Screening for Alcohol Problems

What Makes a Test Effective?

Scott H. Stewart, M.D., and Gerard J. Connors, Ph.D.

Screening tests are useful in a variety of settings and contexts, but not all disorders are amenable to screening. Alcohol use disorders (AUDs) and other drinking problems are a major cause of morbidity and mortality and are prevalent in the population; effective treatments are available, and patient outcome can be improved by early detection and intervention. Therefore, the use of screening tests to identify people with or at risk for AUDs can be beneficial. The characteristics of screening tests that influence their usefulness in clinical settings include their validity, sensitivity, and specificity. Appropriately conducted screening tests can help clinicians better predict the probability that individual patients do or do not have a given disorder. This is accomplished by qualitatively or quantitatively estimating variables such as positive and negative predictive values of screening in a population, and by determining the probability that a given person has a certain disorder based on his or her screening results. KEY WORDS: AOD (alcohol and other drug) use screening method; identification and screening for AODD (alcohol and other drug disorders); risk assessment; specificity of measurement; sensitivity of measurement; predictive validity; Alcohol Use Disorders Identification Test (AUDIT)

T he term “screening” refers to the confirm whether or not they have the application of a test to members disorder. When a screening test indicates SCOTT H. STEWART, M.D., is an assistant of a population (e.g., all patients that a patient may have an AUD or professor in the Department of Medicine,

in a physician’s practice) to estimate their other drinking problem, the clinician School of Medicine and Biomedical probability of having a specific disorder, might initiate a brief intervention and Sciences at the State University of New such as an alcohol use disorder (AUD) arrange for clinical followup, which York at Buffalo, Buffalo, New York. (i.e., alcohol abuse or alcohol depen- would include a more extensive diag­ dence). (For a definition of AUDs and nostic evaluation (Babor and Higgins- GERARD J. CONNORS, PH.D., is director other alcohol-related diagnoses, see the Biddle 2001). and a senior research scientist at the sidebar “Definitions of Alcohol-Related Regardless of the context in which Research Institute on Addictions, State Disorders.”) Screening is not the same screening tests are administered and University of New York at Buffalo, as diagnostic testing, which serves to the subsequent responses, it is impor- Buffalo, New York. establish a definite diagnosis of a disor- tant to have an appreciation of the der; screening is used to identify people strengths and limitations of screening Dr. Stewart gratefully acknowledges career who are likely to have the disorder. These tests. Accordingly, the main purpose of development support from the National people are often advised to undergo more this article is to review the characteris- Institute on Alcohol Abuse and Alcoholism detailed diagnostic testing to definitively tics of screening tests that influence (NIAAA) through grant K23–AA–014188.

Vol. 28, No. 1, 2004/2005 5

exist, as defined in two disease classification systems—

pattern of alcohol use leading to clinically significant

criteria for alcohol dependence in the past.

Alcohol dependence is defined as a

time in the same 12-month period:

of the same amount of alcohol.

symptoms.

longer period than was intended.

Alcohol dependence may include physiological

classified as being without physiological dependence.

is defined as a pattern of alcohol use that is causing damage

A variety of terms are used in the scientific literature to describe alcohol use disorders (AUDs) and other condi­ tions characterized by excessive alcohol consumption. AUDs are disorders for which specific diagnostic criteria

the Diagnostic and Statistical Manual of Mental Disorders (DSM), devised by the American Psychiatric Association (APA), and the International Classification of Diseases (ICD), by the World Health Organization (WHO).

DSM Criteria

The most recent version of the DSM, the DSM–IV–TR (APA 2000), includes two AUDs, alcohol abuse and alcohol dependence, which have the following diagnostic criteria:

Alcohol Abuse. Alcohol abuse is defined as a maladaptive

impairment or distress, as manifested by the occurrence of one (or more) of the following within a 12-month period:

• Recurrent alcohol use resulting in a failure to fulfill major role obligations at work, school, or home (e.g., repeated absences or poor work performance related to alcohol use; alcohol-related absences, suspensions, or expulsions from school; neglect of children or household).

• Recurrent alcohol use in situations in which it is physically hazardous (e.g., driving an automobile or operating a machine when impaired by alcohol).

• Recurrent alcohol-related legal problems (e.g., arrests for alcohol-related disorderly conduct).

