A behavioral economic analysis of polydrug abuse in alcoholics: asymmetrical substitution of alcohol and cocaine

Opioid Risk Tool, in-hospital opioid exposure, and opioid demand predict pain outcomes following traumatic injury

Prescribed opioids are a mainstay pain treatment after traumatic injury, but a subgroup of patients may be at risk for continued opioid use. We evaluated the predictive utility of a traditional screening tool, the Opioid Risk Tool (ORT), and two other measures: average in-hospital milligram morphine equivalents (MME) per day and an assessment of opioid demand in predicting pain outcomes. Assessments of pain-related outcomes (pain intensity, interference, injury-related stress, and need for additional pain treatment) were administered at 2 weeks and 12 months post-discharge in a sample of 34 patients hospitalized for traumatic injury. Bayesian linear models were used to evaluate changes in responses over time as a function of predictors. High-risk ORT, higher MME per day, and greater opioid demand predicted less change in outcomes over time. This report provides first evidence that malleable factors of opioid and opioid demand have utility in predicting pain outcomes following traumatic injury.

Patterns of polysubstance use among adults in Malaysia-A latent class analysis

INTRODUCTION

Polysubstance use is the use of more than one non-prescribed licit or illicit substance at one time. This is a common phenomenon, but little is known about the severity and the various substances used by adults in Malaysia.

OBJECTIVE

To determine the pattern of polysubstance use and its associated factors among general adults in Malaysia.

METHODOLOGY

This was a secondary data analysis from the National Health and Morbidity Survey (NHMS) 2019), a cross-sectional population survey with a two-stage stratified random sampling design. A total of 10,472 Malaysians aged 18 years and above participated in this survey. Polysubstance use was defined as concurrent use of more than one substance, either alcohol, tobacco, or drugs (opioids, marijuana, amphetamine/ methamphetamine or kratom). A latent class analysis (LCA) was used to identify the membership of polysubstance groups. The association of class membership with demographic profiles was examined using Multinomial Logistic Regression analysis.

RESULTS

Fit indices (AIC = 16458.9, BIC = 16443.6) from LCA supported 3 classes solution: Class 1; "moderate-drug" group primarily combination used of tobacco and alcohol (2.4%), Class 2; "high-drug" group using multiple substance including kratom (0.3%) and Class 3; "low-drug" group reporting minimal alcohol and tobacco use or non-user (97.3%). The multinomial model showed young adults (18-40 years) had a higher likelihood of being polysubstance users both for moderate-drug class (OR = 4.1) and high-drug class (OR = 3.9) compared to older age (≥60 years). Chinese (OR = 18.9), Indian (OR = 23.3), Indigenous Sabah & Sarawak (OR = 34.6) and others ethnicity (OR = 8.9) showed higher odds of being moderate-drug users than Malays. The greater odds of moderate-drug use for males (OR = 35.5), working groups (OR = 1.5) and low education level group (OR = 3.2).

CONCLUSION

Our study highlights patterns and demographics related to the use of polysubstances among adults in Malaysia. These results would help formulate specific prevention programmes for these high-risk groups.

A systems framework depicting how complex neighborhood dynamics and contextual factors could impact the effectiveness of an alcohol outlet zoning policy

An updated zoning policy eliminating all alcohol outlets (liquor stores) in residential districts was implemented to reduce high rates of violent crime in Baltimore City. Diverse stakeholders were engaged in group model building (GMB) activities to develop causal loop diagrams (CLDs) that elucidate the impact of the new zoning policy on crime, and more broadly, the potentially unintended social and environmental consequences of the policy. Three distinct groups, community advocates, city officials/academics, and community residents, participated in three separate GMB sessions. Three CLDs, one from each stakeholder group, were created to depict the possible outcomes of the zoning policy. Our findings offer insight into potential unintended consequences of removing liquor stores from residential areas that may undermine the policy. Community members described the need for additional supports related to mental health and substance use, opportunities for investment in the community, access to other goods and services, and community-police relations to ensure the policy achieved its intended goal of reducing violent crime. Our findings highlight the importance of timely engagement of local stakeholders to understand how complex neighborhood dynamics and contextual factors could impact the effectiveness of a zoning policy change.

Additive roles of tobacco and cannabis co-use in relation to delay discounting in a sample of heavy drinkers

RATIONALE

Alcohol use disorder (AUD) is associated with steeper delay discounting rates; however, it is unknown whether substance co-use, particularly cannabis use, has an additive effect on discounting rates among heavy drinkers. Furthermore, it is unclear whether substance co-use and delay discounting are independently associated with AUD severity.

OBJECTIVES

The purpose of this study was to determine whether alcohol, tobacco, and cannabis co-use impacts delay discounting rates. We also sought to determine whether substance co-use and delay discounting were associated with AUD symptom counts.

METHODS

The study sample was culled from several human laboratory studies and consisted of 483 heavy drinking individuals who completed a baseline visit (prior to experimental procedures). Participants were divided into groups based on self-reported alcohol, tobacco, and cannabis use during the past 30 days: alcohol only (n = 184), alcohol + cigarettes (n = 89), alcohol + cannabis (n = 82), and tri-use (n = 128). We examined discounting rates across the 4 groups and used multiple linear regression to test whether co-use and delay discounting were associated with AUD symptoms.

RESULTS

After adjusting for covariates, individuals in the alcohol + cannabis group and the tri-use group had steeper discounting rates relative to the alcohol-only group. In addition, tri-use and delay discounting rates were independently correlated with a greater number of AUD symptoms.

CONCLUSIONS

Delay discounting rates were significantly greater among subgroups reporting cannabis use providing partial support for an additive effect, while also highlighting the importance of co-use substance type. Both tri-use and delay discounting were associated with greater AUD severity, which may provide relevant intervention targets.

Decreased cocaine demand following contingency management treatment

A hypothetical cocaine purchasing task (CocPT) was used to assess changes in cocaine demand in the context of contingency management (CM) treatment for cocaine use disorder (CUD). Participants (N = 89) were treatment-seeking individuals with CUD receiving 4 weeks of abstinence-based, high-magnitude CM. Treatment response (vs. non-response) was operationally defined as the submission of 6 consecutive cocaine-negative urine samples across two weeks. The CPT was assessed at baseline, week 2, and week 5. Demand data were well described by the exponentiated demand model, and baseline demand indices (Q0, Pmax, breakpoint, essential value) were significantly associated with self-report measures of cocaine use. The probability of being a zero-responder reporting zero cocaine consumption at all prices significantly increased over the course of treatment, and was greater among treatment responders vs. non-responders. Among non-zero demand data, decreases in Omax, Pmax, breakpoint, and essential value were observed over the course of CM treatment, favoring responders. To our knowledge, this is the first study to assess change in cocaine demand in the context of CM treatment targeting cocaine abstinence. Our results support the utility of cocaine demand as a measure for both identifying individuals with greater treatment need and tracking relapse risk over the course of treatment.

