James G. Murphy

Relative Efficacy of a Brief Motivational Intervention for College Student Drinkers

The authors evaluated the efficacy of Brief Alcohol Screening and Intervention for College Students (BASICS - L. A. Dimeff, J. S. Baer, D. R. Kivlahan, & G. A. Marlatt, 1999), a single session of drinking-related feedback intended to reduce heavy drinking and related harm. College student drinkers (N = 99) were assigned to BASICS, an educational intervention, or an assessment-only control group. At 3 months postintervention. there were no overall significant group differences, but heavier drinking BASICS participants showed greater reductions in weekly alcohol consumption and binge drinking than did heavier drinking control and education participants. At 9 months, heavier drinking BASICS participants again showed the largest effect sizes. BASICS participants evaluated the intervention more favorably than did education participants. This study suggests that BASICS may be more efficacious than educational interventions for heavier drinking college students.

Relative reinforcing efficacy of alcohol among college student drinkers.

The construct of relative reinforcing efficacy (RRE) is central to many laboratory and theoretical models of drug abuse, but it has not been widely measured in applied clinical research contexts. The authors used a simulated alcohol purchase task to measure RRE in a sample of 267 college student drinkers. Participants reported their alcohol consumption across a range of prices, and their responses were well-described by a regression equation that has been used to construct demand curves in drug self-administration studies. Several measures of relative reinforcing efficacy were generated, including breakpoint, intensity of demand, elasticity, P-sub(max) (price at which response output is maximized), and O-sub(max) (maximum alcohol expenditures). Demand for alcohol was inelastic across the initial range of prices but became elastic as price increased. Students who reported recent heavy drinking reported significantly greater intensity of demand, O-sub(max), and breakpoint. These results provide initial support for the validity of the RRE indices generated with the alcohol purchase task. These results also provide empirical support for programs that attempt to reduce alcohol abuse by eliminating low-cost access to alcohol.

Alcohol demand, delayed reward discounting, and craving in relation to drinking and alcohol use disorders

A behavioral economic approach to alcohol use disorders (AUDs) emphasizes both individual and environmental determinants of alcohol use. The current study examined individual differences in alcohol demand (i.e., motivation for alcohol under escalating conditions of price) and delayed reward discounting (i.e., preference for immediate small rewards compared to delayed larger rewards) in 61 heavy drinkers (62% with an AUD). In addition, based on theoretical accounts that emphasize the role of craving in reward valuation and preferences for immediate rewards, craving for alcohol was also examined in relation to these behavioral economic variables and the alcohol-related variables. Intensity of alcohol demand and delayed reward discounting were significantly associated with AUD symptoms, but not with quantitative measures of alcohol use, and were also moderately correlated with each other. Likewise, craving was significantly associated with AUD symptoms, but not with alcohol use, and was also significantly correlated with both intensity of demand and delayed reward discounting. These findings further emphasize the relevance of behavioral economic indices of motivation to AUDs and the potential importance of craving for alcohol in this relationship.

The Behavioral Economics of Substance Use Disorders: Reinforcement Pathologies and Their Repair

The field of behavioral economics has made important inroads into the understanding of substance use disorders through the concept of reinforcer pathology. Reinforcer pathology refers to the joint effects of (a) the persistently high valuation of a reinforcer, broadly defined to include tangible commodities and experiences, and/or (b) the excessive preference for the immediate acquisition or consumption of a commodity despite long-term negative outcomes. From this perspective, reinforcer pathology results from the recursive interactions of endogenous person-level variables and exogenous environment-level factors. The current review describes the basic principles of behavioral economics that are central to reinforcer pathology, the processes that engender reinforcer pathology, and the approaches and procedures that can repair reinforcement pathologies. The overall goal of this review is to present a new understanding of substance use disorders as viewed by recent advances in behavioral economics.

PTSD symptoms, hazardous drinking, and health functioning among U.S.OEF and OIF veterans presenting to primary care

Posttraumatic stress disorder (PTSD) and alcohol abuse both are negatively associated with health, and alcohol misuse may mediate the relationship between PTSD and functional health outcomes. The present study tested for such mediation using self-report measures of PTSD symptoms, hazardous alcohol use, and health functioning in 151 U.S. veterans (136 men and 15 women) of the wars in Iraq and Afghanistan recruited from a Veterans Affairs primary care clinic. Based on established cut scores, 39.1% screened positive for PTSD and 26.5% screened positive for hazardous drinking. PTSD symptoms and hazardous drinking were significantly correlated with each other and with health functioning. Hazardous drinking was found to partially mediate the relationship between PTSD and functional mental health, but not physical health.

Further validation of a cigarette purchase task for assessing the relative reinforcing efficacy of nicotine in college smokers.

The authors sought to further validate a cigarette purchase task (CPT), a self-report analogue of a progressive-ratio operant schedule, for the assessment of the relative reinforcing efficacy (RRE) of nicotine in smokers. The measure was assessed in terms of its correspondence to typically observed operant behavior, convergent validity, and divergent validity. Participants were 33 individuals (58% male, age M = 19.30 years) who smoked at least weekly (M = 5.31 cigarettes/day) and underwent a single assessment session. Data from the CPT exhibited the predicted inverse relationship between consumption and price, the predicted relationship between consumption and expenditure, and a heterogeneous pattern of interrelationships among the indices of reinforcement. In addition, 2 indices from the measure, intensity of demand and maximum expenditure for cigarettes, exhibited robust convergent and divergent validity. Although this is an incipient research area and the current study used a relatively small sample, these findings support the validity of a CPT as a time- and cost-efficient method for assessing nicotine reinforcement. Theoretical implications of the findings, limitations, and future directions are also discussed.

