Vaporized Cannabis Administration and Co-Administration of Alcohol on Impairment

This human laboratory study will use cognitive, behavioral, and subjective measures to characterize impairment associated with co-use of alcohol and vaporized cannabis. Participants (n=32) will complete 7 double-blind, double-dummy outpatient sessions in randomized order. In each session, participants will self-administer placebo (0 mg THC) or active vaporized cannabis (5 or 25 mg THC, via a handheld vaporizer called the Mighty Medic) and a placebo drink (BAC 0.0%) or alcohol drink calculated to produce a breath alcohol concentration (BAC) of 0.05%. Participants will also complete a positive control session in which the participant administers placebo cannabis and alcohol at a target BAC of 0.08% (the legal threshold for driving impairment in most U.S. states).

Inclusion Criteria: 1. Have provided written informed consent 2. Be at least 21 years of age 3. Be in good general health based on a physical examination, medical history, vital signs, and screening urine and blood tests 4. Not be pregnant or nursing (if female). All females must have a negative serum pregnancy test at the screening visit and a negative urine pregnancy test at each study visit 5. Have not donated blood in the prior 30 days 6. Report at least 1 day of binge drinking in the past 3 months (greater than 4 or 5 drinks on a single occasion for women and men, respectively) 7. Report at least 1 use of cannabis in the past 3 years 8. Provide negative urine test for illicit drug use (excluding THC) and negative breath alcohol test (0% BAC) at screening and before study sessions 9. Report at least 1 lifetime instance of simultaneous alcohol and cannabis use 10. Current concomitant prescription medication use that may interact with the investigational study drug, including inhibitors and inducers of CYP2CP and CYP3A4 as well as highly-protein bound drugs and drugs with a narrow therapeutic index such as warfarin, cyclosporine, and amphotericin B Exclusion Criteria: 1. Psychoactive drug use (aside from cannabis, nicotine, alcohol, or caffeine) in the past month 2. History of or current evidence of significant medical condition that would put the participant at risk 3. Evidence of current psychiatric condition (MINI for DSM-V) 4. Meet criteria for severe alcohol use disorder (MINI for DSM-V) 5. CIWA-Ar score \> 9 6. Use of cannabis, on average, more than 3 days/week over past 3 months 7. Enrollment in another clinical trial or receiving of any drug as part of research within past 30 days 8. Shipley vocabulary score \