Cannabis contains chemicals which mimic ones found in our brain. One is THC, which produces the high associated with pot use. Another, called CBD, shows promise for treating seizures, addiction, and insomnia. NOVA joins scientists and experts around the country. What risks does cannabis pose to the developing adolescent brain? Does heavy cannabis use impair intelligence, increase psychosis, or even put future generations at risk for addiction? As cannabis becomes socially accepted, scientists are racing to understand the long-term health consequences.