Contextual and psychosocial factors influencing drug reward in humans: The importance of non-drug reinforcement

The reinforcing efficacy, or behavior-strengthening effect, of a substance is a critical determinant of substance use typically quantified by measuring behavioral allocation to the substance under schedules of reinforcement with escalating response requirements. Although responses on these tasks are often used to indicate stable reinforcing effects or trait-level abuse potential for an individual, task designs often demonstrate within-person variability across varying degrees of a constraint within experimental procedures. As a result, quantifying behavioral allocation is an effective approach for measuring the impact of contextual and psychosocial factors on substance reward. We review studies using laboratory self-administration, behavioral economic purchase tasks, and ambulatory assessments to quantify the impact of various contextual and psychosocial factors on behavioral allocation toward consumption of a substance. We selected these assessment approaches because they cover the translational spectrum from experimental control to ecological relevance, with consistent support across these approaches representing greater confidence in the effect. Conceptually, we organized factors that influence substance value into two broad categories: factors that influence the cost/benefit ratio of the substance (social context, stress and affect, cue exposure), and factors that influence the cost/benefit ratio of an alternative (alternative non-drug reinforcers, alternative drug reinforcers, and opportunity costs). We conclude with an overview of future research directions and considerations for clinical application.

Independent and concurrent cannabis use with alcohol, cigarettes, and other substances among college students: Rates and consequences

Objective: The purpose of this study was to examine patterns of concurrent cannabis and other substance use and their differential associations with cannabis-related problems and academic outcomes in college students. Participants: Participants were undergraduate students (N = 263; M age = 19.1 years; 61.2% female) who were eligible if they used cannabis at least 3 days in the past month (M = 10.1 days). Method: Substance use, academic-related outcomes, and measures of Cannabis Use Disorder (CUD) severity and problems were obtained in an online survey. Results: The five groups evaluated were cannabis-only users (5.3%), cannabis and alcohol (47.1%), cannabis, alcohol and cigarettes (16.7%), cannabis, alcohol and other substances (14.8%), or all-substances (16%). Cannabis-only and all-substance users reported using cannabis most frequently (ps ≤ .034), but only the latter reported greater CUD severity, problems, and poorer academic outcomes. Discussion: College student polysubstance users may be at increased risk for poorer outcomes compared to cannabis-only users and other groups.

A brief measure of non-drug reinforcement: Association with treatment outcomes during initial substance use recovery

BACKGROUND

Translational research demonstrates that drug use is inversely associated with availability and engagement with meaningful non-drug reinforcers. Evaluation of non-drug reinforcement in treatment-receiving clinical populations is limited, likely owing to the time intensive nature of existing measures. This study explores the association of non-drug reinforcers with treatment outcomes using a novel, brief measure of past month non-drug reinforcement quantifying three elements: relative frequency, access, and enjoyability.

METHODS

Respondents enrolled in substance use treatment (residential, intensive outpatient, and medically managed withdrawal) in clinics across the United States (N = 5481) completed standardized assessments of non-drug reinforcement and treatment outcomes (i.e., return to use and life satisfaction) one-month after treatment discharge. Non-drug reinforcement measures (availability, engagement, enjoyability) were used as predictors of return to use and life satisfaction using generalized linear models.

RESULTS

Non-drug reinforcement indices were associated with return to use and life satisfaction in unadjusted models (e.g., 12.4 % versus 58.3 % return to use for those with the highest and lowest availability, respectively). Consistent results were observed in models adjusted for sociodemographic variables and risk factors (i.e., sleep disturbance, anhedonia, stress). Comparisons by drug class generally showed lower non-drug reinforcement among patients reporting heroin or methamphetamine as their primary drug.

CONCLUSIONS

Results highlight the importance of non-drug reinforcement during the first month following treatment. Rapid measurement of non-drug reinforcement in stepped care settings may illuminate critical deficits in early stages of behavior change, identify those at greatest risk for return to use, and provide targets for treatment to improve recovery trajectories.

