Methods of Assessing Alcohol Craving

Psychophysiological and Behavioral Measures
by National Institute of Health

(Page 4 of 5)

Researchers frequently use psychophysiological and behavioral indices in conjunction with self-report measures to elucidate the full range of responses that may relate to craving. A major advantage of measuring these additional response domains is that they provide more objective data than do self-reports and thus may be influenced less by various sources of bias. In addition, many craving theories make specific predictions regarding the physiological responses that should accompany craving reports and the relationships that should be observed across various indices of craving. The assessment of behavioral and psychophysiological variables can help support or disprove these predictions.

In laboratory settings, psychophysiological and behavioral responses are often measured within "cue reactivity" studies, which assume that the subject's responses to alcohol-related stimuli can reflect craving. Cues that have been used in studies of alcohol craving include the sight, smell, and taste of alcohol; pictures or videos of alcohol or alcohol-related scenarios, such as a barroom; the study participant's belief that he or she will consume alcohol; and mental imagery of alcohol-related situations. Negative mood manipulations, which typically involve the participant imagining being in an unpleasant situation or being presented with a stressor that will invoke such a mood, also have been used as a cue for alcohol craving in some studies. Unfortunately, these studies have rarely demonstrated close relationships among behavioral, psychophysiological, and subjective measures of craving. Alcoholics' responses to craving-induction procedures appear to vary considerably as a result of numerous individual differences and situational factors. Nonetheless, cue-reactivity measures have provided valuable information about the correlates of craving. Significantly, some studies have shown that autonomic reactions to alcohol cue presentations, such as changes in skin conductance,3 can predict later relapse to drinking.

Psychophysiological Measures. Several psychophysiological variables have been assessed in response to alcohol cues, including salivation, skin conductance, skin temperature, respiration, heart rate, and blood pressure. Carter and Tiffany recently analyzed the results of numerous studies (conducted a metaanalysis) of cue-reactivity effects on psychophysiological variables across a range of AODs. Consistent with the assumption that alcoholics exhibit increased urges and cravings for alcohol in response to alcohol cues, this analysis revealed that alcoholics across studies demonstrate significant increases in heart rate and skin conductance in response to alcohol cues. That is, most studies showed that alcoholics responded with greater autonomic responses to alcohol cues than to control cues. However, substantial variability existed in the sizes of these effects among the studies included in this analysis, and it is important to note that the effects were generally larger for self-reports of craving than for the psychophysiological signals. The fact that most of these studies included single-item ratings suggests that as alluded to earlier, these items may indeed reliably assess craving in the context of cue-reactivity studies.

One physiological measure that was not included in the meta-analysis by Carter and Tiffany was salivation. Previous reviews have suggested that salivation increases reliably in the presence of alcohol cues. This finding was confirmed in another recent metaanalysis, which also indicated a moderate increase in salivation among alcoholics in response to alcohol cues relative to control cues.

Behavioral Measures. The behavioral measure most closely related to the concept of alcohol craving is alcohol consumption itself. Some researchers consider alcohol seeking and drinking during or after treatment to reflect, at least in part, craving processes. Various direct measures of drinking behavior can serve as outcome variables during or after alcoholism treatment, including frequency of drinking, number of drinks per drinking occasion (drinking intensity), and latency to drink.4 More finegrained behavioral analyses of drinking patterns also have been conducted.

Although researchers generally are reluctant to conduct studies involving alcohol consumption with alcohol-dependent subjects, craving studies performed in laboratory rather than treatment settings occasionally include direct measures of alcohol consumption. For example, Davidson and colleagues recently demonstrated that treatment with the medication naltrexone5 for 1 week diminished overall alcohol consumption and drinking speed in a laboratory session among young heavy drinkers.

Some recent cue-reactivity studies have incorporated indirect behavioral measures in lieu of actual drinking behavior. For example, Tiffany proposed that craving involves mental processes requiring conscious cognitive efforts (nonautomatic cognitive processing) and therefore should interfere with simultaneous activities that also require conscious cognitive effort. To evaluate this hypothesis, Sayette and colleagues randomly assigned 24 alcoholic men admitted for inpatient alcoholism treatment to hold either a glass of water or their preferred alcoholic beverage for 3 minutes and to sniff the contents at specified intervals. Simultaneously, the men were instructed to respond by pressing a button whenever they heard a computer-generated tone. The reaction time on this button-pressing task was considered an indirect marker of the cognitive efforts associated with craving. The study found that during the period when the subjects were asked to sniff the beverages, the men holding the alcoholic beverage exhibited significantly longer reaction times than the men holding a glass of water, suggesting that the men in the alcoholic beverage group experienced greater craving.

Another indirect behavioral measure that may potentially serve as an indicator of alcohol craving is choice cue-viewing time - that is, the length of time a person chooses to look at a stimulus. Within studies on motivation and emotion, choice cue-viewing time has been related to various subjective and physiological indicators of arousal. Several other novel behavioral measurement approaches are currently being developed in the alcohol-craving research arena, some of which borrow methodologies from research on other drugs and from the emotion and motivation research field.

About the Author

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