Inducing Craving for Alcohol in the Laboratory

Alcohol Research & Health, Fall, 1999 by Mark D. Litt, Ned L. Cooney

Research on the mechanisms of craving often involves inducing craving in subjects in controlled settings. This article describes techniques that have been used to induce craving for alcohol, including (1) exposing subjects to actual alcoholic beverages, (2) exposing subjects to visual representations of alcoholic beverages, (3) manipulating the subjects' mood states, and (4) controlling environmental settings. The intensity of craving can be rated by the subjects themselves or can be assessed by clinicians through behavioral observations or the measurement of certain physiological responses. Success in inducing craving in the laboratory, however, has been inconsistent. Ultimately, researchers may need to monitor subjects' craving responses in actual environmental settings. KEY WORDS: AOD (alcohol and other drug) craving; alcohol cue; relapse prevention; laboratory measurement; classical conditioning; treatment model; prevention research; AOD use behavior; empirical study; expectancy; visual perception; psycho logical AODC (causes of alcohol and other drug use); biological AODC; emotion; laboratory study; literature review; context dynamics

Many researchers and clinicians consider craving for alcohol a precursor to relapse among alcoholics in treatment (Marlatt and Gordon 1985). The role of craving in relapse is controversial, however, and research on the subject is hampered by the lack of a generally accepted definition of craving. Rankin and colleagues (1979) defined craving as a "central state," synonymous with a desire or disposition to drink alcohol. Using this approach, craving can be considered a motivational state (i.e., a condition that increases the probability of seeking and consuming alcohol or other drugs [AODs]). This does not imply, however, that craving always leads to drinking. Although this definition lacks precision to some extent, it has the advantage of differentiating craving from intention, expectancies, or automatic behaviors (i.e., "habit") (see the article in this issue by Rohsenow and Monti, pp. 225-232).

Craving may be triggered by exposure to an object, environment, or emotion that a person has come to associate with alcohol consumption. Such stimuli are called alcohol-related cues (ARCs). Ludwig and colleagues (1974) suggested that the ability of ARCs to elicit craving may be acquired through a learning process called classical conditioning (see sidebar by Tiffany, p. 216). This form of learning occurs when a stimulus that would not normally elicit any particular response (i.e., a neutral stimulus) is repeatedly associated, or paired, with a stimulus that does elicit a specific response. The previously neutral stimulus is referred to as a cue. Thus, exposure to ARCs may eventually elicit mental, behavioral, and physiological reactions similar to those evoked by the actual consumption of alcohol or by withdrawal. [1] Such cues may include the sight or smell of an alcoholic beverage; the familiar surroundings of a favorite bar; or the onset of an emotional state, such as anger or depression, that a person is accustomed to reacting to by drinking.

Some researchers have explored the possibility of diminishing craving by repeatedly exposing subjects to ARCs without permitting them to drink (Laberg 1990). Proponents of this approach purport that the procedure can diminish and eventually abolish craving by weakening the association between cue and response.

Research on the mechanisms of craving is required to improve our understanding of the development of alcoholism and to support treatment and prevention efforts. Therefore, researchers have developed techniques to induce craving for alcohol in controlled settings. This article briefly reviews techniques for measuring craving and describes approaches to inducing craving that use the following strategies: (1) exposing subjects to actual alcoholic beverages, (2) exposing subjects to visual representations of alcoholic beverages, (3) manipulating subjects' mood states, and (4) controlling environmental settings.

MEASURING CRAVING

Craving can be measured directly by asking subjects to rate the strength of their urge to drink or indirectly by observing subjects' behavior in response to ARCs or to the consumption of alcohol itself. Craving can also be assessed indirectly by measuring certain physiological responses that appear to accompany craving, such as increased salivation and swallowing. Other measurable physiological responses include changes in heart rate and in the electrical properties of the skin surface. (See the article in this issue by Drobes and Thomas, pp. 179-186, for a review of the applications, advantages, and disadvantages of techniques for measuring craving.)

EXPOSURE TO ALCOHOLIC BEVERAGES

The first attempts to elicit craving in the laboratory involved the presentation of those cues considered most likely to evoke an appropriate response (i.e., the most salient cues) (Laberg 1990). In the most basic application of this approach, the experimenter places a standard alcoholic drink on a table in front of the subject and instructs the subject to look at the beverage, hold it (at arm's length in some studies), and sniff it repeatedly. To minimize the possibility of provoking relapse, researchers usually instruct alcohol-dependent subjects not to drink the beverage and provide them with no opportunity to consume it.