Assessment of demand for methamphetamine and cigarettes among individuals with methamphetamine use disorder

Methamphetamine (MA) is a highly addictive stimulant with recent upward trends in prevalence and associated public health problems. Drug demand, as assessed by hypothetical purchasing tasks, has been useful in addictions research and may help our understanding of the factors influencing MA use. However, no studies have assessed MA demand using current models of demand. The purpose of the current study was to assess demand for MA using a hypothetical drug purchasing task. Given high rates of cigarette smoking among MA users, it was of interest also to assess and compare demand for MA relative to cigarettes. Participants consisted of non-treatment-seeking volunteers with MA use disorder (N = 18), of whom 17 reported daily smoking. Results showed the exponentiated demand model provided a good fit to consumption data. Results from Bayesian generalized linear modeling demonstrated multiple positive relationships (posterior probability ≥75%) between self-reported drug use (days MA used in the past 30 days, cigarettes smoked per day) and indices of demand for each drug (Qo, Omax, Pmax, and break point). Comparing MA to cigarettes, results from Bayesian generalized linear mixed modeling revealed greater abuse liability for MA compared to cigarettes (posterior probability ≥99%) based on α and essential value. Overall, the findings of the current study support the feasibility and validity of the exponentiated demand model for assessing demand for drugs among individuals with MA use disorder. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Initial development of a brief assessment of cocaine demand

Cocaine demand is a behavioral economic measure assessing drug reward value and motivation to use drug. The purpose of the current study was to develop a brief assessment of cocaine demand (BACD). Results from the BACD were compared with self-report measures of cocaine use. Participants consisted of treatment-seeking individuals with cocaine use disorder (N = 22). Results revealed that indices of brief demand were significantly associated with various self-report measures of cocaine use. Overall, these results support the utility of a BACD for assessing cocaine demand.

Purchase task sensitivity to drug and nondrug reinforcers in opioid-agonist treatment patients

The behavioral economics of substance abuse has been increasingly recognized as a method of determining the value of abused substances for individuals who use those substances. It has been hypothesized that such analyses could serve as a clinical tool and that demand functions can be targeted predictors for the level of intervention necessary. This study evaluated the sensitivity of a demand task in 2 patient groups in a medication assisted treatment program (methadone maintenance), those who had used opioids in the last 2 months and those who had not used opioids in at least 18 months. Demand for 7 drugs and a control was assessed using hypothetical purchase tasks. Participants maintaining long-term abstinence had significantly higher α (sensitivity to price) and lower Q₀ (intensity of demand) for heroin than participants who had recently used opioids. Further research is necessary to illustrate if treatment is responsible for this reduction in demand. If so, demand analyses may provide clinical utility as an aid for treatment planning or as a target for treatment.

Drug addiction co-morbidity with alcohol: Neurobiological insights

Addiction is a chronic disorder that consists of a three-stage cycle of binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. These stages involve, respectively, neuroadaptations in brain circuits involved in incentive salience and habit formation, stress surfeit and reward deficit, and executive function. Much research on addiction focuses on the neurobiology underlying single drug use. However, alcohol use disorder (AUD) can be co-morbid with substance use disorder (SUD), called dual dependence. The limited epidemiological data on dual dependence indicates that there is a large population of individuals suffering from addiction who are dependent on more than one drug and/or alcohol, yet dual dependence remains understudied in addiction research. Here, we review neurobiological data on neurotransmitter and neuropeptide systems that are known to contribute to addiction pathology and how the involvement of these systems is consistent or divergent across drug classes. In particular, we highlight the dopamine, opioid, corticotropin-releasing factor, norepinephrine, hypocretin/orexin, glucocorticoid, neuroimmune signaling, endocannabinoid, glutamate, and GABA systems. We also discuss the limited research on these systems in dual dependence. Collectively, these studies demonstrate that the use of multiple drugs can produce neuroadaptations that are distinct from single drug use. Further investigation into the neurobiology of dual dependence is necessary to develop effective treatments for addiction to multiple drugs.

Why Switch? - Motivations for Self-Substitution of Illegal Drugs

Self-substitution is the conscious switch from one drug to another for reasons such as price, availability, desired effect, or perceived benefit of the substitute drug. Purpose/Objectives: This study aimed to describe drug use patterns and motivations associated with substitution. We examined correlates of lifetime substitution among individuals with substance use disorder. Methods: A cross-sectional study of 771 treatment-enrolled individuals. We used self-report for determining the lifetime prevalence, correlates, and motivations for substitution. Results: Of the 771 respondents, 570 (73.9%) reported ever substituting their preferred substance. The main incentives for substitution were availability (23.7%) and curiosity (20.2%). Among heroin or cannabis preferers, improved effects or less adverse effects of the substitute drug, self-medication, and managing withdrawal symptoms were significant substitution incentives. Increased odds for substitution were observed for past 12 months use of cannabis (OR = 1.51, CI = 1.06-4.52), prescription opioids (OR = 2.86, CI = 1.81-4.52), novel psychoactive substances (OR = 2.68, CI = 1.64-4.36), and repeated admission (OR = 1.50, CI = 1.05-2.14). Older age at onset-of-use was negatively associated with substitution (OR = 0.95, CI = 0.93-0.98). Conclusions: Self-substitution of one substance for another is a highly prevalent behavior among treatment-enrolled patients with substance use disorder. Clinicians caring for substance use disorder patients should be aware of substitution patterns involving the use of highly potent substances, which constitutes a risk to patients. Results underscore the benefit of substitution patterns analyses, as they reveal important information on the characteristics of persons who use drugs and their motivations.

Substitute Addictions in Persons with Substance Use Disorders: A Scoping Review

Substitute addictions, addictive behaviors that sequentially replace each other's functions, have implications for recovery trajectories but remain poorly understood. We sought to scope the extent, range, and characteristics of research on substitute addictions in persons with substance use disorders. Method: Using Arksey and O'Malley's framework for scoping reviews, a systematic search was conducted to identify publications that referenced substitute addictions up to April 2018. Study characteristics were extracted and summarized to provide an overview of the extant literature. Results: The 63 included studies show that substitute addictions are terminologically and conceptually ambiguous. Much of the available literature is concentrated in developed contexts - and in particular the United States of America. While presentations varied, at least two sub-types of substitute addictions appeared: long-term replacement and temporary replacement. Existing theories suggest a multifactorial etiology. Conclusions: The findings suggest a strong need for: increased awareness of substitute addictions and its potential consequences for recovery; interventions that structure prevention and pre-, during-, and post-treatment interactions as well as future research to explore its nature and dynamics drawing on multiple methods.

The switch from one substance-of-abuse to another: illicit drug substitution behaviors in a sample of high-risk drug users

Background

Substitution can be defined as the consciously motivated choice to use one drug, either licit or illicit, instead of another, due to perceptions of cost, availability, safety, legality, substance characteristics, and substance attributions. Substitution represents a potential risk to drug users, mainly when substitutes are of higher potency and toxicity. This study offers a basic conceptualization of illicit substitution behavior and describes substitution patterns among users of two highly prevalent drugs of abuse-heroin and cannabis.

Methods

Here, 592 high-risk drug users undergoing pharmacological and psycho-social treatment were interviewed. Patients were asked questions about current drug use, lifetime substitution, and substitution patterns. Descriptive statistics, chi-square tests of independence, and multinomial logistic regressions were used to identify and test correlates of substitution patterns for heroin and cannabis.

Results

Of the 592 drug users interviewed, 448 subjects (75.7%) reported having substituted their preferred drug for another illicit substance. Interviews yielded a total of 275 substitution events reported by users of cannabis, and 351 substitution events reported by users of heroin. The most frequently reported substitution substances for responders who preferred heroin were illicit non-prescribed "street" methadone (35.9%), followed by oral and transdermal prescription opioids (17.7%). For responders who preferred cannabis, substitution for synthetic cannabinoid receptor agonists (33.5%) followed by alcohol (16.0%) were the most commonly reported. Age at onset-of-use (p < 0.005), population group (p = 0.008), and attending treatment for the first time (p = 0.026) were significantly associated with reported lifetime substitution. Past-year use of stimulants, heroin, hallucinogens, methylenedioxymethamphetamine (MDMA), and novel psychoactive substances were-at the 95% confidence level-also significantly associated with reported lifetime substitution. In multivariate analysis, the odds for methadone substitution among heroin users were significantly affected by age at onset-of-use, type of treatment center, and education. Odds for substitution for synthetic cannabinoid receptor agonists among cannabis users were significantly affected by age, population group, type of treatment center, and education.

