Inducing Craving for Alcohol in the Laboratory : Part 2

by National Institute of Health

(Page 2 of 3)

The most successful means of eliciting craving in the laboratory is to present a subject with alcohol and allow him or her to consume it. Although the subject may be urged to resist drinking if possible, the subject must be informed that he or she will not be prevented from drinking. In a series of experimental sessions conducted over a period of 4 months, Laberg compared the effects on alcoholic subjects of an initial (priming) dose of an alcoholic beverage (vodka) or a "soft drink". Experimenters measured each subject's self-reported cravings as well as his or her behavioral and physiological responses three times during the study: when the subject was told he or she would receive alcohol, when the subject consumed the priming dose, and when the subject was offered two extra drinks 45 minutes after consuming the priming dose (the drinking test). At each session, one-half of the subjects who had been told that they were to receive alcohol were actually given water with one drop of vodka on the rim of the bottle. Similarly, one-half of the subjects who had been told they were to receive a nonalcoholic drink were given alcohol.

In these studies, the rates of craving reactivity among alcoholics were high. Interestingly, the self-reports of alcohol craving by alcoholic subjects were influenced more by whether a subject believed that the priming drink was alcoholic or nonalcoholic than by the drink's actual contents. These studies suggest that the promise, or expectancy, of a future alcoholic drink is a potent cue for craving, especially when a drink has already been consumed.

Although the combination of priming and expectancy induces craving responses, the approach presents conceptual difficulties, both as an experimental procedure and as a potential component of treatment programs. Conceptually, craving poses the greatest threat to recovering alcoholics who are currently abstinent. Allowing subjects a priming dose of alcohol in the laboratory provides no information on factors that influence consumption of a person's first drink; rather, these procedures explore the effects of craving on further alcohol consumption after drinking is initiated. Some clinicians have suggested that offering alcohol to a person who has been trying to abstain might counteract the effects of therapy. However, many researchers have safely administered alcohol in experimental settings to selected, wellsupervised subjects who have been informed of the risks and benefits involved, as in any other type of medical research.

Yet the presentation of alcohol cues alone, even of a favored beverage mixed in front of a subject, has not always proven to be a salient stimulus. Additionally, if laboratory craving is to be considered an analog for craving in the natural environment, then craving reactivity should predict drinking behavior outside the laboratory. Reactivity to alcohol cues has predicted relapse in some studies but not in others. Evidence indicates that alcohol cues alone may not be sufficiently salient to elicit craving from many alcoholics in the absence of an opportunity to consume.

Exposure to Alcohol Related Visual Images

Because visual representations of alcohol are ubiquitous in our society (in advertisements and storefronts), it is reasonable to examine reactivity in response to the presentation of purely visual stimuli. Although visual stimuli have been used to elicit reactivity in drug abusers, such cues have rarely been employed to study alcoholism. In one study, alcoholic subjects who had viewed slides of alcohol-related subject matter (liquor stores, alcoholic beverage containers, and scenes of people consuming alcoholic beverages) reported significantly greater increases in subjective alcohol craving and anxiety levels than did alcoholic subjects who had viewed slides of non-alcohol-related subject matter (a row of storefronts or scenes of people drinking milk, tea, or coffee). Physiological measures did not differ between groups of subjects viewing the two sets of slides. No data relating reactivity to later drinking were reported.

Cassisi and colleagues measured the physiological responses of nonalcoholic social drinkers who viewed slides depicting alcohol- and nonalcohol- related beverage advertisements from popular magazines. Lighter drinkers (drinkers who consumed an average of two alcoholic beverages per week) tended overall to show significant decreases in heart rate in response to both types of slides, an orienting response to incoming information regardless of its content. Heavier drinkers (drinkers who consumed 16 or more alcoholic beverages per day) overall showed no change in heart rate but demonstrated increased skin conductance, indicating activation of the nervous system characteristic of anxiety. This finding is consistent with decisionmaking-focused theories, postulating that urges reflect a conflict between "motivation to use" and "intention to stay abstinent".

In general the few studies that have relied solely on visual cues to elicit craving have produced conflicting findings, and no study has linked visual cue reactivity to subsequent drinking behavior. Thus, visual cues alone are probably not sufficiently salient for research purposes.

Alteration of Mood State

Much of the research on cue reactivity in alcoholics has focused on external cues, primarily the sight or smell of alcoholic beverages. It has become increasingly apparent that internal cues, such as mood states, can also elicit the desire for alcohol if, for example, a person habitually drinks alcohol when in a particular mood. Alcoholics have often reported that their relapses occurred during negative mood states, such as depression, anger, or interpersonal stress. In addition, depression and anger have been shown to trigger opiate craving as well as symptoms similar to those of withdrawal in abstinent opiate abusers.

Occasionally, videotapes have been used in studies of alcohol craving to induce desired moods. This type of research is typically conducted by showing subjects film excerpts that have been independently rated as inducing specific mood states - for example, joy (The Sound of Music), disgust (Dawn of the Dead), or anger. Cooney and colleagues presented a brief review of the way in which the manipulation of mood states is used in alcoholism research. The basic procedure often involves interviewing the participant about his or her recent drinking history (a relapse), with an emphasis on eliciting information about the person's mood states during these episodes. The participants are asked to relate the experience in as much detail as possible. A so-called guided imagery script is then prepared incorporating the details from that event, including strong and frequent inducements to cause the person to experience the same mood as in the original incident. This script is usually read to the person while he or she is in a relaxed but attentive state, before or during the presentation of a preferred alcoholic beverage or exposure to an ARC. Mood ratings, as well as craving ratings, are taken to ensure that the appropriate mood is induced.

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