Five distinct subtypes of alcoholism identified

Jun 29 2007

Analyses of a national sample of individuals with alcohol dependence (alcoholism) reveal five distinct subtypes of the disease, according to a new study by scientists at the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of the National Institutes of Health (NIH).

Our findings should help dispel the popular notion of the typical alcoholic, notes first author Howard B. Moss, M.D., NIAAA Associate Director for Clinical and Translational Research.We find that young adults comprise the largest group of alcoholics in this country, and nearly 20 percent of alcoholics are highly functional and well-educated with good incomes. More than half of the alcoholics in the United States have no multigenerational family history of the disease, suggesting that their form of alcoholism was unlikely to have genetic causes.

Clinicians have long recognized diverse manifestations of alcoholism, adds NIAAA Director Ting-Kai Li, M.D,and researchers have tried to understand why some alcoholics improve with specific medications and psychotherapies while others do not. The classification system described in this study will have broad application in both clinical and research settings. A report of the study is now available online in the journal Drug and Alcohol Dependence.

Previous efforts to identify alcoholism subtypes focused primarily on individuals who were hospitalized or otherwise receiving treatment for their alcoholism. However, recent reports from NIAAA's National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a nationally representative epidemiological study of alcohol, drug, and mental disorders in the United States, suggest that only about one-fourth of individuals with alcoholism have ever received treatment. Thus, a substantial proportion of people with alcoholism were not represented in the samples previously used to define subtypes of this disease.

In the current study, Dr. Moss and colleagues applied advanced statistical methods to data from the NESARC. Their analyses focused on the 1,484 NESARC survey respondents who met diagnostic criteria for alcohol dependence, and included individuals in treatment as well as those not seeking treatment. The researchers identified unique subtypes of alcoholism based on respondents family history of alcoholism, age of onset of regular drinking and alcohol problems, symptom patterns of alcohol dependence and abuse, and the presence of additional substance abuse and mental disorders:

Young Adult subtype: 31.5 percent of U.S. alcoholics. Young adult drinkers, with relatively low rates of co-occurring substance abuse and other mental disorders, a low rate of family alcoholism, and who rarely seek any kind of help for their drinking.

Young Antisocial subtype: 21 percent of U.S. alcoholics. Tend to be in their mid-twenties, had early onset of regular drinking, and alcohol problems. More than half come from families with alcoholism, and about half have a psychiatric diagnosis of Antisocial Personality Disorder. Many have major depression, bipolar disorder, and anxiety problems. More than 75 percent smoked cigarettes and marijuana, and many also had cocaine and opiate addictions. More than one-third of these alcoholics seek help for their drinking.

Functional subtype: 19.5 percent of U.S. alcoholics. Typically middle-aged, well-educated, with stable jobs and families. About one-third have a multigenerational family history of alcoholism, about one-quarter had major depressive illness sometime in their lives, and nearly 50 percent were smokers.

Intermediate Familial subtype: 19 percent of U.S. alcoholics. Middle-aged, with about 50 percent from families with multigenerational alcoholism. Almost half have had clinical depression, and 20 percent have had bipolar disorder. Most of these individuals smoked cigarettes, and nearly one in five had problems with cocaine and marijuana use. Only 25 percent ever sought treatment for their problem drinking.

Chronic Severe subtype: 9 percent of U.S. alcoholics. Comprised mostly of middle-aged individuals who had early onset of drinking and alcohol problems, with high rates of Antisocial Personality Disorder and criminality. Almost 80 percent come from families with multigenerational alcoholism. They have the highest rates of other psychiatric disorders including depression, bipolar disorder, and anxiety disorders as well as high rates of smoking, and marijuana, cocaine, and opiate dependence. Two-thirds of these alcoholics seek help for their drinking problems, making them the most prevalent type of alcoholic in treatment.

The authors also report that co-occurring psychiatric and other substance abuse problems are associated with severity of alcoholism and entering into treatment. Attending Alcoholics Anonymous and other 12-step programs is the most common form of help-seeking for drinking problems, but help-seeking remains relatively rare.