Vaporized Cannabis Administration and Co-Administration of Alcohol on Impairment

This study will be conducted at the Johns Hopkins Behavioral Pharmacology Research Unit (BPRU). Participants will complete a screening visit, and, if eligible, will then complete 7 experimental drug administration sessions in randomized order where the participant will vaporize cannabis-containing capsules (or "pods") (containing 0, 5, or 25mg THC) with a drink that contains no alcohol or alcohol (alcohol-containing drinks will be calculated to produce a breath alcohol concentration, BAC, of 0.05%). There is also a positive control session where participants will vaporize placebo cannabis with an alcohol drink calculated to produce a BAC of 0.08%. Each session will last approximately 8 hours and will be separated by at least 48 hours to allow for sufficient drug washout. Participants may complete up to 2 sessions per week. Drugs will be administered in a double-blind and double-dummy fashion (i.e., participants will always receive both active or placebo cannabis and active or placebo alcohol). During each session, a battery of assessments including blood collection, subjective questionnaire administration, cognitive performance testing, and simulated driving will be conducted.