• Continued alcohol use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of alcohol (e.g., arguments with spouse about intoxication, physical fights).

In addition, the patient must have never met the

Alcohol Dependence. maladaptive pattern of alcohol use leading to clinically significant impairment or distress, as manifested by the occurrence of three (or more) of the following at any

• Tolerance, as defined by either of the following:

– A need for increased amounts of alcohol to achieve intoxication or the desired effect.

– Markedly diminished effect with continued use

• Withdrawal, as manifested by either of the following:

– The characteristic withdrawal syndrome.

– Use of alcohol to relieve or avoid withdrawal

• Drinking alcohol often in larger amounts or over a

• A persistent desire or unsuccessful efforts to cut down or control alcohol use.

• A great deal of time spent in activities necessary to obtain alcohol, use it, or recover from its effects.

• Giving up or reducing important social, occupa­ tional, or recreational activities because of alcohol use.

• Continued alcohol use despite having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by alcohol (e.g., continued drinking despite recognition that an ulcer was made worse by alcohol consumption).

dependence if there is evidence of tolerance or withdrawal. If neither of these is present, alcohol dependence is

ICD Criteria

The most recent version of the ICD, ICD–10 (World Health Organization 1993), distinguishes between harm­ ful use and alcohol dependence syndrome. Harmful use

to health. The damage may be physical (e.g., hepatitis following long-term alcohol use) or mental (e.g., depressive episodes secondary to heavy alcohol intake). Harmful use commonly, but not invariably, has adverse social

Definitions of Alcohol-Related Disorders

Alcohol Research & Health 6

Screening for Alcohol Problems

harmful use.

within a 12-month period:

alcohol.

longer period than intended.

drawal symptoms.

effect.

use of the same amount of alcohol.

harm.

ICD–10.

These terms can differ in their meanings and generally

American Psychiatric Association (APA). Diagnostic and Statistical Manual Washington, DC: APA,

2000.

World Health Organization (WHO). International Statistical Classification Geneva,

Switzerland: WHO, 1993.

consequences; social consequences in themselves, however, are not sufficient to justify a diagnosis of

The ICD criteria for alcohol dependence syndrome are very similar to those for alcohol dependence in the DSM–IV–TR. They specify that three or more of the following manifestations should have occurred together for at least 1 month or, if persisting for periods of less than 1 month, should have occurred together repeatedly

• A strong desire or sense of compulsion to consume

• Impaired capacity to control drinking in terms of its onset, termination, or levels of use, as evidenced by either of the following:

– Alcohol often taken in larger amounts or over a

– A persistent desire or unsuccessful efforts to reduce or control alcohol use.

• A physiological withdrawal state when alcohol is reduced or ceased, as evidenced by either of the following:

– The characteristic withdrawal syndrome for alcohol.

– Use of the same (or closely related) substance with the intention of relieving or avoiding with­

• Evidence of tolerance to the effects of alcohol, such that one of the following occurs:

– A need for significantly increased amounts of alcohol to achieve intoxication or the desired

– A markedly diminished effect with continued

• Preoccupation with alcohol, as manifested by one of the following:

– Giving up or reducing important alternative pleasures or interests because of drinking.

– Spending a great deal of time in activities necessary to obtain or consume alcohol, or to recover from its effects.

• Persistent alcohol use despite clear evidence of harmful consequences, as evidenced by continued use when the person is actually aware, or may be expected to be aware, of the nature and extent of

In addition to the diagnosis of alcohol dependence, the World Health Organization also uses the term “haz­ ardous use,” which describes a pattern of substance use that increases the risk of harmful consequences for the user. These may include not only physical and mental health consequences but also social consequences. In contrast to harmful use, hazardous use refers to patterns of use that are of public health significance but do not meet the criteria for a current disorder in the drinker. However, the term is not a diagnostic term in the

Other Terms Used

In addition to these specific diagnostic terms, various other terms are used in the literature, such as problem drinking, at-risk drinking, and problematic drinking.

are defined in the context of the specific study.

—Scott H. Stewart and Gerard J. Connors

References

of Mental Disorders. Fourth Edition, Text Revision.

of Diseases and Related Health Problems. Tenth Revision.

