People who used marijuana as teens have significantly worse memories than those who didn’t, according to a new study published in the journal Hippocampus. Scientists from Northwestern University Feinberg School of Medicine tested the memories of 97 people and discovered that those who smoked pot nearly every day for a period of three years scored about 18 percent worse on long-term memory tests than those who didn’t. The more marijuana was used, the worse the memory was. (Time)