A contextualized reinforcer pathology approach to addiction

Behavioural economic accounts of addiction conceptualize harmful drug use as an operant reinforcer pathology, emphasizing that a drug is consumed because of overvaluation of smaller immediate rewards relative to larger delayed rewards (delay discounting) and high drug reinforcing value (drug demand). These motivational processes are within-individual determinants of behaviour. A third element of learning theory posits that harmful drug use depends on the relative constraints on access to other available activities and commodities in the choice context (alternative reinforcers), reflecting the substantial influence of environmental factors. In this Perspective, we integrate alternative reinforcers into the contemporary behavioural economic account of harmful drug use - the contextualized reinforcer pathology model - and review empirical literature across the translational spectrum in support of this model. Furthermore, we consider how increases in drug-related mortality and health disparities in addiction can be understood and potentially ameliorated via a contextualized reinforcer pathology model in which lack of alternative reinforcement is a major risk factor for addiction.

Associations between Alcohol-Free Sources of Reinforcement and the Frequency of Alcohol and Cannabis Co-Use among College Freshmen

Co-use of alcohol and cannabis is common among young adults in the United States. A behavioral economics framework indicates that greater engagement in substance-free sources of reinforcement may be protective against co-use frequency. The current study tested the association between proportionate alcohol-free reinforcement and the frequency of co-use among college freshmen. Participants (N = 86) were freshmen who enrolled in a freshman orientation course and completed surveys at the beginning of the semester. Past month alcohol use, cannabis use, and reinforcement from alcohol-free and alcohol-involved activities were assessed. A zero-inflated Poisson regression was used to test the association between proportionate alcohol-free reinforcement and days of co-use. The results indicated that proportionate alcohol-free reinforcement was negatively associated with co-use days in the count model when controlling for alcohol use days and gender as covariates (β: -3.28, p = 0.016). Proportionate alcohol-free reinforcement did not significantly differentiate individuals who did not engage in co-use in the zero-inflated model (β: -1.68, p = 0.497). The study suggested that greater proportionate alcohol-free reinforcement may be associated with lower engagement in the co-use of alcohol and cannabis among young adults. Increasing engagement in alcohol-free sources of reinforcement may be considered a target for co-use prevention or harm reduction efforts.

Associations of Social Capital with Mental Disorder Prevalence, Severity, and Comorbidity among U.S. Adolescents

OBJECTIVE

To examine cross-sectional associations between social capital constructs and 1) adolescent lifetime mental disorders, 2) severity of functional impairment, and 3) psychiatric comorbidity.

METHOD

Data were from the National Comorbidity Survey Adolescent Supplement, a nationally representative mental health survey of 6,483 U.S. adolescents aged 13-18 years. Information from fully-structured diagnostic interviews, including adolescent and caregiver reports, was used to measure seven social capital constructs and lifetime DSM-IV mental disorders (mood, anxiety, behavior, substance use and eating disorder classes). Disorder severity was divided into severe vs. mild/moderate. Comorbidity was measured as the number of different classes of lifetime mental disorders.

RESULTS

Adjusted for socio-demographics and caregivers' mental health, the most consistent associations with adolescent mental disorder were for supportive friendships (any disorder OR = 0.95, 95%CI = 0.91-0.99), family cohesion (OR = 0.81, 95%CI = 0.75-0.86), school bonding (OR = 0.76, 95%CI = 0.71-0.81), and extracurricular participation (OR = 0.90, 95%CI = 0.86-0.95), although results differed by disorder class. Caregiver-reported neighborhood trust and reciprocity and caregiver community involvement were less consistently associated with mental disorder. Medium levels of adolescent-reported affiliation with neighbors was associated with lower odds of mood (OR = 0.81, 95%CI = 0.66-0.98) and anxiety (OR = 0.78, 95%CI = 0.64-0.96) disorder, while high levels were associated with higher odds of behavior disorder (OR = 1.47, 95%CI = 1.16-1.87). Several associations were stronger for severe vs. mild/moderate disorder and with increasing comorbidity.

CONCLUSION

Although we cannot infer causality, our findings support the notion that improving actual and/or perceived social capital, especially regarding friendships, family, and school, (e.g., through multimodal interventions) could aid in the prevention and treatment of both individual adolescent mental disorders and psychiatric comorbidity.