Conclusion

Self-substitution behavior should be considered by clinicians and policymakers as a common practice among most drugusers. Substitution for street methadone provides evidence for the ongoing diversion of this substance from Opioid Maintenance Treatment Centers, while the prominence of substitution of synthetic cannabinoids among dual-diagnosis patients should be regarded as an ongoing risk to patients that needs to be addressed by clinicians. Analysis of additional substitution patterns should provide further valuable insights into the behavior of drugusers.

Examining the Utility of a General Substance Use Spectrum Using Latent Trait Modeling

BACKGROUND

Polysubstance use (PSU; lifetime use of multiple substances) is common among individuals with problematic alcohol/substance use and is associated with poor prognosis and poor physical/mental health. Furthermore, simultaneous co-use of substances, such that drug effects overlap, is also common and related to unique risks (e.g. overdose). Despite the importance of PSU, current diagnostic systems continue to conceptualize problems with alcohol/substances as class-specific constructs (e.g. Stimulant Use Disorder), which essentially ignore many unique PSU processes.

METHODS

The current study modeled problems with alcohol, cannabis, stimulants, sedatives, opiates, and simultaneous co-use of these substances as a manifestation of a general substance use continuum versus as correlated class-specific constructs in a sample of young-adults(n = 2482) using confirmatory factor analysis. Utility of the models was evaluated by examining associations between the general substance use spectrum and class-specific latent factors with measures of anxiety, ADHD, adult antisocial problems, borderline symptoms, neuroticism, and intelligence in a subset of the sample(n=847).

RESULTS

Findings supported the conceptualization of problems with all substances, including co-use of substances, as being manifestations of a general substance use spectrum, as class-specific constructs were not differentially associated with other measures of psychological dysfunction. Examination of this general substance use spectrum indicated that all substances, separately and co-use, were robustly informative of this spectrum, but tended to discriminate between different severity levels.

DISCUSSION

The general substance use spectrum allows for integration of information from the use and co-use of all substances to provide better assessment of overall problems with substances compared to class-specific constructs.

One Is Not Enough: Understanding and Modeling Polysubstance Use

Substance use disorder (SUD) is a chronic, relapsing disease with a highly multifaceted pathology that includes (but is not limited to) sensitivity to drug-associated cues, negative affect, and motivation to maintain drug consumption. SUDs are highly prevalent, with 35 million people meeting criteria for SUD. While drug use and addiction are highly studied, most investigations of SUDs examine drug use in isolation, rather than in the more prevalent context of comorbid substance histories. Indeed, 11.3% of individuals diagnosed with a SUD have concurrent alcohol and illicit drug use disorders. Furthermore, having a SUD with one substance increases susceptibility to developing dependence on additional substances. For example, the increased risk of developing heroin dependence is twofold for alcohol misusers, threefold for cannabis users, 15-fold for cocaine users, and 40-fold for prescription misusers. Given the prevalence and risk associated with polysubstance use and current public health crises, examining these disorders through the lens of co-use is essential for translatability and improved treatment efficacy. The escalating economic and social costs and continued rise in drug use has spurred interest in developing preclinical models that effectively model this phenomenon. Here, we review the current state of the field in understanding the behavioral and neural circuitry in the context of co-use with common pairings of alcohol, nicotine, cannabis, and other addictive substances. Moreover, we outline key considerations when developing polysubstance models, including challenges to developing preclinical models to provide insights and improve treatment outcomes.

Inclusion of Cannabis Users in Alcohol Research Samples: Screening In, Screening Out, and Implications

BACKGROUND

Alcohol and cannabis are frequently co-used, as 20-50% of those who drink alcohol report co-using cannabis. This study is based on the argument that alcohol researchers should enroll cannabis users in human laboratory studies of alcohol use disorder (AUD) to strengthen generalizability. This study examines how heavy drinking cannabis users differ from non-cannabis using heavy drinkers.

METHODS

In a community sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users were identified through: (a) self-reported cannabis use in the past 6 months and (b) positive urine toxicology test for tetrahydrocannabinol (THC). Cannabis users, identified as described previously, were compared with non-cannabis users on demographic and clinical characteristics.

RESULTS

Those who endorsed cannabis use in the past 6 months reported more binge drinking days. Participants who tested positive for THC had higher Alcohol Use Disorder Identification Test scores and more binge drinking days. Younger age and being a tobacco smoker were associated with an increased likelihood of cannabis use in the past 6 months, whereas male gender and being a tobacco use were associated with a greater likelihood of testing positive for THC. Individuals with cannabis use disorder (CUD) endorsed more depression and anxiety and had higher AUD symptom counts than cannabis users without CUD.

CONCLUSIONS

The inclusion of cannabis users in AUD samples allows for increased clinical severity. Excluding cannabis users from AUD studies may limit representativeness and expend unnecessary study resources. Lastly, tobacco use may explain a large portion of the effects of cannabis use on sample characteristics.

SHORT SUMMARY

Alcohol and cannabis are frequently co-used substances. In a sample of non-treatment-seeking heavy drinkers (n = 551, 35% female), cannabis users reported higher alcohol use and higher likelihood of tobacco use than non-cannabis users. Including cannabis users in alcohol research studies will improve representativeness and likely increase clinical severity.

Addiction is driven by excessive goal-directed drug choice under negative affect: translational critique of habit and compulsion theory

Drug addiction may be a goal-directed choice driven by excessive drug value in negative affective states, a habit driven by strong stimulus-response associations, or a compulsion driven by insensitivity to costs imposed on drug seeking. Laboratory animal and human evidence for these three theories is evaluated. Excessive goal theory is supported by dependence severity being associated with greater drug choice/economic demand. Drug choice is demonstrably goal-directed (driven by the expected value of the drug) and can be augmented by stress/negative mood induction and withdrawal-effects amplified in those with psychiatric symptoms and drug use coping motives. Furthermore, psychiatric symptoms confer risk of dependence, and coping motives mediate this risk. Habit theory of addiction has weaker support. Habitual behaviour seen in drug-exposed animals often does not occur in complex decision scenarios, or where responding is rewarded, so habit is unlikely to explain most human addictive behaviour where these conditions apply. Furthermore, most human studies have not found greater propensity to habitual behaviour in drug users or as a function of dependence severity, and the minority that have can be explained by task disengagement producing impaired explicit contingency knowledge. Compulsion theory of addiction also has weak support. The persistence of punished drug seeking in animals is better explained by greater drug value (evinced by the association with economic demand) than by insensitivity to costs. Furthermore, human studies have provided weak evidence that propensity to discount cost imposed on drug seeking is associated with dependence severity. These data suggest that human addiction is primarily driven by excessive goal-directed drug choice under negative affect, and less by habit or compulsion. Addiction is pathological because negative states powerfully increase expected drug value acutely outweighing abstinence goals.

