PROJECT SUMMARY/ABSTRACT In 2020, 28.3 million Americans experienced an alcohol use disorder (AUD); yet only 25% of these people received treatment. During the pandemic, 60% of patients with a substance use disorder reported receiving telehealth-based care for their addiction. The pivot to telehealth provides an opportunity to overcome the barriers to access and retention that affect in-person care (e.g., inconvenience, stigma). In contingency management (CM), people receive tangible reinforcers in exchange for submitting biological samples to verify abstinence. CM is ideal for telehealth delivery and initial studies of telehealth models demonstrated reductions in alcohol use. At the same time, these models have limitations. They require wearing a transdermal monitor or submitting multiple breath samples daily. As a result, these approaches are costly, burdensome, and stigmatizing which limits their feasibility. In part due to limitations of these biomarkers, current CM models are brief, averaging about 12 weeks, despite evidence suggesting that longer CM interventions result in better post-treatment outcomes. Therefore, the overall objective of our program of research is to utilize phosphatidylethanol (PEth), a blood-based biomarker that can detect alcohol use for up to 28 days to deliver a feasible telehealth-based 26-week CM intervention. In a pilot trial, we developed a telehealth-based PEth CM intervention where participants used a medical device, the TASSO-M20 to self-collect blood for PEth testing under the observation of research staff over Zoom. This intervention used a two-phase approach where the frequency of PEth testing and reinforcement was decreased from once a week, to as infrequently as every four weeks once participants achieved a PEth level consistent with two to four weeks of abstinence (< 20 ng/mL). Seventy-one percent of CM participants achieved >4 weeks of abstinence versus 21% of the treatment as usual (TAU) group, and 43% of CM participants achieved >24 weeks of abstinence compared to 0% of the TAU group (p < 0.05). Based on these promising results, we now propose to test our telehealth PEth-based CM model in a sample of adults with AUD (n=200), recruited via online platforms by randomizing individuals to six months of 1) an online cognitive behavioral therapy for AUD (CBT4CBT) and telehealth PEth-based CM (CM condition) or 2) CBT4CBT and reinforcers for submitting blood samples (no abstinence required) (control condition). We will assess group differences in PEth-defined abstinence and regular excessive drinking (PEth ³ 200 ng/mL), and alcohol-related harms (e.g., smoking, drug use). We will address important gaps in CM research by assessing outcomes during a 12-month follow-up, which is much longer than most previous CM studies; using a conceptual model to identify predictors of post-treatment abstinence. The primary barrier to the dissemination of our model is the cost of PEth testing and CM reinforcers. We will conduct an economic analysis to place these costs in the context of downstream CM-associated cost- offsets and improvements in personal and public health. If our model increases alcohol abstinence and is cost- effective it could reach millions of Americans with AUD that cannot or do not seek in-person care.

PROJECT RELEVANCE Ten percent of Americans meet criteria for an alcohol use disorder, with rising levels of problematic drinking during the COVID-19 pandemic. Novel strategies, including leveraging telehealth, are needed to bring effective interventions to the millions of people in the US who experience problems with alcohol. We propose to investigate the efficacy and cost-effectiveness of an incentive intervention called contingency management that will be delivered via telehealth using a novel alcohol biomarker called phosphatidylethanol (PEth), and we will also identify factors that predict long-term abstinence during a 12-month follow-up period.