Behavioral Impulsivity Does Not Predict Naturalistic Alcohol Consumption or Treatment Outcomes.

OBJECTIVE: The purpose of this study was to determine if behavioral impulsivity under multiple conditions (baseline, after alcohol consumption or after serotonin depletion) predicted naturalistic alcohol use or treatment outcomes from a moderation-based contingency management intervention. METHOD: The current data analysis pulls information from three phases of a large study: 1) Phase 1 examined baseline and the effects of alcohol use and serotonin depletion on three types of behavioral impulsivity: response initiation (IMT task), response inhibition (GoStop task), and delay discounting (SKIP task); 2) Phase 2 involved 28 days of naturalistic drinking; and 3) Phase 3 involved 3 months of contingency management. During phases 2 and 3 alcohol use was measured objectively using transdermal alcohol monitors. The results of each individual phase has been previously published showing that at a group level the effects of alcohol consumption on impulsivity were dependent on the component of impulsivity being measured and the dose of alcohol consumed but serotonin depletion had no effect on impulsivity, and that a moderation-based contingency management intervention reduced heavy drinking. RESULTS: The current analysis combining data from those who completed all three phases (n = 67) showed that impulsivity measured at baseline, after alcohol consumption, or after serotonin depletion did not predict naturalistic drinking or treatment outcomes from a moderation-based CM treatment. CONCLUSIONS: Contingency management interventions may prove to be an effective intervention for impulsive individuals, however, normal variations in measured impulsivity do not seem to relate to normal variations in drinking pattern or response to moderation-based contingency management.

The Potential Clinical Utility of Transdermal Alcohol Monitoring Data to Estimate the Number of Alcoholic Drinks Consumed.

OBJECTIVES: Transdermal alcohol monitoring is used extensively in forensic settings to identify whether individuals have violated court-ordered mandates to abstain from drinking. Despite widespread use in that setting, comparatively few studies have explored the clinical utility of transdermal alcohol monitoring. Furthermore, of the few studies conducted, most have relied on the forensically established conservative criteria to identify whether or not a drinking episode has occurred. Here, we explore how transdermal alcohol monitoring data can be used to estimate more clinically meaningful parameters relevant to clinical treatment programs. METHODS: We developed a procedure to use transdermal data to objectively estimate the number of standardized drinks an individual has consumed. Participants included 46 men and women who consumed 1 to 5 beers within 2 hours in the laboratory on separate days while wearing devices to monitor transdermal alcohol concentrations (TAC). RESULTS: A mathematical model was derived to estimate the number of standardized alcohol drinks consumed, which included a number of variables (time-to-peak TAC, area under the TAC curve, and sex). The model was then validated by applying it to data from a separate study. Our results indicate that transdermal alcohol devices can be used to estimate the number of standard drinks consumed. CONCLUSIONS: Objective methods characterizing both the level of intoxication achieved and the number of drinks consumed, such as transdermal alcohol monitoring, could be useful in both research and treatment settings.

Using Transdermal Alcohol Monitoring to Detect Low-Level Drinking.

BACKGROUND: Several studies demonstrate the utility of Alcohol Monitoring Systems' (AMS) transdermal alcohol concentration (TAC) monitor to objectively quantify drinking. AMS standard criteria (i.e., TAC >0.02 g/dl) used for drinking detection are deliberately conservative, but consequently only detect drinking equivalent to 5 or more standard drinks. Our study sought to characterize the sensitivity of TAC measurement to detect low-level drinking defined as the consumption of 1 to 3 beers. METHODS: Data were pooled from 3 studies giving controlled doses of 1, 2, 3, 4, and 5 Corona© beers (12 oz = 0.92 standard units) to 32 male and 29 female research volunteers wearing TAC monitors under controlled conditions. Analyses describe the sensitivity to detect drinking at various peak TAC thresholds beginning with any positive reading >0 g/dl, and then using TAC thresholds of 0.02 and 0.03 g/dl. RESULTS: Nearly 40% of participants drinking 1 beer did not have a positive TAC reading. However, positive TAC readings were observed in more than 95 and in 100% of participants drinking 2 and 3 or more beers, respectively. The probability of peak TAC detection was a positive function of the number of beers consumed and a negative function of the minimum TAC threshold for detection. Drinking was somewhat more likely to be detected in females than males drinking 2 to 5 beers, but not after 1 beer. Use of AMS standard criteria only reliably detected the consumption of 5 beers, and 45.9% of all occasions of drinking 1 to 3 beers were undetected using 0.02 g/dl as a threshold. CONCLUSIONS: Peak TAC levels between 0 and 0.02 g/dl must be considered to detect the low-level drinking of 1 to 3 standard drinks, and such thresholds are necessary when researchers and clinicians want to detect low-level drinking.

Using contingency management procedures to reduce at-risk drinking in heavy drinkers.