Tobacco and cannabis use as moderators of the association between physical activity and alcohol use across the adult lifespan in the United States: NHANES, 2005-2016

Physically-active adults are more likely to consume alcohol, but this association may vary if adults also use other substances (i.e., tobacco and/or cannabis), which could increase substance-use related harms. This study examined whether tobacco and/or cannabis use moderated the associations between physical activity, odds of drinking and alcohol drinks/week. We used cross-sectional 2005-2016 National Health and Nutrition Examination Survey data (United States of America). Physical activity was assessed using device-based and self-reported moderate-to-vigorous physical activity (MVPA) and total physical activity hours/week. Individuals were categorized into one of four (poly)substance use categories, no tobacco/no cannabis, tobacco, cannabis, or tobacco/cannabis use. Regression models examined substance use as a moderator of the association between physical activity and the odds of drinking versus not drinking and alcohol drinks/week among light/moderate/heavy drinkers (≥12 drinks/year). Using cannabis or tobacco weakened the significant positive associations between total physical activity and self-reported recreational MVPA hours/week on odds of drinking (ORs = 0.978 and 0.967, respectively), such that the effect was negative or null when using cannabis or tobacco, respectively. Greater total physical activity and device-based MVPA hours/week was associated with consuming greater drinks/week (IRRs = 1.003 and 1.035, respectively). Using tobacco weakened the association between device-based MVPA and alcohol drinks/week (IRR = 0.934, 95% CI: [0.888, 0.982]). Cannabis and tobacco use weakened the association between physical activity and alcohol use. The positive association between physical activity and alcohol use may be limited to single substance users of alcohol and could reflect shared reasons for engaging in these behaviors, such as stress management or social motives.

Daily Physical Activity, Sedentary Behavior and Alcohol Use in At-Risk College Students

BACKGROUND

The college years present an opportunity to establish health behavior patterns that can track across adulthood. Health behaviors tend to cluster synergistically however, physical activity and alcohol have shown a positive association.

PURPOSE

This study applied a multi-method approach to estimate between- and within-person associations between daily physical activity, sedentary behavior and alcohol use among polysubstance-using college students.

METHODS

Participants were screened for recent binge drinking and either tobacco or cannabis use. They wore an activPAL4 activity monitor and a Secure Continuous Remote Alcohol Monitor continuously in the field for 11 days, and completed daily online questionnaires at the beginning of each day to report previous day physical activity, sedentary behavior, and alcohol consumption.

RESULTS

Participants (N = 58, Mage = 20.5 years, 59% women, 69% White) reported meeting national aerobic physical activity guidelines (75%) and drinking 2-4 times in the past month (72%). On days when participants reported an hour more than usual of daily sedentary behavior, they reported drinking for less time than usual (γ = -.06). On days when participants took 1,000 more steps than usual, the longest episode of continuous transdermal alcohol detection was shorter (γ = -.03).

CONCLUSIONS

Daily physical activity and sedentary behavior were negatively associated with time-based measures of alcohol use with the lowest risk on days characterized by both activity and sedentary behavior. Intensive longitudinal monitoring of time-based processes can provide new insights into risk in multiple behavior change and should be prioritized for future work.

Trajectories of reward availability moderate the impact of brief alcohol interventions on alcohol severity in heavy-drinking young adults

BACKGROUND

Behavioral economic theory predicts that low access to environmental reward is a risk factor for alcohol use disorder (AUD). The Substance-Free Activity Session (SFAS) is a behavioral economic supplement to standard brief alcohol interventions that attempts to increase environmental reward and may therefore have beneficial effects, particularly for individuals with low levels of environmental reward.

METHODS

Participants were 393 college students who reported at least 2 heavy-drinking episodes in the past month. Participants were randomly assigned to 1 of 3 conditions following a baseline assessment: a standard alcohol-focused brief motivational intervention plus relaxation training session (BMI + RT), BMI plus Substance-Free Activity Session (BMI + SFAS), or an assessment-only control condition (AO). In a secondary analysis of the data from this study, we used person-centered statistical techniques to describe trajectories of alcohol severity and environmental reward over a 16-month follow-up and examined whether environmental reward levels moderated the effectiveness of the interventions.