Choice is relative: Reinforcing value of food and activity in obesity treatment

Persons with obesity find high-energy-dense food and sedentary behaviors highly reinforcing. Diets and exercise programs deprive individuals of many favorite foods and activities, which can counterproductively heighten their value and lead to relapse. Since the value of reinforcers depend on the alternatives available, one approach to reducing food and sedentary activity reinforcement is to build healthy alternative reinforcers. Current behavioral treatment programs for children and adults do not attempt to build alternative reinforcers as substitutes for unhealthy behaviors to reduce the impact of food or activity deprivation on the motivation to eat or be inactive. A goal of the next generation of obesity treatment programs should focus on development of healthy behaviors as reinforcers so that people will be motivated to engage in them. This article provides an overview of relationships among reinforcers, how understanding substitutes and complements can influence eating and activity, and how enriching a person's environment and providing choice architecture can enhance weight control. Ideas for translation of these basic behavioral economic principles to obesity treatment programs are discussed. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Patterns of polysubstance use and simultaneous co-use in high risk young adults

BACKGROUND

Polysubstance use (PSU) is associated with worse prognosis and poorer physical and mental health compared to single substance use. The current study provides information about PSU patterns by examining a diverse range of alcohol/substance use behaviors ranging from low-level experimentation to indicators of severe abuse. In addition, the current study, for the first time, examines how simultaneous co-use of multiple substances cluster with other more commonly studied PSU behaviors.

METHODS

Latent Class Analysis was used to identify patterns of substance use, in a sample of young-adults (n = 2098), using 25 items from the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA-II) including: items assessing severity of problems with alcohol, cannabis, stimulants, opiates, and sedatives; items assessing # of lifetime uses; items assessing simultaneous co-use of all combinations of substances. Then the association of class membership and age, antisocial and impulsive personality, experience seeking, anxiety, and neuroticism was examined using Multinomial Regression.

RESULTS

Fit indices (i.e. AIC, SSABIC, and entropy) and interpretability of classes supported a five-class solution: "Low Problems" (32% of sample), "Alcohol Primary" (11%), "Alcohol and Cannabis" (25%), "Moderate PSU" (23%), and "Severe PSU" (9%). Simultaneous co-use behaviors discriminated between lower and higher severity groups. Externalizing personality constructs robustly predicted membership in the "Moderate" and "Severe" PSU classes compared to the "Alcohol Primary" class.

CONCLUSIONS

PSU patterns followed an additive pattern of use with lower severity classes using alcohol/cannabis and more severe classes using other illicit substances in addition. Co-use items provided valuable information about PSU severity.

A concurrent pictorial drug choice task marks multiple risk factors in treatment-engaged smokers and drinkers

Concurrent choice tasks, where participants choose between a drug versus natural reward, predict dependence vulnerability in animals and humans. However, the sensitivity of concurrent choice tasks to multiple risk factors in treatment-engaged drug users has not been comprehensively tested. In experiment 1, 33 recently hospitalized smokers who were engaged with the smoking cessation service made forced choices between enlarging pictures of people smoking versus not smoking. In experiment 2, 48 drinkers who were engaged in an outpatient alcohol treatment service made forced choices between enlarging pictures of alcohol versus food. In these experiments, percent drug picture choice was significantly associated with dependence severity, craving, self-reported reasons for drug use (negative coping and cued craving), depression, anxiety, withdrawal intolerance, drug use frequency prior to treatment, and current abstinence status (coefficients ranged from r=0.39 to 0.66). The concurrent pictorial drug choice task is sensitive to multiple risk factors in clinical, treatment-engaged drug users, and may be used to identify individuals requiring more support, to test experimental treatment manipulations, and to translate to animal concurrent self-administration procedures.

Baseline cocaine demand predicts contingency management treatment outcomes for cocaine-use disorder

Cocaine use disorder (CUD) is a significant public health issue. Behavioral interventions such as contingency management (CM) have been demonstrated to be highly effective in promoting cocaine abstinence. However, identifying individual characteristics associated with cocaine relapse may help improve treatment outcomes. Cocaine demand is a behavioral economic measure that shares a scientific foundation with CM. In the current study, we assessed baseline cocaine demand using a hypothetical cocaine purchasing task. Participants (N = 58) consisted of treatment-seeking individuals with CUD. All participants received 1 month of CM treatment for cocaine abstinence, and treatment responders were defined as presenting 6 consecutive cocaine negative urine samples from thrice weekly clinic visits. Demand data were well described by the exponentiated demand model. Indices of demand (intensity of demand [Q₀], elasticity [α]) were significantly associated with recent (last 30 days) cocaine use. Importantly, linear regression revealed that CM treatment nonresponders presented significantly higher Q₀ (p = .025). Subsequent quantile regression analyses examining the relationship between CM treatment response and Q₀ revealed statistically reliable effects of being a nonresponder across 3 of the lower percentiles (i.e., 15, 25, and 30). Overall, these findings provide further support for the utility of exponentiated demand model. To our knowledge, this is the first study to demonstrate an association between baseline demand and contingency management response and systematically extend the findings of prior demand research to a novel drug class, cocaine. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Quantity versus quality: Convergent findings in effort-based choice tasks

Organisms must frequently make cost-benefit decisions based on time, risk, and effort in choosing rewards to pursue. Various tasks have been developed to assess effort-based choice in rats, and experimenters have found largely similar results across tasks and brain regions. In this review, we focus primarily on the convergence of different effort-based choice tasks where quality or quantity of reward are manipulated. In the former, the rat is typically presented with the option to work for a preferred reward or select a less preferred, but freely-available reward. In such paradigms, the rewards are of different identities but are confirmed to differ qualitatively in value by a food preference task when both are freely-available. In the latter task type, rats are required to select between higher magnitude versus lower magnitudes of the same reward, but each with a similar effort requirement. We discuss the strengths/limitations of these paradigms, and describe brain regions that have been probed that result in converging or equivocal findings. Results are also reviewed with reference to a need for future work, and the broader impacts and implications of studies probing the mechanisms of effort.

The experimental tobacco marketplace: Narrative influence on electronic cigarette substitution

Despite promising decreases in overall smoking rates, a significant proportion of the population continues to engage in this costly behavior. Substituting e-cigarettes for conventional cigarettes is an increasingly popular harm-reduction strategy. Narratives may be one method of increasing the substitutability of e-cigarettes. Participants (N = 160) were assigned to 1 of 4 narratives that described a close friend becoming ill. In the positive narrative, participants read about a friend that became ill but learned it was only the flu. In the negative narrative, the friend became ill from smoking cigarettes; in the negativeregret narrative, the friend became ill from smoking cigarettes and explicitly expressed regret for having started smoking; and in the negativechange narrative, the friend became ill from smoking, switched to e-cigarettes, and made a full recovery. Participants then completed an experimental tobacco marketplace (ETM) in which they could purchase conventional cigarettes and alternative nicotine products, including e-cigarettes. Across ETM trials, the price of conventional cigarettes increased while the price of the alternative products remained constant. Initial purchasing of conventional cigarettes decreased and initial purchasing of e-cigarettes increased in the negative-change group compared with the other three groups. This finding was moderated by conventional cigarette dependence and perception of e-cigarette risk but not previous e-cigarette exposure. Narratives can change conventional cigarette and e-cigarette purchasing in an ETM that mimics real-world marketplaces. Narratives can be a valuable harm-reduction tool because they are cost-effective, can be widely disseminated, and can be personalized to individuals. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Sex differences in the prevalence and correlates of emergency department utilization among adults with prescription opioid use disorder

BACKGROUND

The emergency department (ED) is well-suited as an opportunity to increase treatment access for prescription opioid use disorder (POUD). We examined sex differences in ED utilization among individuals with POUD to understand potential sex-specific treatment barriers and needs.

METHODS

Data from the 2005-2014 National Surveys on Drug use and Health were analyzed to examine the prevalence and correlates of past-year ED utilization among male and female adults aged 18 or older with POUD (n = 4412).

