Effect of Cannabis on Cigarette Use Behavior

A full-factorial laboratory study will be conducted to determine the impact of acute THC administration on the dose-related motivational, subjective, and physiological effects of combustible cigarettes. This study will employ a double-blind, placebo-controlled, within-subjects crossover design to examine the dose-effects of THC on combustible tobacco use. The study will use multiple active doses of THC and placebo (0, 5, and 30 mg; corresponding to 0, 1, and 6 standard THC unit doses). Participants will be randomized to either smoked or vaporized THC administration using a between-subjects approach to evaluate the effect of congruent versus incongruent routes of THC and tobacco administration on study outcomes.