Inducing Craving for Alcohol in the Laboratory : Part 3

by National Institute of Health

(Page 3 of 3)

In an initial trial of mood induction to elicit craving, Litt and colleagues employed scripts in which mood state alone was suggested without including any mention of use or presence of alcohol or alcohol cues. Both positive and negative moods were induced using a hypnotic induction procedure. Results indicated that negative mood alone was sufficient to elicit the desire to drink in five of eight of the subjects but that alcoholic beverage presentation alone did not elicit craving. Relaxation accompanying hypnotic induction may have been sufficient to dampen the subjects' responses to alcohol cues in the absence of the arousing mood states that tend to stimulate alcohol-seeking behavior. Thus, procedures that elicit deep relaxation may not be optimal for eliciting high rates of craving.

More recently, investigators have administered to subjects guided imagery scripts that essentially recreate relapse episodes, complete with whatever beverage cues the subjects encountered during their original episodes. The most effective mood states for inducing craving are consistently negative ones, often involving high arousal, as in anger or anxiety. The use of such high-emotion, high-risk scripts has produced relatively high reactivity rates in subjects, which in turn have sometimes been shown to predict relapse. To date, guided imagery procedures have proven to be the most effective and efficient means to elicit reports of craving, although more effective means may be available.

Manipulating the Setting

Laboratory studies of craving have often been criticized because of the artificial nature of the drinking environment. Thus, subjects consuming alcohol in the controlled setting of a hospital or laboratory are less likely to experience the "loss of control" that may occur when they drink in their homes or in their favorite bars. Studies in which drinking is not allowed provide an even more artificial environment for inducing craving. Such studies, which are often located in a treatment setting, may actually inhibit craving (or at least reported craving) in alcoholics who are attempting to remain abstinent.

Some investigators have attempted to gain the advantages of a realistic drinking setting in the controlled laboratory environment by recreating a barroom in the laboratory, complete with bartender. The alcoholic beverage is mixed in front of the subject, and he or she is free to pick up the drink, sniff it and, in some circumstances, drink it. The intention is to decrease the inhibiting effect seen in the laboratory and to add as many relevant stimulus cues for drinking as possible, including the sight and smell of alcoholic beverages.

Laberg has reported significant rates of craving in simulated barroom settings, but these rates have been obtained by allowing alcohol consumption, often in the form of a priming dose. A few studies have been conducted using simulated barrooms with alcoholics in which alcohol consumption has not been allowed.

In one effort to examine elements that contribute to the stimulus value of a setting that might further induce craving, Sher arranged for social drinkers (those who consume at least two drinks per week) to be served either a nonalcoholic drink or an alcoholic drink either alone or in a group setting in a room designed to resemble a lounge with a bar and bartender. The presence of a group of drinkers appeared to interact with the barlike setting to increase the positive mood and the perceived pleasurable physical sensations in response to the beverage. Indeed, the subjects who consumed a neutral beverage in a group setting reported physical sensations similar to those reported by subjects who had consumed alcohol. The implication of this study for laboratory craving research is that approximating the setting in which the subject usually drinks, including the social context (a group setting), may be useful in enhancing the craving response. However, a reading of the existing studies suggests that without the subject having some expectation of being able to consume alcohol, these manipulations may not be sufficient to reliably elicit craving.

Conclusions

The idea that a cue-exposure procedure in the laboratory can be used to study craving is so appealing that dozens of investigators have produced studies on the topic. Theoretically, it would seem simple to construct a stimulus that would elicit craving, even in a controlled setting like a laboratory. Yet, for the most part, success in inducing craving in the laboratory has been inconsistent. Although most studies report that aggregate desire for alcohol increases with exposure to various stimuli, few studies report the percentage of subjects that experience an increase in craving. Those studies that include percentages typically report that only about 50 to 66 percent of the subjects experience an increase in craving. The induction procedures that have proven most successful thus far are those that employ guided imagery to expose the subject to as many alcohol-related cues as possible, both external and internal, while suggesting, through the use of carefully worded instructions, some possibility that the person may drink if absolutely necessary.

Although guided imagery techniques have shown some promise in eliciting craving in subjects, they are nevertheless problematic. The relaxation that inevitably takes place in such procedures may act to dampen craving reactivity while the imagery simultaneously encourages reactivity. Furthermore, the nature of the guided imagery task is such that experimenter demand for reporting craving is maximized. That is, in some guided imagery studies, subjects are explicitly instructed to experience craving and are then asked to report if they really experience craving or not. Given these instructions, participants may feel obliged to report craving even if they do not feel it. Finally, few studies have sought to validate the cue reactivity found in the laboratory by linking reactivity to actual drinking behavior.

For the craving-induction procedure to function as a laboratory model of high-risk situations outside of the laboratory setting, a connection should exist between reactivity elicited in the laboratory and subsequent drinking behavior. Some evidence for this connection has been found using guided imagery inductions, but the results overall are mixed, with several studies reporting no relation between reactivity in the laboratory and drinking after treatment. To conduct valid craving studies, investigators must demonstrate more than just self-reported or physiological reactivity in the laboratory.

Setting manipulations, such as simulating barrooms, complete with bartenders and fellow drinkers, and preferably located away from the usual laboratory environment, may provide a sufficiently stimulating environment to overcome the artificiality of the situation. In the meantime, guided imagery inductions remain the most efficient means for trying to induce craving without encouraging drinking. It may be the case, however, that no laboratory model of craving will prove adequate to capture the phenomenon that alcoholics say they experience. Ultimately, researchers may need to study alcoholics within their home environments and monitor their perceptions in order to provide the basis for a universally accepted definition of craving.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.