Vol. 28, No. 1, 2004/2005 7

their usefulness in clinical settings. This includes their validity, sensitivity, and specificity. In addition, the article dis­ cusses methods to quantify the likeli­ hood that a patient with a given screen­ ing result actually has the disorder (i.e., the postscreen probability). A review of different screening tests, particularly those that can be used in specific settings or with special populations, is beyond the scope of this article. The accompa­ nying table summarizes the features of some of the most commonly used screening instruments. Additional screening tools and their characteristics have been reviewed by Connors and Volk (2003) and are described in the other articles in this issue and the companion issue of Alcohol Research & Health.

What Disorders Are Amenable to Screening?

Not all disorders are suitable for screening; in fact, for certain disorders, screening tests may not be helpful or desirable. The main goal of screening is to identify patients at risk for a given disorder or at early stages of the disorder, so that they can begin to receive effective treatment and avoid or ameliorate the morbidity and mortality associated with the disor­ der. Consequently, disorders should have the following characteristics to be considered suitable for screening:

• They should be a cause of substantial morbidity or mortality.

• Effective treatment should be available that leads to a measurable improvement in morbidity and mor­ tality compared with no treatment.

• Early treatment initiated after a positive screening result should lead to a better outcome than treatment which is initiated later in the disease process, when the disease has pro­ duced obvious symptoms that have led to a diagnosis. For example, in a general medical setting, patients should have better outcomes if an intervention is initiated after a

screening test, such as the Alcohol Use Disorders Identification Test (AUDIT) (Babor et al. 2001), suggests a pattern of “harmful drinking” than if a diagnosis is made and intervention started after the patient already has devel­ oped a more severe condition, such as alcoholic liver disease.

• The disorder should be relatively common because, all else being equal, screening for prevalent disorders is more cost-effective than screening for rare disorders.

AUDs and other drinking problems generally fit these criteria. They are a major cause of morbidity and mortality (NIAAA 2000), are prevalent in the population (NIAAA 2003), and effective treatments are available (Saitz 2005). In addition, because AUDs may have an acute presentation (e.g., alcohol-related trauma or gastrointestinal bleeding) or

result in long-term adverse consequences (e.g., liver disease) patients benefit from early detection and intervention. Finally, many people with AUDs never are diagnosed correctly. The next sections therefore will explore the characteristics screening tests must possess in order to be useful and effective.

Characteristics of Screening Tests Affecting Their Usefulness

Screening tests are designed to be used with members of large populations who have no obvious signs of a particular disease or disorder. For detecting AUDs and other alcohol-related problems, screening may involve the use of biological markers (e.g., liver tests or measurement of a compound called carbohydrate- deficient transferrin) (see Allen et al. 2003) or self-report questionnaires (e.g., the AUDIT, CAGE, and others).

Common Alcohol Screening Instruments in Medical Settings*

Population to Number of Items Time to Administer Measure Be Screened (Subscales) (Minutes)

Alcohol Use Adults 10 (3) 2 Disorders Identification Test (AUDIT)

CAGE Adults and 4 <1 Questionnaire adolescents > 16 years

Michigan 25 8 Alcoholism adolescents Screening Test (MAST)

Self- Adults 35 (2) 5 Administered Alcoholism Screening Test (SAAST)

* Briefer versions of some of these screening instruments (e.g., the MAST and SAAST) also have been tested.

SOURCE: National Institute on Alcohol Abuse and Alcoholism (NIAAA). Assessing Alcohol Problems: A Guide for Clinicians and Researchers, 2d ed. NIH Pub. No. 03–3745. Washington, DC: U.S. Dept. of Health and Human Services, Public Health Service, 2003.

Adults and

Alcohol Research & Health 8

Screening for Alcohol Problems

Because screening large numbers of people comes at a cost, the screening test should be considered beneficial from the perspective of the society in which it is applied. This means that the test either saves more resources than it utilizes or that the benefits resulting from the screen are perceived to outweigh the cost. Cost-effectiveness is thus determined by factors such as the disease character­ istics discussed above, the direct costs of the screening test, the safety of the test, and the validity of the screening test. Validity refers to the screening test’s ability to distinguish those at greater risk for a disorder from those at lower risk. In the development of screening tests, validity is quantified by comparing screening results with a gold standard for diagnosis.

Validity and the Gold Standard