Which substance in marijuana is primarily responsible for its psychoactive effects?

The psychoactive effects of marijuana are primarily attributed to THC, or tetrahydrocannabinol. THC interacts with cannabinoid receptors in the brain, particularly the CB1 receptors, which are part of the endocannabinoid system. This interaction produces effects such as euphoria, relaxation, altered sensory perception, and an increase in appetite, commonly referred to as "the munchies."

In contrast, substances like GHB, LSD, and PCP have different mechanisms of action and effects. GHB is a depressant that affects the central nervous system and is known for its sedative properties. LSD is a hallucinogen that primarily affects serotonin receptors, leading to altered thoughts and emotions. PCP, originally developed as an anesthetic, produces dissociative and hallucinogenic effects through its action on NMDA receptors. Each of these substances operates through different pathways in the brain compared to THC, which is why THC is specifically identified for its psychoactive properties in marijuana.