RESULTS

Piecewise growth mixture modeling identified 2 trajectories of reward availability: low increasing (LR; n = 120) and high stable (HR; n = 273). Depressive symptoms, cannabis use, sensation seeking, and low life satisfaction were associated with a greater probability of classification in the LR trajectory. Alcohol severity was greater in the LR trajectory than the HR trajectory. For students in the LR trajectory, at 1, 6, and 12 months, BMI + SFAS led to greater increases in reward availability and reduced levels of alcohol severity compared with the BMI + RT and AO conditions and at 16 months compared with AO.

CONCLUSIONS

Young adults with low levels of environmental reward are at heightened risk for greater alcohol severity and may show greater benefit from brief alcohol interventions that focus on increasing substance-free reward than individuals who are not deficient in reward availability.

Reducing drug-use harms among higher education students: MyUSE contextual-behaviour change digital intervention development using the Behaviour Change Wheel

BACKGROUND

Digital harm-reduction interventions typically focus on people with severe drug-use problems, yet these interventions have moderate effectiveness on drug-users with lower levels of risk of harm. The difference in effectiveness may be explained by differences in behavioural patterns between the two groupings. Harnessing behavioural theories to understand what is at the core of drug-use behaviours and mapping the content of new interventions, may improve upon the effectiveness of interventions for lower-risk drug-users. To the best of our knowledge, this is the first study to systematically apply the Behaviour Change Wheel (BCW) approach to understand the components, influencing capabilities, opportunities, and motivations (COM-B) of higher education students to change their drug-use behaviors. It is also the first study which identifies specific patterns of behaviours that are more responsive to harm reduction practices through the use of the Theoretical Domain Framework (TDF).

METHODS

We employed an explanatory sequential mix-method design. We first conducted an on-line survey and a Delphi exercise to understand the factors influencing COM-B components of higher education students to change their drug-use. Subsequently, we mapped all evidence onto the COM-B components and the TDF domains to identify clusters of behaviours to target for change, using a pattern-based discourse analysis. Finally, a series of multidisciplinary group meetings identified the intervention functions-the means by which the intervention change targeted behaviours and the Behavioural Change Techniques (BCTs) involved using the behaviour change technique taxonomy (v.1).

RESULTS

Twenty-nine BCTs relevant to harm-reduction practices were identified and mapped across five intervention functions (education, modelling, persuasion, incentivization, and training) and five policy categories (communication/marketing, guidelines, regulation, service provision, and environmental/social planning). These BCTs were distributed across eight identified saturated clusters of behaviours MyUSE intervention attempts to change.

CONCLUSIONS

The BCTs, identified, will inform the development of a digitally delivered behaviour change intervention that focuses on increasing mindful decision-making with respect to drug-use and promotes alternatives to drug-use activities. The findings can also inform implementation scientists in applying context-specific harm-reduction practices in higher education. We present examples of how the eight identified clusters of target behaviours are mapped across the COM-B components and the TDF, along with suggestions of implementation practices for harm reduction at student population level.

Cannabis use in college: Genetic predispositions, peers, and activity participation

BACKGROUND

Among adult college students in the US, cannabis use is common and associated with considerable negative consequences to health, cognition, and academic functioning, underscoring the importance of identifying risk and protective factors. Cannabis use is influenced by genetic factors, but genetic risk is not determinative. Accordingly, it is critical to identify environments that reduce risk among those who are at elevated genetic risk. This study examined the impact of polygenic scores for cannabis initiation, various forms of social activity participation, and peer deviance on recent cannabis use. Our aim was to test whether these environments moderate genetic risk for cannabis use.

METHODS

Data came from a longitudinal sample of undergraduate college students of European American (EA; NEA = 750) and African American (AA; NAA = 405) ancestry. Generalized estimating equations with a logit link function were used to examine main effects and two-way interactions.

RESULTS

Engagement with church activities was associated with lower probability of cannabis use. Peer deviance was associated with higher probability of cannabis use. Engagement with community activities moderated the influence of the polygenic risk score in the EA sample, such that PRS was associated with recent cannabis use among those who never engaged in community activities. This effect did not replicate in AAs, which may have been due to the portability of PRS based on EA discovery samples.

CONCLUSIONS

Results suggest that community activities may limit the influence of genetic risk, as associations between PRS and cannabis use were only observed among individuals who never engaged in community activities.

