ABSTRACT There is an urgent need to develop novel pharmacological treatment for alcohol use disorder (AUD). Recently, psychedelic compounds have attracted great attention in treatment of different psychiatric disorders following their reported fast-acting and long-lasting effects. Preliminary evidence from observational studies, supported by animal studies, is promising for the potential therapeutic effects of psychedelic N,N-dimethyltryptamine (DMT) for AUD. Here, we propose to investigate the therapeutic potential of a single dose of intravenous DMT plus a brief course of psychotherapy (including Motivational Enhancement Therapy (MET)) on alcohol consumption in non-treatment seeking individuals with AUD, in a proof-of-concept, randomized (1:1), placebo- controlled, double-blind, parallel group, laboratory study and clinical trial. Methods: Otherwise healthy individuals with diagnosis of moderate to severe AUD (based on DSM5) will be randomized to receive a single dose of intravenous DMT or active placebo (diphenhydramine). Vitals will be closely monitored, tolerability will be measured using a Visual Analogue Scale (VAS), and DMT acute psychedelic effects will be assessed using the Mystical Experience Questionnaire (MEQ), at the end of the dosing day. Adverse events will be assessed using the Systematic Assessment for Treatment Emergent Effects (SAFTEE) interview on the dosing day and weekly follow up sessions (4 weeks). One day following drug administration, participants will attend an experimental session using Alcohol Drinking Paradigm (ADP). All participants will consume a priming dose of alcohol at the beginning of the experimental session, which will be followed by two 1-hour self-administration drinking sessions, over which participants will have a choice of consuming a total of 8 drinks or receiving $5 for each drink that is not consumed. The total number of consumed drinks is the main primary outcome. All participants will receive a brief course of psychotherapy (including MET). We will explore the effects of DMT (plus brief psychotherapy) on participants' natural alcohol consumption weekly for 4 weeks, using Timeline follow-back (TLFB), to measure the percentage of heavy drinking days, abstinent days, and total amount of alcohol consumption and categorical outcomes of abstinence, no heavy drinking and a 2-level reduction in WHO drinking risk will be compared. Hypotheses: Relative to control (diphenhydramine, IV, 25 mg plus MET), a single psychedelic dose of intravenous (IV) DMT (0.3 mg/kg) plus brief psychotherapy (including MET) in individuals with AUD will 1) be safe and well-tolerated, 2) reduce alcohol consumption measured in the laboratory using Alcohol Drinking Paradigm, the day after, and 3) reduce alcohol drinking over the following 4 weeks.

PROJECT NARRATIVE Given the urgent need to develop novel pharmacological treatment for alcohol use disorder (AUD), and the promising preliminary reports of the fast-acting and long-lasting effects of psychedelic compounds, we propose to investigate the therapeutic potential of psychedelic N,N-dimethyltryptamine (DMT) plus a brief course of psychotherapy (including Motivational Enhancement Therapy (MET)) on alcohol use disorder (AUD) in a proof- of-concept, randomized (1:1), placebo-controlled, double-blind, parallel group, laboratory study and clinical trial.