Do you know which of your patients have alcohol problems? Though alcohol use disorders may be difficult to detect, self-report and biochemical measures followed by a thorough face-to-face assessment improve diagnostic accuracy. New tools—such as the serum carbohydrate-deficient transferrin (CDT) test—are changing how psychiatrists screen for alcohol problems, provide motivational feedback, and monitor patients for relapse.
FOUR REASONS TO SCREEN
Screening for excessive alcohol consumption is important in psychiatric practice because:
- Alcohol use disorders coexist with many psychiatric problems, most notably affective and anxiety disorders and—not surprisingly—other substance abuse disorders (Table 1).1,2
- Patients with psychiatric comorbidity who abuse alcohol have poorer prognoses, are less adherent to treatment, and are more likely to drop out of treatment than are psychiatric patients who do not have alcohol problems.3
- Alcohol interacts with many psychotropics, and chronic heavy drinking can cause pharmacokinetic changes that affect a patient’s response to medications.
- Alcohol-dependent patients are more likely than nondrinkers to become dependent on anxiolytics and sedative-hypnotics.
Table 1
Overlap of alcohol problems with common psychiatric disorders
| Disorder | Risk of alcohol use disorder (odds ratio) | Source of data (population survey) |
|---|---|---|
| Drug use disorder | 25.1 | NLAES |
| Mania | 5.6 | NCS |
| Major depression | 3.7 | NLAES |
| Obsessive-compulsive disorder | 3.4 | ECA |
| Generalized anxiety disorder | 2.7 | NCS |
| Phobia | 2.3 | NCS |
| Posttraumatic stress disorder | 2.2 | NCS |
| Panic disorder | 1.4 | NCS |
| NLAES: National Longitudinal Alcohol Epidemiological Survey | ||
| NCS: National Comorbidity Survey | ||
| ECA: Epidemiologic Catchment Area | ||
Because alcohol problems are common in psychiatric patients, routine screening for alcohol abuse and dependence at the onset of any treatment can be very useful. Thereafter, screening can be done periodically—perhaps annually or more often if the patient’s functioning declines.
CHOOSING A SELF-REPORT MEASURE
Many self-report alcohol screening scales are available,4 the most popular being the CAGE5 and the Michigan Alcoholism Screening Test (MAST).6 Though both instruments can help identify alcohol problems, each has shortcomings:
- The CAGE performs less reliably in women and adolescents than in men, and its validity depends on the patient’s sensitivity to the emotional impacts of alcohol dependence.
- The MAST is long (25 items), concentrates on late-stage alcoholism symptoms, and uses differential weighting—not validated in subsequent studies—of particular items in deriving the score.
Neither addresses drinking behavior or when symptoms occurred and thus may misclassify recovered alcoholics or former problem drinkers.
AUDIT. A more reliable choice is the Alcohol Use Disorders Identification Test (AUDIT).7 It was designed by the World Health Organization (WHO) to be valid across gender and culture and to identify even early stage problem drinking. The AUDIT’s 10 items deal with drinking behavior, dependence on alcohol, and adverse consequences of drinking during the past year (Box). The survey takes less than 5 minutes; can be administered orally, in writing, or online; and it retains its validity when given as part of a comprehensive health risk appraisal.8
The WHO offers an excellent manual detailing how to administer and interpret the AUDIT (see Related resources). A patient’s score is computed by summing the values associated with his or her responses to each item. A score of 8 or greater indicates excessive alcohol consumption, although some researchers have argued that for women a more accurate threshold might be 6 or 7 points.
Standardized for adults, the AUDIT also appears to accurately gauge drinking behavior in adolescents9 and in psychiatric patients, although only three studies have explored its use in the latter population.10-12 Abbreviated AUDIT versions have been found to be psychometrically sound8 and may be useful in an emergency room or busy primary care clinic. In comparisons with other screening tools, the AUDIT almost always has been found to be more valid.9,13
USING BIOCHEMICAL MEASURES
Self-report screens for alcohol problems, especially the AUDIT, are highly sensitive and specific, though their accuracy depends on the patient's memory, understanding of the questions, and candor. In chronic heavy drinkers, biochemical measures (Table 2) can augment self-reports.14
Self-report and biochemical screens have different strengths and weaknesses (Table 3). It is important to see them as complementary because each contributes to accurate screening.
CDT. Most biomarkers screen indirectly for alcohol problems by measuring damage to an end organ-typically the liver-caused by chronic excessive alcohol consumption. False positive results are common because of nonalcohol-related organ damage, medications, smoking, obesity, and other confounding factors. An exception appears to be the serum test for carbohydrate-deficient transferrin (CDT), a biomarker for heavy drinking approved in kit form 3 years ago by the Food and Drug Administration.
The value of measuring CDT levels is that few conditions other than excessive alcohol consumption elevate them. For unclear reasons,15 average daily consumption of >60 grams of alcohol (about five standard drinks) during the previous 2 weeks causes a higher percent of transferrin—a glycoenzyme that transports iron in the body—to lack its usual carbohydrate content.