How do college students use their free time? A latent profile analysis of leisure activities and substance use

College is a critical period of transition to independence and the substantial amount of time that students have to participate in leisure activities may be conducive to substance use. However, little is known about the associations between leisure activities and substance use over time, or whether these associations differ by residential status (i.e., living with parents vs. on their own). Using latent profile analysis, this study found six distinct profiles of leisure activity participation in a racially/ethnically diverse sample of college students (N=1,207). Overall, profiles with medium levels of leisure activity participation were associated with more alcohol use, heavy drinking, and marijuana use one year later; whereas profiles with the lowest levels of leisure activity participation were associated with more cigarette use one year later. Identifying mechanisms through which leisure activities influence substance use can help inform prevention efforts to either reduce risks associated with participation or support protective effects.

A systematic review of physical activity, sedentary behavior, and substance use in adolescents and emerging adults

The transition from adolescence into emerging adulthood is marked by changes in both physical activity and substance use. This systematic review characterized associations between movement behaviors (physical activity, sedentary behavior) and frequently used substances (alcohol, cannabis) among adolescents and emerging adults to inform lifestyle interventions that target multiple behavior change outcomes. This systematic review was guided by PRISMA. Electronic databases of PubMed, PsycINFO, and Web of Science were searched from inception through June 25, 2019. The search was designed to identify empirical studies reporting an association between physical activity or sedentary behavior and alcohol or cannabis, with search criteria determining eligibility based on several sampling characteristics (e.g., participants under 25 years of age). After identifying and screening 5,610 studies, data were extracted from 97 studies. Physical activity was positively associated with alcohol use among emerging adults, but the literature was mixed among adolescents. Sedentary behavior was positively associated with alcohol and cannabis use among adolescents, but evidence was limited among emerging adults. Self-report measures were used in all but one study to assess these behaviors. Physical activity is linked to greater alcohol use among emerging adults. Whereas existing studies demonstrate that sedentary behavior might serve as a risk marker for alcohol and cannabis use among adolescents, additional primary research is needed to explore these associations in emerging adults. Future work should also use device-based measures to account for timing of and contextual features surrounding activity and substance use in these populations.

Comparing American college and noncollege young adults on e-cigarette use patterns including polysubstance use and reasons for using e-cigarettes

Objective: Existing literature on young adults' e-cigarette and polysubstance use focused on college students. This study examined the differences between college and noncollege groups on prevalence and patterns of e-cigarette and other substance use using data from a national survey. Participants: Adults aged 18-24 from the 2013-2014 Population Assessment of Tobacco and Health Study (n = 6,608). Methods: Independent sample t-tests and Chi-square tests were conducted to examine group differences. Results: Noncollege young adults had higher prevalence of cigarette, e-cigarette, and marijuana use; college students had higher prevalence of alcohol use. Among current e-cigarette users, college students had higher prevalence of polysubstance use of alcohol and marijuana. College students used e-cigarettes for socializing purposes more. Conclusions: Differences in prevalence and patterns of e-cigarette and other substance use between college and noncollege groups exist. Future interventions should target the social context of college life and reach out to noncollege young adults in workplaces.

Measurement of substance-free reinforcement in addiction: A systematic review

A robust body of theoretical and experimental work highlights the influence of alternative, substance-free rewards on decisions to use alcohol and other drugs. However, translational applications have been limited in part by the lack of consensus on how to measure substance-free reinforcement in applied and clinical settings. The current study summarizes extant research utilizing self-report reinforcement or reward methodologies, and critically reviews the psychometric properties of the available measures. These studies (N = 50) fell into three categories: measures of recent substance-related and substance-free activity participation and enjoyment (n = 32), measures of time or monetary resource allocation (n = 15), and rating scale measures of reward availability and experience (n = 8). The available research suggests that, consistent with experimental laboratory research and with behavioral economic predictions, there is an inverse relation between substance-free reinforcement and substance use. These studies also support the clinical utility of these measures in predicting substance use severity and course. Reinforcement measures could be improved by enhancing content validity, multimethod convergent validity, and generalizability.