RESULTS

Overall, 58.2% of adults with POUD reported past-year ED utilization. Adjusted logistic regression revealed that females (vs. males) with POUD were more likely to report past-year ED utilization. Among females with POUD, older age, lower income, obtaining opioids from a physician, major depressive episode, and greater POUD severity were associated with increased odds of ED utilization. Among males with POUD, public insurance and obtaining opioids from a physician were associated with ED utilization. A larger proportion of males with POUD reporting ED use had multiple substance use disorders than those with no ED use. Treatment history (lifetime or past-year) for alcohol, drugs, or opioid use was associated with increased odds of ED use among males and females with POUD. Conclusions/Importance: Males and females with POUD presenting to the ED may have distinct predisposing, enabling, and need-related correlates. Sex-specific screening and intervention strategies may be useful to maximize the utility of the ED to address POUD.

Persistent effect of withdrawal from intravenous methamphetamine self-administration on brain activation and behavioral economic indices involving an effort cost

Exposure to drugs of abuse produces maladaptive changes in cost-benefit decision-making, including the evaluation of time and risk. Studies probing the effects of drug exposure on such evaluations have primarily used experimenter-administered drug regimens. Similarly, while much is known about the neural bases of effort, there have been relatively fewer investigations of the effects of drug experience on effort-based choices. We recently reported that experimenter-administered methamphetamine (meth) resulted in steeper discounting of effort for food rewards in rats, when assessed in protracted withdrawal. Here, we studied rats that underwent withdrawal from weeks of meth intravenous self-administration that later could freely select between a high effort, preferred option (progressive ratio lever pressing for sucrose pellets) versus a low effort, less preferred option (freely-available lab chow). We found decreased effort for the preferred reward and changes in a behavioral economic index demonstrating an increased sensitivity to effort in meth-experienced rats. Critically, the decreased effort for the preferred option was only present in the context of a competing option, not when it was the only option. We also confirmed rats preferred sucrose pellets over chow when both were freely available. These long-lasting changes were accompanied by decreased c-Fos activation in ventral striatum and basolateral amygdala, regions known to be important in effort-based choices. Taken together with our previous observations, these results suggest a robust and enduring effect of meth on value-based decision-making, and point to the underlying neural mechanisms that support the evaluation of an effort cost.

Assessing the longitudinal stability of latent classes of substance use among gay, bisexual, and other men who have sex with men

BACKGROUND

Association between substance use and HIV-risk among gay and bisexual men (GBM) is well documented. However, their substance use patterns are diverse, and it is unknown whether self-reported use patterns are stable over time.

METHODS

Sexually-active GBM, aged >16 years, were recruited in Metro Vancouver using respondent-driven sampling and followed across 5 study visits at six-month intervals (n = 449). To identify distinct patterns of substance use and their longitudinal stability, Latent Transition Analysis (LTA) was conducted for drugs reported by at least 30 participants. Intraclass correlation coefficients (ICC) quantified the stability of class assignments.

RESULTS

Six classes characterizing 'limited drug use' (i.e., low use of all drugs, except alcohol), 'conventional drug use' (i.e., use of alcohol, marijuana, and tobacco), 'club drug use' (i.e., use of alcohol, cocaine, and psychedelics), 'sex drug use' (i.e., use of alcohol, crystal meth, GHB, poppers, and erectile dysfunction drugs), 'street drug use' (i.e., use of alcohol and street opioids) and 'assorted drug use' (i.e., use of most drugs) were identified. Across five visits (2.5 years), 26.3% (n = 118/449) of GBM transitioned between classes. The prevalence of limited use trended upwards (Baseline:24.5%, Visit 5:28.3%, p < 0.0001) and assorted use trended downwards (13.4%-9.6%, p = 0.001). All classes had strong longitudinal stability (ICC > 0.97).

CONCLUSION

The stability of latent substance use patterns highlight the utility of these measures in identifying patterns of substance use among people who use drugs - potentially allowing for better assessment of these groups and interventions related to their health.

Prevalence, patterns, and correlates of multiple substance use disorders among adult primary care patients

BACKGROUND

Addressing multiple substance use disorders (SUDs) in primary care-based screening and intervention may improve SUD treatment access, engagement, and outcomes. To inform such efforts, research is needed on the prevalence and patterns of multiple SUDs among primary care patients.

METHODS

Data were analyzed from a sample of 2000 adult (aged ≥ 18) primary care patients recruited for a multisite National Drug Abuse Treatment Clinical Trials Network (CTN) study (CTN-0059). Past-year DSM-5 SUDs (tobacco, alcohol, and drug) were assessed by the modified Composite International Diagnostic Interview. Prevalence and correlates of multiple versus single SUDs were examined. Latent class analysis (LCA) was used to explore patterns of multiple SUDs.

RESULTS

Multiple SUDs were found among the majority of participants with SUD for alcohol, cannabis, prescription opioids, cocaine, and heroin. Participants who were male, ages 26-34, less educated, and unemployed had increased odds of multiple SUDs compared to one SUD. Having multiple SUDs was associated with greater severity of tobacco or alcohol use disorder. LCA of the sample identified three classes: class 1 (83.7%) exhibited low prevalence of all SUDs; class 2 (12.0%) had high-moderate prevalence of SUDs for tobacco, alcohol, and cannabis; class 3 (4.3%) showed high prevalence of SUD for tobacco, opioids, and cocaine. LCA-defined classes were distinguished by sex, age, race, education, and employment status.

CONCLUSIONS

Findings suggest that primary care physicians should be aware of multiple SUDs when planning treatment, especially among adults who are male, younger, less educated, or unemployed. Interventions that target multiple SUDs warrant future investigation.

Severity and outcomes of acute alcoholic pancreatitis in cannabis users

BACKGROUND

Cannabis is the most commonly and widely used illicit drug in the world and is also the most commonly used drug of abuse in alcohol drinkers. Experimental studies have shown conflicting results of the effects of cannabis on the severity of acute pancreatitis (AP). The purpose of this study is to ascertain the clinical effects of simultaneous alcohol and cannabis use on severity at presentation and outcomes of acute alcoholic pancreatitis (AAP).

METHODS

A retrospective review was conducted on the patients discharged with principle or secondary diagnosis of AP using ICD-9 & ICD-10 codes during the time period from January 2006 to December 2015 at a large community-based hospital in Central Georgia. Patients with alcoholic pancreatitis with cannabis (CB+) and without cannabis (CB-) use were identified and were matched with sex and age.

RESULTS

Our study findings showed that a greater percentage of CB+ patients did not have a systemic inflammatory response syndrome (SIRS) score (P=0.043), had a lower BISAP score (P=0.031), and had a significantly lower BUN level (P=0.033), but there was no difference in the Balthazar Index and revised Atlanta classification severity between the two groups. CB+ patients tended to need less ICU care than CB- patients (P=0.059).

CONCLUSIONS

Based on our findings, we found that CB+ patients had less severe presentation of AAP indicating that cannabis could modulate the inflammatory effect of alcohol on the pancreas. Further large scale prospective studies are needed to confirm our results.

