Behavioral Pharmacology of Orally Administered THC and D-limonene

The current clinical trial will investigate the interaction of orally administered d-limonene (limonene) and delta-9-tetrahydrocannabinol (THC). Limonene is a flavor/fragrance component common to many plants, including cannabis. The investigators have previously demonstrated that vaporized limonene can impact the acute effects of THC. The purpose of this study is to examine whether orally administered limonene modulates the acute effects of orally co-administered THC in a manner similar to when these substances are inhaled A controlled laboratory study will be completed at Johns Hopkins evaluating placebo, THC alone, and four ascending doses of d-limonene in combination with THC. Participants will be healthy adults with experience using cannabis. A total of 6 outpatient drug administration sessions will be conducted for each evaluable participant. The investigators will recruit study volunteers until 20 participants complete the protocol.