In 1970, marijuana was classified as a schedule 1 drug in the United States: the strictest designation possible, meaning it was completely illegal and had no recognized medical uses. For decades, this view persisted and set back research on the drug's mechanisms and effects. Today, marijuana’s therapeutic benefits are widely acknowledged, and some nations have legalized medical use or are moving in that direction. But a growing recognition for marijuana’s medical value doesn’t answer the question: is recreational marijuana use bad for your brain? 

Source: ted.com