Inhibiting subthalamic nucleus decreases cocaine demand and relapse: therapeutic potential

Preclinical evidence indicates that inactivation of subthalamic nucleus (STN) may be effective for treating cocaine addiction, and therapies that target STN, e.g. deep brain stimulation, are available indicating that this may have clinical promise. Here, we assessed the therapeutic potential of STN inactivation using a translationally relevant economic approach that quantitatively describes drug-taking behavior, and tested these results with drug-seeking tasks. Economic demand for cocaine was assessed in rats (n = 11) using a within-session threshold procedure in which cocaine price (responses/mg cocaine) was sequentially increased throughout the session. Cocaine demand was assessed in this manner immediately after bilateral microinfusions into STN of either vehicle (artificial cerebrospinal fluid) or the GABAA receptor agonist muscimol. A separate group of animals (n = 8) was tested for changes in cocaine seeking either during extinction or in response to cocaine-associated cues. Muscimol-induced inhibition of STN significantly attenuated cocaine consumption at high prices, drug seeking during extinction and cued reinstatement of cocaine seeking. In contrast, STN inhibition did not reduce cocaine consumption at low prices or locomotor activity. Thus, STN inactivation reduced economic demand for cocaine and multiple measures of drug seeking during extinction. In view of the association between economic demand and addiction severity in both rat and human, these results indicate that STN inactivation has substantial clinical potential for treatment of cocaine addiction.

Oxytocin Acts in Nucleus Accumbens to Attenuate Methamphetamine Seeking and Demand

BACKGROUND

Evidence indicates that oxytocin, an endogenous peptide well known for its role in social behaviors, childbirth, and lactation, is a promising addiction pharmacotherapy. We employed a within-session behavioral-economic (BE) procedure in rats to examine oxytocin as a pharmacotherapy for methamphetamine (meth) addiction. The BE paradigm was modeled after BE procedures used to assess motivation for drugs in humans with addiction. The same BE variables assessed across species have been shown to predict later relapse behavior. Thus, the translational potential of preclinical BE studies is particularly strong.

METHODS

We tested the effects of systemic and microinfused oxytocin on demand for self-administered intravenous meth and reinstatement of extinguished meth seeking in male and female rats using a BE paradigm. Correlations between meth demand and meth seeking were assessed.

RESULTS

Female rats showed greater demand (i.e., motivation) for meth compared with male rats. In both male and female rats, meth demand predicted reinstatement of meth seeking, and systemic oxytocin decreased demand for meth and attenuated reinstatement to meth seeking. Oxytocin was most effective at decreasing meth demand and seeking in rats with the strongest motivation for drug. Finally, these effects of systemic oxytocin were mediated by actions in the nucleus accumbens.

CONCLUSIONS

Oxytocin decreases meth demand and seeking in both sexes, and these effects depend on oxytocin signaling in the nucleus accumbens. Overall, these data indicate that development of oxytocin-based therapies may be a promising treatment approach for meth addiction in humans.

Use of the Exponential and Exponentiated Demand Equations to Assess the Behavioral Economics of Negative Reinforcement

Abnormal motivation and hedonic assessment of aversive stimuli are symptoms of anxiety and depression. Symptoms influenced by motivation and anhedonia predict treatment success or resistance. Therefore, a translational approach to the study of negatively motivated behaviors is needed. We describe a novel use of behavioral economics demand curve analysis to investigate negative reinforcement in animals that separates hedonic assessment of footshock termination (i.e., relief) from motivation to escape footshock. In outbred Sprague Dawley (SD) rats, relief increased as shock intensity increased. Likewise, motivation to escape footshock increased as shock intensity increased. To demonstrate the applicability to anxiety disorders, hedonic and motivational components of negative reinforcement were investigated in anxiety vulnerable Wistar Kyoto (WKY) rats. WKY rats demonstrated increased motivation for shock cessation with no difference in relief as compared to control SD rats, consistent with a negative bias for motivation in anxiety vulnerability. Moreover, motivation was positively correlated with relief in SD, but not in WKY. This study is the first to assess the hedonic and motivational components of negative reinforcement using behavioral economic analysis. This procedure can be used to investigate positive and negative reinforcement in humans and animals to gain a better understanding of the importance of motivated behavior in stress-related disorders.

The substitutability of cigarettes and food: A behavioral economic comparison in normal weight and overweight or obese smokers

Obesity and cigarette smoking contribute to a multitude of preventable deaths in the United States and eating and smoking behavior may influence each other. The field of behavioral economics integrates principles from psychology and economics and permits systematic examination of how commodities interrelate with one another. Using this framework, the current study evaluated the effects of rising food and cigarette prices on consumption to investigate their substitutability and their relationship to BMI and associated variables. Behavioral economics categorizes commodities as substitutable when the consumption of one increases as a function of a price increase in the other. Smokers (N = 86) completed a 2-part hypothetical task in which money was allocated to purchase cigarettes and fast-food-style reinforcers (e.g., hamburgers, ice cream) at various prices. Results indicated that food and cigarettes were not substitutes for one another (cross-price elasticity coefficients < .20). Food purchases were independent of cigarette price, whereas cigarette purchases decreased as food price rose. Cross-price elasticity coefficients were significantly associated with confidence in one's ability to control weight without smoking (rs = -.23 and .29), but not BMI (rs = .04 and .04) or postcessation weight concerns (rs = -.05 and .12). Perceived ability to manage weight without cigarettes may influence who substitutes food for cigarettes when quitting. In addition, given observed decreases in purchases of both commodities as food prices increased, these findings imply that greater taxation of fast-food-style reinforcers could potentially reduce consumption of these foods and also cigarettes among smokers. (PsycINFO Database Record

Clearing the haze: the complexities and challenges of research on state marijuana laws

As states increasingly liberalize marijuana laws, high-quality research is needed that will inform the public and policymakers about the health and societal impact of these laws. However, there are many challenges to studying marijuana policy, including the heterogeneity of the drug and its use, the variability in the laws and their implementation from state to state, the need to capture a wide variety of relevant outcomes, and the poorly understood influence of marijuana commercialization. Furthermore, current instruments generally fail to distinguish between types of users and lack accurate and detailed measures of use. This review provides a background on marijuana laws in the United States and an overview of existing policy research, discusses methodological considerations when planning analysis of state marijuana laws, and highlights specific topics needing further development and investigation.

Alcohol and cannabis use among college students: Substitutes or complements?

AIMS

Economists debate whether changes in availability of alcohol or cannabis are positively or negatively related to changes in use of the other substance. Implicit in these arguments are two competing, individual-level hypotheses-that people use alcohol and cannabis either as complements or substitutes for one another. This is the first study to test these hypotheses using micro-longitudinal data on individuals' alcohol and cannabis use on a given evening.

METHODS

United States college students who use alcohol and cannabis (n=876) were selected from a larger sample who participated in a 30-day online daily diary study. At baseline, students reported their proclivity to use alcohol/drugs to cope with stress. Each day students reported their level of alcohol use from the prior evening as well as whether they had used cannabis.

RESULTS

Evening levels of alcohol use and mean levels of alcohol use positively predicted the likelihood of evening cannabis use, results indicative of complementary use. This relation, however, was moderated by coping style, such that students who were more likely to use alcohol/drugs to cope were less likely to use cannabis as their evening or mean alcohol use levels increased, results indicative of substitution.

CONCLUSIONS

Substance-using college students showed evidence for complementary alcohol and cannabis use at both the within- and between-person levels. Students with a proclivity toward using alcohol/drugs to cope, however, showed evidence of substitution. These findings suggest that studies based on economic theories of substance use should take into account individual differences in substance use motives.

Explaining trends in alcohol-related harms in Scotland 1991-2011 (II): policy, social norms, the alcohol market, clinical changes and a synthesis

OBJECTIVE

To provide a basis for evaluating post-2007 alcohol policy in Scotland, this paper tests the extent to which pre-2007 policy, the alcohol market, culture or clinical changes might explain differences in the magnitude and trends in alcohol-related mortality outcomes in Scotland compared to England & Wales (E&W).

STUDY DESIGN

Rapid literature reviews, descriptive analysis of routine data and narrative synthesis.