Using Behavioral Theories of Choice to Predict Drinking Outcomes Following a Brief Intervention.

Behavioral theories of choice predict that substance use is partly a function of the relative value of drugs in relation to other available reinforcers. This study evaluated this hypothesis in the context of predicting drinking outcomes following an alcohol abuse intervention. Participants (N = 54, 69% female, 31% male) were college student heavy drinkers who completed a single-session motivational intervention. Students completed a baseline measure of substance-related and substance-free activity participation and enjoyment. Only women showed a significant reduction in drinking at the 6-month follow-up, and the ratio of substance-related to substance-free reinforcement accounted for unique variance in their drinking outcomes. Women who at baseline derived a smaller proportion of their total reinforcement from substance use showed lower levels of follow-up drinking, even after the authors controlled for baseline drinking level. Male and female participants who reduced their drinking showed increased proportional reinforcement from substance-free activities.

Associations between depression, distress tolerance, delay discounting, and alcohol-related problems in European American and African American college students

Although levels of heavy drinking and alcohol-related problems are high in college students, there is significant variability in the number and type of problems experienced, even among students who drink heavily. African American students drink less and experience fewer alcohol-related problems than European American students, but are still at risk, and little research has investigated the potentially unique patterns and predictors of problems among these students. Depression, distress tolerance, and delay discounting have been implicated in adult substance abuse and may be important predictors of alcohol problem severity among college students. We examined the relationship between these variables and alcohol-related problems among African American and European American students (N = 206; 53% female; 68% European American; 28% African American) who reported recent heavy drinking. In regression models that controlled for drinking level, depression, distress tolerance, and delay discounting were associated with alcohol problems among African American students, but only depression was associated with alcohol problems among European American students. These results suggest that negative affect is a key risk factor for alcohol problems among college student drinkers. For African American students, the inability to tolerate negative emotions and to organize their behavior around future outcomes may also be especially relevant risk factors.

Behavioral economic analysis of cue-elicited craving for alcohol

AIMS Craving as a motivational determinant of drug use remains controversial because of ambiguous empirical findings. A behavioral economic approach may clarify the nature of craving, theorizing that subjective craving functionally reflects an acute increase in a drugs value. The current study tested this hypothesis via a multidimensional assessment of alcohol demand over the course of an alcohol cue reactivity procedure. DESIGN One-way within-subjects design. SETTING Human laboratory environment. PARTICIPANTS Heavy drinkers (n = 92) underwent exposures to neutral (water) cues followed by personalized alcohol cues. ASSESSMENTS Participants were assessed for craving, alcohol demand, affect, and salivation following each exposure. FINDINGS Alcohol versus neutral cues significantly increased craving and multiple behavioral economic measures of the relative value of alcohol, including alcohol consumption under conditions of zero cost (intensity), maximum expenditure on alcohol (O(max)), persistence in drinking to higher prices (breakpoint) and proportionate price insensitivity (normalized P(max)). Craving was significantly correlated with demand measures at levels ranging from 0.21-0.43. CONCLUSIONS These findings support the potential utility of a behavioral economic approach to understanding the role of environmental stimuli in alcohol-related decision making. Specifically, they suggest that the behavioral economic indices of demand may provide complementary motivational information that is related to though not entirely redundant with measures of subjective craving.

Is Talk “Cheap”? An Initial Investigation of the Equivalence of Alcohol Purchase Task Performance for Hypothetical and Actual Rewards

BACKGROUND Behavioral economic alcohol purchase tasks (APTs) are self-report measures of alcohol demand that assess estimated consumption at escalating levels of price. However, the relationship between estimated performance for hypothetical outcomes and choices for actual outcomes has not been determined. The present study examined both the correspondence between choices for hypothetical and actual outcomes, and the correspondence between estimated alcohol consumption and actual drinking behavior. A collateral goal of the study was to examine the effects of alcohol cues on APT performance. METHODS Forty-one heavy-drinking adults (56% men) participated in a human laboratory protocol comprising APTs for hypothetical and actual alcohol and money, an alcohol cue reactivity paradigm, an alcohol self-administration period, and a recovery period. RESULTS Pearson correlations revealed very high correspondence between APT performance for hypothetical and actual alcohol (ps < 0.001). Estimated consumption on the APT was similarly strongly associated with actual consumption during the self-administration period (r = 0.87, p < 0.001). Exposure to alcohol cues significantly increased subjective craving and arousal and had a trend-level effect on intensity of demand, in spite of notable ceiling effects. Associations among motivational indices were highly variable, suggesting multidimensionality. CONCLUSIONS These results suggest there may be close correspondence both between value preferences for hypothetical alcohol and actual alcohol, and between estimated consumption and actual consumption. Methodological considerations and priorities for future studies are discussed.