A psychoactive drug or psychotropic substance is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness, and behavior. In Cannabis (/ˈkænəbɪs/) is a genus of flowering plants in the family Cannabaceae. The number of species within the gen... More, the psychoactive component is THC, or Tetrahydrocaannabinol, is the chemical responsible for most of the marijuana’s psychoactive effects. It behave... More. CBD is completely non-psychoactive and non-intoxicating.