METHODS

We assessed the impact of pre-2007 Scottish policy and policy in the comparison areas in relation to the literature on effective alcohol policy. Rapid literature reviews were conducted to assess cultural changes and the potential role of substitution effects between alcohol and illicit drugs. The availability of alcohol was assessed by examining the trends in the number of alcohol outlets over time. The impact of clinical changes was assessed in consultation with key informants. The impact of all the identified factors were then summarised and synthesised narratively.

RESULTS

The companion paper showed that part of the rise and fall in alcohol-related mortality in Scotland, and part of the differing trend to E&W, were predicted by a model linking income trends and alcohol-related mortality. Lagged effects from historical deindustrialisation and socio-economic changes exposures also remain plausible from the available data. This paper shows that policy differences or changes prior to 2007 are unlikely to have been important in explaining the trends. There is some evidence that aspects of alcohol culture in Scotland may be different (more concentrated and home drinking) but it seems unlikely that this has been an important driver of the trends or the differences with E&W other than through interaction with changing incomes and lagged socio-economic effects. Substitution effects with illicit drugs and clinical changes are unlikely to have substantially changed alcohol-related harms: however, the increase in alcohol availability across the UK is likely to partly explain the rise in alcohol-related mortality during the 1990s.

CONCLUSIONS

Future policy should ensure that alcohol affordability and availability, as well as socio-economic inequality, are reduced, in order to maintain downward trends in alcohol-related mortality in Scotland.

Racial-ethnic differences in sexual risk behaviors: The role of substance use

This research investigates the impact adolescent substance use has on adult sexual risk behaviors within racial-ethnic groups. Previous research has found support for this relationship, but often relies on concurrent measures of substance use and sexual risk behavior meaning that the causal direction of this relationship may be unclear. The data for this study come from the National Longitudinal Survey of Adolescent to Adult Health (Add Health), a nationally representative survey that followed respondents from adolescence in 1994 to adulthood in 2008. Results show that substance use correlates with sexual risk behavior, but the impact varies by race-ethnicity.

The price elasticity of demand for heroin: Matched longitudinal and experimental evidence

This paper reports estimates of the price elasticity of demand for heroin based on a newly constructed dataset. The dataset has two matched components concerning the same sample of regular heroin users: longitudinal information about real-world heroin demand (actual price and actual quantity at daily intervals for each heroin user in the sample) and experimental information about laboratory heroin demand (elicited by presenting the same heroin users with scenarios in a laboratory setting). Two empirical strategies are used to estimate the price elasticity of demand for heroin. The first strategy exploits the idiosyncratic variation in the price experienced by a heroin user over time that occurs in markets for illegal drugs. The second strategy exploits the experimentally induced variation in price experienced by a heroin user across experimental scenarios. Both empirical strategies result in the estimate that the conditional price elasticity of demand for heroin is approximately -0.80.

Economic demand predicts addiction-like behavior and therapeutic efficacy of oxytocin in the rat

Development of new treatments for drug addiction will depend on high-throughput screening in animal models. However, an addiction biomarker fit for rapid testing, and useful in both humans and animals, is not currently available. Economic models are promising candidates. They offer a structured quantitative approach to modeling behavior that is mathematically identical across species, and accruing evidence indicates economic-based descriptors of human behavior may be particularly useful biomarkers of addiction severity. However, economic demand has not yet been established as a biomarker of addiction-like behavior in animals, an essential final step in linking animal and human studies of addiction through economic models. We recently developed a mathematical approach for rapidly modeling economic demand in rats trained to self-administer cocaine. We show here that economic demand, as both a spontaneous trait and induced state, predicts addiction-like behavior, including relapse propensity, drug seeking in abstinence, and compulsive (punished) drug taking. These findings confirm economic demand as a biomarker of addiction-like behavior in rats. They also support the view that excessive motivation plays an important role in addiction while extending the idea that drug dependence represents a shift from initially recreational to compulsive drug use. Finally, we found that economic demand for cocaine predicted the efficacy of a promising pharmacotherapy (oxytocin) in attenuating cocaine-seeking behaviors across individuals, demonstrating that economic measures may be used to rapidly identify the clinical utility of prospective addiction treatments.

Efficacy of the telephone-based Brief Motivational Intervention for alcohol problems in Brazil

BACKGROUND

The Brief Motivational Intervention (BMI) is an effective treatment for alcohol misuse but has not been adequately tested for use in helplines for alcoholics. The main objective of this study was to evaluate the efficacy of a telephone-based BMI for Brazilians seeking help with alcohol use cessation.

METHODS

A randomized, controlled trial was performed with Brazilian subjects. Participants were randomly assigned to either the minimal intervention group (i.e., given reference materials) or the BMI group. Alcohol abstinence was evaluated in a 6-month follow-up telephone counseling session. The analysis was based on the intention to treat (ITT).

RESULTS

Of the 5,896 drug users who called the helpline, 700 (12%) used alcohol, 637 of whom enrolled in this study. At 6-month follow-up, 70% of the BMI group had stopped consuming alcohol compared to 41% in the control group (odds ratio = 1.5; 95% confidence interval = 1.2-1.9; p = 0.001).

CONCLUSIONS

A helpline-based BMI helps alcohol users achieve abstinence.

Demand curves for hypothetical cocaine in cocaine-dependent individuals

RATIONALE

Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks, drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated.

OBJECTIVES

This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data.

METHODS

Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use.

RESULTS

Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and O max (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, P max, were significantly correlated with real-world cocaine use.

CONCLUSIONS

Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use.

Can price get the monkey off our back? A meta-analysis of illicit drug demand

Because of the increased availability of price data over the past 15 years, several studies have estimated the demand for illicit drugs, providing 462 estimates of the price elasticity. Results from estimating several meta-regressions reveal that these price elasticity estimates are influenced by a number of study characteristics. For instance, the price elasticity differs across drugs, with its absolute value being smallest for marijuana, compared with cocaine and heroin. Furthermore, price elasticity estimates are sensitive to whether demand is modeled in the short-run or the long-run, measures of quantity and price, whether or not alcohol and other illicit drugs are included in the specification of demand, and the location of demand. However, a number of other factors, including the functional form of demand, several specification issues, the type of data and method used to estimate demand, and the quality of the publication outlet, have less influence on the price elasticity.

Spend today, clean tomorrow: predicting methamphetamine abstinence in a randomized controlled trial

OBJECTIVE

This secondary analysis of data from a randomized controlled trial tested two behavioral economics mechanisms (substitutability and delay discounting) to explain outcomes using contingency management (CM) for methamphetamine dependence. Frequency and purchase type (hedonic/utilitarian and consumable/durable) of CM payments were also examined.

METHODS

A total of 82 methamphetamine-dependent gay/bisexual men randomly assigned to conditions delivering CM received monetary vouchers in exchange for stimulant-negative urine samples in a 16-week trial requiring thrice weekly visits (Shoptaw et al., 2005). At any visit participants could redeem vouchers for goods. A time-lagged counting process Cox Proportional Hazards model for recurrent event survival analysis examined aspects of the frequency and type of these CM purchases.

RESULTS

After controlling for severity of baseline methamphetamine use and accumulated CM wealth, as measured by cumulative successful earning days, participants who redeemed CM earnings at any visit ("spenders") were significantly more likely to produce stimulant-negative urine samples in the subsequent visit, compared with those who did not redeem ("savers") 1.011* [1.005, 1.017], Z = 3.43, p < .001.

CONCLUSIONS

Findings support the economic concept of substitutability of CM purchases and explain trial outcomes as a function of frequency of CM purchases rather than frequency or accumulated total CM earnings. Promotion of frequent purchases in incentive-based programs should facilitate substitution for the perceived value of methamphetamine and improve abstinence outcomes.