'Higher education' - substance use among Berlin college students

Berlin is internationally known for its intense nightlife associated with high rates of psychoactive substance use. Previous studies conducted in other cities indicated college students as a group at high risk for substance (mis-)use that was associated with individual psychological and cognitive impairments as well as lower academic performance. The aim of this study was to provide detailed data about the substance use patterns of Berlin college students. In addition, major protective and risk factors were analysed. An online questionnaire assessing sociodemographic data and various relevant aspects of both legal and illegal substance use such as consumption pattern and frequency as well as risk-taking behaviour was developed and distributed among colleges in Berlin. A sample of 9351 participants from 17 different colleges in Berlin completed the questionnaire. The study revealed high lifetime (69.3%), past year (45.9%) and past month (28.3%) prevalence of illicit substance use in the sample. Daily tobacco-smoking, a mental disorder diagnosis, a positive screening for problematic consumption (Cage-AID), bisexual orientation and living in open relationship were main factors positively associated with the prevalence and the extent of illicit substance use. Students in Berlin appear to show higher rates of illicit substance use than was previously reported for age-matched individuals in the general German population and college students in other cities. Thus, they are a relevant target group for early prevention and intervention concerning substance use and abuse.

A three-city comparison of drug use and drug use before sex among young men who have sex with men in the United States

High rates of drug use have been documented among young men who have sex with men (YMSM). However, updated prevalence data are needed to understand current trends, especially for drug use before sex. We used baseline data from an HIV prevention trial to examine demographic differences in drug use (in general and before sex) among YMSM in Atlanta, Chicago, and NYC. Marijuana was the most commonly used drug, but alkyl nitrites ("poppers"), cocaine, and Ecstasy were also common. Drug use was more prevalent among older and White YMSM, and it was similar between cities, except use of poppers was higher in NYC. Our data generally support national prevention efforts.

Deficits in Access to Reward Are Associated with College Student Alcohol Use Disorder

BACKGROUND

Reward deprivation has been implicated in major depressive disorder and severe substance abuse, but its potential relation to alcohol use disorder (AUD) symptoms in non-treatment-seeking young adult drinkers is less clear. Depression is often comorbid with alcohol misuse, so relations of AUD with reward deprivation might be due in part to the presence of depressive symptoms in young adults. Behavioral economic theory views addiction as a state that is related in part to deficits in drug-free rewards, and therefore requires an investigation into whether reward deprivation has a direct relation to alcohol misuse that is, at least partially, independent of mood.

METHODS

This study evaluates the contribution of 2 facets of reward deprivation (reward availability and experience) to alcohol use, AUD symptoms, and depression in a sample of young adult heavy episodic drinkers. Data were collected from 392 undergraduates (60.4% female, 85.1% Caucasian) who reported recent heavy drinking (83.7% with at least 1 AUD symptom).

RESULTS

Low reward availability (environmental suppression) was significantly associated with both DSM-5 AUD symptoms and alcohol-related problems after controlling for age, gender, depressive symptomatology, and drinking level.

CONCLUSIONS

This study provides support for behavioral economic models that emphasize reward deprivation as a unique risk factor for AUD that is independent of mood and drinking level. Limited access to natural rewards may be a risk and/or maintaining factor for AUD symptoms in college student drinkers.

The behavioral economics of young adult substance abuse

Alcohol and drug use peaks during young adulthood and can interfere with critical developmental tasks and set the stage for chronic substance misuse and associated social, educational, and health-related outcomes. There is a need for novel, theory-based approaches to guide substance abuse prevention efforts during this critical developmental period. This paper discusses the particular relevance of behavioral economic theory to young adult alcohol and drug misuse, and reviews of available literature on prevention and intervention strategies that are consistent with behavioral economic theory. Behavioral economic theory predicts that decisions to use drugs and alcohol are related to the relative availability and price of both alcohol and substance-free alternative activities, and the extent to which reinforcement from delayed substance-free outcomes is devalued relative to the immediate reinforcement associated with drugs. Behavioral economic measures of motivation for substance use are based on relative levels of behavioral and economic resource allocation towards drug versus alternatives, and have been shown to predict change in substance use over time. Policy and individual level prevention approaches that are consistent with behavioral economic theory are discussed, including brief interventions that increase future orientation and engagement in rewarding alternatives to substance use. Prevention approaches that increase engagement in constructive future-oriented activities among young adults (e.g., educational/vocational success) have the potential to reduce future health disparities associated with both substance abuse and poor educational/vocational outcomes.