LSD's hallucinogenic effects last an unusually long amount of time; 12 to 18 hours, to be precise. That's no surprise to scientists—or to anyone who's taken the drug. This duration, which is longer than any other hallucinogen, has puzzled scientists ever since they began intensely researching the drug in the '60s and '70s. But in a new study out this week, scientists claim to have found the key mechanism behind this staying power: Once ingested, LSD travels into brain receptors where it gets stuck—literally stuck—within a side pocket. This new understanding, they say, could help them to develop new, longer-lasting drugs to treat a variety of psychological disorders.