Alcohol consumption and marijuana use in young adult Czechs

OBJECTIVES

The main objective of the study is to explore associations between alcohol consumption and marijuana use in young adults and to discuss the opportunities for brief intervention.

METHODS

Face to face structured interviews were carried out with 2,221 young adult Czechs (mean age 29.9, sd. 5.8 years). 51.4% were males. Alcohol consumption was calculated using beverage specific quantity frequency method. Alcohol-related problems were assessed using the Czech version of the AUDIT. Frequency of marijuana use in the last twelve months was asked as well.

RESULTS

The overall alcohol consumption was 9.2 litres of pure alcohol per person and year. The last year prevalence of marijuana use was 21.8%. The use of marijuana positively correlated with the frequency of beer drinking (r = 0.27), frequency of heavy episodic drinking [HED] (r = 0.32) and with the summary score in AUDIT (r = 0.39). Harmful or problem drinkers (AUDIT score > or = 16) reported marijuana use more frequently than moderate drinkers (60% compared to 18.8%; OR = 6.54; 95% CI = 4.7; 9.1). OR for marihuana use in heavy episodic drinkers was 4.3 (95% CI = 3.3; 5.6).

DISCUSSION

The results suggest that frequent HED and harmful drinking are closely associated with marijuana use in younger adults. Since marijuana use (including heavy use) is rather common in the Czech Republic, it would be recommendable to also extend screening and brief intervention to reduce the use of cannabis. The existing guidelines for brief intervention should be modified in order to cover marijuana consumption as well.

The behavioral economics of drug self-administration: a review and new analytical approach for within-session procedures

RATIONALE

Behavioral-economic demand curve analysis offers several useful measures of drug self-administration. Although generation of demand curves previously required multiple days, recent within-session procedures allow curve construction from a single 110-min cocaine self-administration session, making behavioral-economic analyses available to a broad range of self-administration experiments. However, a mathematical approach of curve fitting has not been reported for the within-session threshold procedure.

OBJECTIVES

We review demand curve analysis in drug self-administration experiments and provide a quantitative method for fitting curves to single-session data that incorporates relative stability of brain drug concentration.

METHODS

Sprague-Dawley rats were trained to self-administer cocaine, and then tested with the threshold procedure in which the cocaine dose was sequentially decreased on a fixed ratio-1 schedule. Price points (responses/mg cocaine) outside of relatively stable brain cocaine concentrations were removed before curves were fit. Curve-fit accuracy was determined by the degree of correlation between graphical and calculated parameters for cocaine consumption at low price (Q(0)) and the price at which maximal responding occurred (P(max)).

RESULTS

Removing price points that occurred at relatively unstable brain cocaine concentrations generated precise estimates of Q(0) and resulted in P (max) values with significantly closer agreement with graphical P(max) than conventional methods.

CONCLUSION

The exponential demand equation can be fit to single-session data using the threshold procedure for cocaine self-administration. Removing data points that occur during relatively unstable brain cocaine concentrations resulted in more accurate estimates of demand curve slope than graphical methods, permitting a more comprehensive analysis of drug self-administration via a behavioral-economic framework.

Race/ethnicity differences between alcohol, marijuana, and co-occurring alcohol and marijuana use disorders and their association with public health and social problems using a national sample

BACKGROUND

Alcohol and marijuana are commonly used and misused in the United States, both singly and together. Despite this, few studies examine their co-occurring use and the corresponding association with public health and other problems. Moreover, there is a lack of investigation into differences in these associations on the basis of race/ethnicity.

METHODS

The present study estimated the frequency of alcohol use disorder, marijuana use disorder, and co-occurring alcohol and marijuana use disorder and their associated public health and social problems in Whites, African Americans, and Hispanics. This cross-sectional study included 13,872 individuals and used data from the 2005-2007 National Survey on Drug Use and Health. Frequency was calculated and multinomial regression was used to assess associations between substance use disorder and psychosocial, adverse consequences such as history of being arrested, substance use treatment, and sexually transmitted infection.

RESULTS

Alcohol use disorder was comparable between, and most prevalent among, Whites and Hispanics compared to African Americans, whereas marijuana use disorder was greatest among African Americans compared to other race/ethnicities. Co-occurring alcohol and marijuana use disorders were most prevalent for African Americans versus Whites and Hispanics, and similar in Whites and Hispanics. In general, major depressive episode was more prevalent for respondents with co-occurring use disorders or single marijuana use disorders. However, race/ethnicity differences in associations between substance use disorder and psychosocial correlates and adverse consequences were observed.

CONCLUSIONS

Findings have implications for race/ethnicity appropriate integrated prevention and treatment of single and co-occurring use disorders and psychiatric comorbidities.

Effects of economy type and nicotine on the essential value of food in rats

The exponential demand equation proposed by Hursh and Silberberg (2008) provides an estimate of the essential value of a good as a function of price. The model predicts that essential value should remain constant across changes in the magnitude of a reinforcer, but may change as a function of motivational operations. In Experiment 1, rats' demand for food across a sequence of fixed-ratio schedules was assessed during open and closed economy conditions and across one- and two-pellet per reinforcer delivery conditions. The exponential equation was fitted to the relation between fixed-ratio size and the logarithm of the absolute number of reinforcers. Estimates of the rate of change in elasticity of food, the proposed measure of essential value, were compared across conditions. Essential value was equivalent across magnitudes during the closed economy, but showed a slight decrease across magnitudes during the open economy. Experiment 2 explored the behavioral mechanisms of nicotine's effects on consumption with the results from Experiment 1 serving as a within-subject frame of reference. The same subjects were administered nicotine via subcutaneously implanted osmotic minipumps at a dose of 3 mg/kg/day and exposed to both the one- and two-pellet conditions under a closed economy. Although nicotine produced large decreases in demand, essential value was not significantly changed. The data from the present experiments provide further evidence for the adequacy of the exponential demand equation as a tool for quantifying the rate of change in elasticity of a good and for assessing behavioral mechanisms of drug action.

Poor impulse control predicts inelastic demand for nicotine but not alcohol in rats

Tobacco and alcohol dependence are characterized by continued use despite deleterious health, social and occupational consequences, implying that addicted individuals pay a high price for their use. In behavioral economic terms, such persistent consumption despite increased costs can be conceptualized as inelastic demand. Recent animal studies demonstrated that high-impulsive individuals are more willing to work for nicotine or cocaine infusions than their low-impulsive counterparts, indicating that this trait might be causally related to inelastic drug demand. By employing progressive ratio schedules of reinforcement combined with a behavioral economics approach of analysis, we determined whether trait impulsivity is associated with an insensitivity of nicotine or alcohol consumption to price increments. Rats were trained on a delayed discounting task, measuring impulsive choice. Hereafter, high- and low-impulsive rats were selected and trained to nose poke for intravenous nicotine or oral alcohol. Upon stable self-administration on a continuous reinforcement schedule, the price (i.e. response requirement) was increased. Demand curves, depicting the relationship between price and consumption, were produced using Hursh's exponential demand equation. Similar to human observations, nicotine and alcohol consumption in rats fitted this equation, thereby demonstrating the validity of our model. Moreover, high-impulsive rats displayed inelastic nicotine demand, as their nicotine consumption was less sensitive to price increments as compared with that in low-impulsive rats. Impulsive choice was not related to differences in alcohol demand elasticity. Our model seems well suited for studying nicotine and alcohol demand in rats and, as such, might contribute to our understanding of tobacco and alcohol dependence.

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 drug's 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.