BACKGROUND: Treatments for alcohol use disorders typically have been abstinence based, but harm reduction approaches that encourage drinkers to alter their drinking behavior to reduce the probability of alcohol-related consequences, have gained in popularity. This study used a contingency management procedure to determine its effectiveness in reducing alcohol consumption among heavy drinkers. METHODS: Eighty-two nontreatment-seeking heavy drinkers (ages 21 to 54, M = 30.20) who did not meet diagnostic criteria for alcohol dependence participated in the study. The study had 3 phases: (i) an Observation phase (4 weeks) where participants drank normally; (ii) a Contingency Management phase (12 weeks) where participants were paid $50 weekly for not exceeding low levels of alcohol consumption as measured by transdermal alcohol concentrations, <0.03 g/dl; and (iii) a Follow-up phase (12 weeks) where participants (n = 66) returned monthly for 3 months to self-report drinking after the contingencies were removed. Transdermal alcohol monitors were used to verify meeting contingency requirements; all other analyses were conducted on self-reported alcohol use. RESULTS: On average 42.3% of participants met the contingency criteria and were paid an average of $222 during the Contingency Management phase, with an average $1,998 in total compensation throughout the study. Compared to the Observation phase, the percent of any self-reported drinking days significantly decreased from 59.9 to 40.0% in the Contingency Management and 32.0% in the Follow-up phases. The percent of self-reported heavy drinking days reported also significantly decreased from 42.4% in the Observation phase to 19.7% in the Contingency Management phase, which was accompanied by a significant increase in percent days of self-reported no (from 40.1 to 60.0%) and low-level drinking (from 9.9 to 15.4%). Self-reported reductions in drinking either persisted, or became more pronounced, during the Follow-up phase. CONCLUSIONS: Contingency management was associated with a reduction in self-reported episodes of heavy drinking among nontreatment-seeking heavy drinkers. These effects persisted even after incentives were removed, indicating the potential utility of contingency management as a therapeutic intervention to reduce harmful patterns of drinking.

Effects of tryptophan depletion and a simulated alcohol binge on impulsivity.

Researchers have suggested binge drinkers experience disproportionate increases in impulsivity during the initial period of drinking, leading to a loss of control over further drinking, and that serotonergic mechanisms may underlie such effects. We examined the effects of a simulated alcohol binge and tryptophan depletion on 3 types of impulsivity-response initiation (immediate memory task [IMT]), response inhibition (GoStop task), and delay discounting (single key impulsivity paradigm [SKIP])-and tested whether observed effects were related to real-world binging. Adults (N = 179) with diverse drinking histories completed a within-subject crossover design over 4 experimental days. Each day, participants underwent 1 of 4 test conditions: tryptophan depletion/alcohol, tryptophan depletion/placebo, tryptophan-balanced control/alcohol, or tryptophan-balanced control/placebo. The simulated binge involved consuming 0.3 g/kg of alcohol at 5, 6, and 7 hr after consuming the tryptophan-depletion/balanced mixture. Impulsivity was measured before and after each drink. Relative to the placebo beverage condition, when alcohol was consumed, impulsive responding was increased at moderate and high levels of intoxication on the IMT and the GoStop but only at high levels of intoxication on the SKIP. Tryptophan depletion had no effect on impulsivity. Effects of alcohol and tryptophan manipulations on impulsivity were unrelated to patterns of binge drinking outside the laboratory. The effects of alcohol consumption on impulsivity depend on the component of impulsivity and the dose of alcohol consumed. Such effects do not appear to be a result of reduced serotonin synthesis. In addition, real-world binge drinking behaviors were unrelated to behavioral changes observed in the laboratory.

Assessing the Validity of Participant-Derived Compared to Staff-Derived Values to Compute a Binge Score.

AIMS: This study examined the validity of two methods of classifying binge drinkers. METHODS: Adult drinkers (n = 166) completed the Alcohol Use Questionnaire (AUQ) and a Timeline Followback (TLFB) interview to characterize drinking during the past 28 days. Using Townshend and Duka's (2005) recommendations, answers on three AUQ items (average drinks per hour, number of times drunk within the prior 6 months and percentage of times drunk when drinking) were used to derive a binge score that was then used to classify drinkers as Binge, Non-Binge and Unclassifiable. Two methods for calculating binge scores were compared: (a) Participant-derived, using participants' answers on the 3 AUQ items; and (b) Staff-derived, staff used TLFB interview information to answer the 3 AUQ items. Additionally, Participant- and Staff-derived classifications were used to predict future drinking behaviors assessed by a second TLFB interview. RESULTS: Participant- and Staff-derived binge scores had a low concordance rate. Staff-derived classifications were better than Participant-derived classifications at predicting future binge drinking behavior and identifying group differences in drinking behavior reported during the second TLFB interview (average drinks per hour, number of times drunk within the prior 6 months, and percentage of times drunk when drinking). CONCLUSIONS: Classifying drinkers using staff-guided TLFB interview methods instead of self-reported participant generalizations of typical drinking habits better relates to real-world drinking. Classification schemes that rely on dichotomous categorization of drinkers (Binge vs. Non-Binge) may be missing individuals who engage in harmful patterns of drinking. A continuous scale or index characterizing problematic drinking may be more useful.

Transdermal alcohol concentration data collected during a contingency management program to reduce at-risk drinking.

