Which substance is identified as the principal psychoactive chemical in marijuana?

• A. LSD
• B. PCP
• C. MDMA
• D. THC

Answer: (D)

The substance that drives marijuana’s psychoactive effects is THC, short for delta-9-tetrahydrocannabinol. THC primarily activates the brain’s endocannabinoid system by binding to CB1 receptors, which are concentrated in areas that regulate memory, mood, perception, and coordination. This receptor activation alters neurotransmitter release and produces the characteristic high—altered sensations, euphoria, slowed thinking, and increased appetite. Marijuana does contain other cannabinoids, like CBD, but THC is the main component responsible for the psychoactive experience because of its potency and receptor activity. The other substances listed are different drugs with distinct mechanisms and effects, not the primary psychoactive constituent of marijuana.