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

Abstract

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 heavydrinking 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.

Leveraging behavioral economics and reinforcement theory in treating heavy episodic drinking among college students

“…A notable and consistent result across these prior studies and the results reported by Murphy et al (2021) is that the frequency of engagement with alternative nonsubstance-related activities and not the ability to experience enjoyment from those activities is what differentiates those with substance use disorders from controls. Also important to note is that the study by Rogers et al (2008) mentioned above was experimental and demonstrated that a contingency-management intervention that reinforced abstinence from cocaine and opiate use increased not only abstinence from drug use but also the frequency of engagement in nonsubstancerelated activities, an observation that also aligns well with the results reported by Murphy et al (2019Murphy et al ( , 2021.…”

“…While only a limited number of studies have examined the PES in relation to substance use, the instrument has nevertheless been demonstrated to be quite effective in characterizing an inverse relationship between engagement in nonsubstance-related activities and drinking and other substance use across multiple populations including college students (Correia et al, 2003), psychiatric patients (Correia & Carey, 1999), outpatients with cocaine use disorder (Van Etten et al, 1998), and outpatients with comorbid cocaine and opioid use disorders (Rogers et al, 2008). A notable and consistent result across these prior studies and the results reported by Murphy et al (2021) is that the frequency of engagement with alternative nonsubstance-related activities and not the ability to experience enjoyment from those activities is what differentiates those with substance use disorders from controls. Also important to note is that the study by Rogers et al (2008) mentioned above was experimental and demonstrated that a contingency-management intervention that reinforced abstinence from cocaine and opiate use increased not only abstinence from drug use but also the frequency of engagement in nonsubstancerelated activities, an observation that also aligns well with the results reported by Murphy et al (2019Murphy et al ( , 2021.…”

“…In this follow-up study, Murphy et al (2021) used the Reward Probability Index (RPI) questionnaire, a validated 20-item instrument for quantifying environmental reward activity and enjoyment (Carvalho et al, 2011), to identify distinct sample subgroups with regard to changes in engagement with environmental rewards across the 16-month study period, associations between those activity patterns and alcohol severity (a latent factor derived from several measures of alcohol use and related problems), predictors of membership in the distinct trajectory subgroupings, and differences between subgroupings in treatment response. Participants fell into two distinct trajectories of reward accessibility, with 30.5% of participants falling into a trajectory characterized by a relatively low but increasing amount of reward accessibility over time (LR), and a second trajectory involving the remaining 69.5% of participants who reported relatively high levels of reward accessibility (HR) that remained relatively stable throughout the 16-month study period.…”

“…Of course, like all studies, the study by Murphy et al (2021) is not without limitations. I will briefly mention three.…”

“…While perhaps an easy notion to state abstractly, translating such knowledge into effective clinical action can be more challenging. Thus, I am thrilled to have this opportunity to comment on a report by Murphy and colleagues (Murphy et al, 2021) in Alcoholism: Clinical & Experimental Research that provides an excellent example of just such a translation. Murphy et al (2021) report results from an innovative and rigorous secondary analysis of a randomized clinical trial involving 393 heavy drinking college students randomly assigned to one of the three conditions: (1) an assessment-only (AO) control condition;…”