BACKGROUND: Recently, we demonstrated that transdermal alcohol monitors could be used in a contingency management procedure to reduce problematic drinking; the frequency of self-reported heavy/moderate drinking days decreased and days of no to low drinking increased. These effects persisted for three months after intervention. In the current report, we used the transdermal alcohol concentration (TAC) data collected prior to and during the contingency management procedure to provide a detailed characterization of objectively measured alcohol use. METHODS: Drinkers (n=80) who frequently engaged in risky drinking behaviors were recruited and participated in three study phases: a 4-week Observation phase where participants drank as usual; a 12-week Contingency Management phase where participants received $50 each week when TAC did not exceed 0.03g/dl; and a 3-month Follow-up phase where self-reported alcohol consumption was monitored. Transdermal monitors were worn during the first two phases, where each week they recived $105 for visiting the clinic and wearing the monitor. Outcomes focused on using TAC data to objectively characterize drinking and were used to classify drinking levels as either no, low, moderate, or heavy drinking as a function of weeks and day of week. RESULTS: Compared to the Observation phase, TAC data indicated that episodes of heavy drinking days during the Contingency Management phase were reduced and episodes of no drinking and low to moderate drinking increased. CONCLUSIONS: These results lend further support for linking transdermal alcohol monitoring with contingency management interventions. Collectively, studies to date indicate that interventions like these may be useful for both abstinence and moderation-based programs.

Accounting for sex-related differences in the estimation of breath alcohol concentrations using transdermal alcohol monitoring.

RATIONALE: Previously, we reported methods to estimate peak breath alcohol concentrations (BrAC) from transdermal alcohol concentrations (TAC) under conditions where alcohol consumption was controlled to produce similar BrAC levels in both sexes. OBJECTIVE: This study characterized differences in the relationship between BrAC and TAC as a function of sex and developed a model to predict peak BrAC that accounts for known sex differences in peak BrAC. METHODS: TAC and BrAC were monitored during the consumption of a varying number of beers on different days. Both men (n=11) and women (n=10) consumed one, two, three, four, and five beers at the same rate in a 2-h period. Sex and sex-related variables were considered for inclusion in a multilevel model to develop an equation to estimate peak BrAC levels from TAC. RESULTS: While peak BrAC levels were significantly higher in women than men, sex differences were not significant in observed TAC levels. This lack of correspondence was evidenced by significant sex differences in the relationship between peak TAC and peak BrAC. The best model to estimate peak BrAC accounted for sex-related differences by including peak TAC, time-to-peak TAC, and sex. This model was further validated using previously collected data. CONCLUSIONS: The relationship between peak TAC and actual peak BrAC differs between men and women, and these differences can be accounted for in a statistical model to better estimate peak BrAC. Further studies are required to extend these estimates of peak BrAC to the outpatient environment where naturalistic drinking occurs.

Use of continuous transdermal alcohol monitoring during a contingency management procedure to reduce excessive alcohol use.

BACKGROUND: Research on contingency management to treat excessive alcohol use is limited due to feasibility issues with monitoring adherence. This study examined the effectiveness of using transdermal alcohol monitoring as a continuous measure of alcohol use to implement financial contingencies to reduce heavy drinking. METHODS: Twenty-six male and female drinkers (from 21 to 39 years old) were recruited from the community. Participants were randomly assigned to one of the two treatment sequences. Sequence 1 received 4 weeks of no financial contingency (i.e., $0) drinking followed by 4 weeks each of $25 and then $50 contingency management; Sequence 2 received 4 weeks of $25 contingency management followed by 4 weeks each of no contingency (i.e., $0) and then $50 contingency management. During the $25 and $50 contingency management conditions, participants were paid each week when the Secure Continuous Remote Alcohol Monitor (SCRAM-II™) identified no heavy drinking days. RESULTS: Participants in both contingency management conditions had fewer drinking episodes and reduced frequencies of heavy drinking compared to the $0 condition. Participants randomized to Sequence 2 (receiving $25 contingency before the $0 condition) exhibited less frequent drinking and less heavy drinking in the $0 condition compared to participants from Sequence 1. CONCLUSIONS: Transdermal alcohol monitoring can be used to implement contingency management programs to reduce excessive alcohol consumption.

Decision-making heuristics and biases across the life span.

We outline a contextual and motivational model of judgment and decision-making (JDM) biases across the life span. Our model focuses on abilities and skills that correspond to deliberative, experiential, and affective decision-making processes. We review research that addresses links between JDM biases and these processes as represented by individual differences in specific abilities and skills (e.g., fluid and crystallized intelligence, executive functioning, emotion regulation, personality traits). We focus on two JDM biases-the sunk-cost fallacy (SCF) and the framing effect. We trace the developmental trajectory of each bias from preschool through middle childhood, adolescence, early adulthood, and later adulthood. We conclude that life-span developmental trajectories differ depending on the bias investigated. Existing research suggests relative stability in the framing effect across the life span and decreases in the SCF with age, including in later life. We highlight directions for future research on JDM biases across the life span, emphasizing the need for process-oriented research and research that increases our understanding of JDM biases in people's everyday lives.