( Fig. 364-2 ). Tremor, which is typically among the earliest symptoms, can occur within 8 hours of the last drink. Symptoms of tremulousness and motor hyperactivity usually peak within 24 to 48 hours. Although mild tremor typically involves the hands, more severe tremors can involve the entire body and greatly impair a variety of basic motor functions. Perceptual abnormalities typically begin within 24 to 36 hours after the last drink and resolve within a few days. When withdrawal seizures occur, they are typically generalized tonic-clonic seizures and most often occur within 12 to 24 hours after reduction of alcohol intake. Seizures can occur, however, at later time periods as well.
The most severe manifestation of the alcohol withdrawal syndrome is delirium tremens. This symptom complex includes disorientation, confusion, hallucination, diaphoresis, fever, and tachycardia. Delirium tremens typically begins after 2 to 4 days of last alcohol intake, and its most severe form can result in death.
The alcohol withdrawal syndrome can exacerbate existing medical conditions such as hypertension and seizure disorders. In addition, it can complicate and adversely affect inpatient admissions for conditions such as trauma, which is often associated with alcohol use disorder.
Chronic Effects
Unlike acute manifestations, including intoxication and withdrawal, which are generally stereotypical in their appearance and time course, the chronic manifestations of alcohol use disorder tend to be more varied. Many patients with alcohol dependence may have no evidence of any chronic medical manifestations for many years. Over time, however, all major organ systems can be affected, especially the nervous system, cardiovascular system, liver, gastrointestinal system, pancreas, hematopoietic system, and endocrine system ( Table 364-2 ). Patients who drink are at risk for a variety of malignant neoplasms, such as head and neck ( Chapter 176 ), esophageal ( Chapter 178 ), colorectal ( Chapter 179 ), breast ( Chapter 183 ), and liver ( Chapter 181 ) cancers. Excessive alcohol use often causes significant psychiatric and social morbidity that can be more common and more severe than the direct medical effects, especially earlier in the course of problem drinking.
TABLE 364-2
ALCOHOL-RELATED COMPLICATIONS
| SYSTEM/REALM OF PROBLEM | COMPLICATIONS |
|---|---|
| Nervous system | Intoxication Withdrawal Cognitive impairment Cerebellar degeneration Peripheral neuropathy |
| Cardiovascular system | Cardiac arrhythmias Chronic cardiomyopathy Hypertension |
| Liver | Fatty liver Alcoholic hepatitis Cirrhosis |
| Gastrointestinal tract, esophagus | Chronic inflammation Malignant neoplasms Mallory-Weiss tears Esophageal varices |
| Stomach | Gastritis Peptic ulcer disease |
| Pancreas | Acute pancreatitis Chronic pancreatitis |
| Other medical problems | Cancers: mouth, oropharynx, esophagus, colorectal, breast, hepatocellular carcinoma Pneumonia Tuberculosis |
| Psychiatric | Depression Anxiety Suicide |
| Behavioral and psychosocial | Injuries Violence Crime Child or partner abuse Tobacco, other drug abuse Unemployment Legal problems |
Nervous System
In the central nervous system, the major effect is cognitive impairment. Patients may present with mild to moderate short-term or long-term memory problems or may have severe dementia resembling Alzheimer disease ( Chapter 371 ). The degree to which the direct toxic effect of alcohol is responsible for these problems or the impact of alcohol-related nutritional deficiencies is uncertain ( Chapter 384 ). The deficiency of vitamins such as thiamine may play a major role in promoting alcoholic dementia and severe cognitive dysfunction, as is seen in Wernicke encephalopathy and Korsakoff syndrome ( Chapter 384 ). Alcohol also causes a polyneuropathy that can present with paresthesias, numbness, weakness, and chronic pain ( Chapters 384 and 388 ). As with the central nervous system, peripheral nervous system effects are thought to be caused by a combination of the direct toxicity of alcohol and nutritional deficiencies. A small proportion (<1%) of patients with alcohol dependence may develop midline cerebellar degeneration, which presents as an unsteady gait.
Cardiovascular System
The most common cardiovascular complications of chronic alcohol consumption are cardiomyopathy ( Chapters 45 and 47 ), hypertension ( Chapter 64 ), and supraventricular arrhythmias ( Chapter 52 ). Data demonstrate that excessive alcohol use increases the risk of chronic heart failure, myocardial infarction, and atrial fibrillation to a similar degree as other established “traditional” risk factors, and it also increases the risk for acute cardiac decompensation.
Alcoholic cardiomyopathy, which presents clinically in a manner similar to other causes of heart failure with a reduced ejection fraction ( Chapter 45 ), is the most common cause of nonischemic cardiomyopathy in Western countries, accounting for about 45% of cases. As with other causes, alcoholic cardiomyopathy also responds to conventional treatments of heart failure ( Chapter 46 ). Increasing levels of alcohol consumption also are associated with increasing levels of systolic and diastolic hypertension ( Chapter 64 ). Alcoholic cardiomyopathy also is associated with arrhythmias, in particular, ventricular arrhythmias ( Chapter 53 ).
The most common arrhythmias associated with chronic alcohol use include atrial fibrillation and supraventricular tachycardia, especially in the setting of acute intoxication and withdrawal but also with even moderate intake ( Chapter 52 ). Heavy alcohol consumption is also a risk factor for a prolonged QTc interval.
Liver
Alcohol use is the major cause of morbidity and mortality from liver disease in the United States, where an estimated 2 million or more people with known alcoholic liver disease ( Chapter 138 ) have hepatic cirrhosis ( Chapter 139 ). Factors that predispose to early liver disease include the quantity and duration of alcohol exposure, female gender, and malnutrition. The range of clinical manifestations includes acute fatty liver and alcoholic hepatitis ( Chapter 138 ), as well as cirrhosis ( Chapter 139 ). Fatty liver associated with alcohol ingestion can be asymptomatic or associated with nonspecific abdominal discomfort. Alcoholic hepatitis can present as an asymptomatic condition identified by abnormalities in liver enzymes or as an acute episode with abdominal pain, nausea, vomiting, and fever.
Alcohol-related cirrhosis is a major cause of death in the United States ( Chapter 140 ). Although patients are often asymptomatic, patients with more advanced cirrhosis may present with a variety of symptoms and signs, including jaundice, ascites, and coagulopathy, that can benefit from management approaches tailored to this patient population. Cirrhosis is also associated with gastrointestinal bleeding from esophageal varices ( Chapter 124 ).
Gastrointestinal Disease
Chronic alcohol use is associated with a variety of esophageal problems, including esophageal varices, Mallory-Weiss tears, and squamous cell carcinoma of the esophagus ( Chapter 178 ). The risk for squamous cell carcinoma is increased further in patients who smoke tobacco and drink alcohol ( Chapter 178 ). Patients with these problems can present with difficulty swallowing, chest pain, gastrointestinal blood loss, and weight loss. Acute alcoholic gastritis typically presents with abdominal discomfort, nausea, and vomiting ( Chapter 118 ).
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